Planet Hunters is a citizen science project to find exoplanets using human eyes. It does this by having users analyze data from the NASA Kepler space telescope and the NASA Transiting Exoplanet Survey Satellite . It was launched by a team led by Debra Fischer at Yale University , as part of the Zooniverse project.
138-512: The project was launched on December 16, 2010, after the first Data Release of Kepler data as the Planet Hunters Project. 300,000 volunteers participated in the project and the project team published 8 scientific papers. On December 14, 2014, the project was re-launched as Planet Hunters 2.0, with an improved website and considering that the volunteers will look at K2 data. As of November 2018 Planet Hunters had identified 50% of
276-451: A degree of the position predicted by Le Verrier. Its largest moon, Triton , was discovered shortly thereafter, though none of the planet's remaining moons were located telescopically until the 20th century. The planet's distance from Earth gives it a small apparent size , and its distance from the Sun renders it very dim, making it challenging to study with Earth-based telescopes. Only
414-424: A random planetary orbit being along the line-of-sight to a star is the diameter of the star divided by the diameter of the orbit. For an Earth-size planet at 1 AU transiting a Sun-like star the probability is 0.47%, or about 1 in 210. For a planet like Venus orbiting a Sun-like star the probability is slightly higher, at 0.65%; If the host star has multiple planets, the probability of additional detections
552-462: A soft focus to provide excellent photometry , rather than sharp images. The mission goal was a combined differential photometric precision (CDPP) of 20 ppm for a m (V)=12 Sun-like star for a 6.5-hour integration, though the observations fell short of this objective (see mission status ). The focal plane of the spacecraft's camera is made out of forty-two 50 × 25 mm (2 × 1 in) CCDs at 2200×1024 pixels each, possessing
690-586: A candidate is a real planet. One of the methods, called doppler spectroscopy , requires follow-up observations from ground-based telescopes. This method works well if the planet is massive or is located around a relatively bright star. While current spectrographs are insufficient for confirming planetary candidates with small masses around relatively dim stars, this method can be used to discover additional massive non-transiting planet candidates around targeted stars. In multiplanetary systems, planets can often be confirmed through transit timing variation by looking at
828-412: A cost of about $ 20 million per year. NASA contacted the spacecraft using the X band communication link twice a week for command and status updates. Scientific data are downloaded once a month using the K a band link at a maximum data transfer rate of approximately 550 kB/s . The high gain antenna is not steerable so data collection is interrupted for a day to reorient the whole spacecraft and
966-431: A depth of 7,000 km, the conditions may be such that methane decomposes into diamond crystals that rain downwards like hailstones. Scientists believe that this kind of diamond rain occurs on Jupiter, Saturn, and Uranus. Very-high-pressure experiments at Lawrence Livermore National Laboratory suggest that the top of the mantle may be an ocean of liquid carbon with floating solid 'diamonds'. The core of Neptune
1104-416: A dielectric interference coating to minimize the formation of color centers and atmospheric moisture absorption. In terms of photometric performance, Kepler worked well, much better than any Earth-bound telescope, but short of design goals. The objective was a combined differential photometric precision (CDPP) of 20 parts per million (PPM) on a magnitude 12 star for a 6.5-hour integration. This estimate
1242-488: A fixed field of view (FOV) against the sky. The diagram to the right shows the celestial coordinates and where the detector fields are located, along with the locations of a few bright stars with celestial north at the top left corner. The mission website has a calculator that will determine if a given object falls in the FOV, and if so, where it will appear in the photo detector output data stream. Data on exoplanet candidates
1380-606: A frequency range of 50–12 kHz at magnetic latitudes 7–33˚. These plasma wave detections were possibly triggered by lightning over 20 minutes in the ammonia clouds of the magnetosphere. During Voyager 2 ’s closest approach to Neptune, the PWS instrument provided Neptune's first plasma wave detections at a sample rate of 28,800 samples per second. The measured plasma densities range from 10 – 10 cm . Neptunian lightning may occur in three cloud layers, with microphysical modelling suggesting that most of these occurrences happen in
1518-578: A further 3,199 unconfirmed planet candidates. Four planets have been confirmed through Kepler's K2 mission. In November 2013, astronomers estimated, based on Kepler space mission data, that there could be as many as 40 billion rocky Earth-size exoplanets orbiting in the habitable zones of Sun-like stars and red dwarfs within the Milky Way . It is estimated that 11 billion of these planets may be orbiting Sun-like stars. The nearest such planet may be 3.7 parsecs (12 ly ) away, according to
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#17327934985601656-519: A higher proportion of ices such as water, ammonia and methane . Similar to Uranus, its interior is primarily composed of ices and rock; both planets are normally considered "ice giants" to distinguish them. Along with Rayleigh scattering , traces of methane in the outermost regions make Neptune appear faintly blue. In contrast to the strongly seasonal atmosphere of Uranus, which can be featureless for long periods of time, Neptune's atmosphere has active and consistently visible weather patterns. At
1794-410: A hot, dense supercritical fluid . This fluid, which has a high electrical conductivity, is sometimes called a water–ammonia ocean. The mantle may consist of a layer of ionic water in which the water molecules break down into a soup of hydrogen and oxygen ions , and deeper down superionic water in which the oxygen crystallizes but the hydrogen ions float around freely within the oxygen lattice. At
1932-461: A large sample of stars to achieve several key goals: Most of the exoplanets previously detected by other projects were giant planets , mostly the size of Jupiter and bigger. Kepler was designed to look for planets 30 to 600 times less massive, closer to the order of Earth's mass (Jupiter is 318 times more massive than Earth). The method used, the transit method , involves observing repeated transit of planets in front of their stars, which causes
2070-485: A letter and urged Berlin Observatory astronomer Galle to search with the observatory's refractor . Heinrich d'Arrest , a student at the observatory, suggested to Galle that they could compare a recently drawn chart of the sky in the region of Le Verrier's predicted location with the current sky to seek the displacement characteristic of a planet , as opposed to a fixed star. On the evening of 23 September 1846,
2208-401: A low temperature of 51.8 K (−221.3 °C). At a depth where the atmospheric pressure equals 1 bar (100 kPa ), the temperature is 72.00 K (−201.15 °C). Deeper inside the layers of gas, the temperature rises steadily. As with Uranus, the source of this heating is unknown, but the discrepancy is larger: Uranus only radiates 1.1 times as much energy as it receives from
2346-452: A mission lasting 7 to 8 years, as opposed to the originally planned 3.5 years, would be needed to find all transiting Earth-sized planets. On April 4, 2012, the Kepler mission was approved for extension through the fiscal year 2016, but this also depended on all remaining reaction wheels staying healthy, which turned out not to be the case (see Reaction wheel issues below). Kepler orbits
2484-670: A much higher probability of detecting Earth-sized planets than the Hubble Space Telescope , which has a field of view of only 10 sq. arc-minutes . Moreover, Kepler is dedicated to detecting planetary transits, while the Hubble Space Telescope is used to address a wide range of scientific questions, and rarely looks continuously at just one starfield. Of the approximately half-million stars in Kepler's field of view, around 150,000 stars were selected for observation. More than 90,000 are G-type stars on, or near,
2622-471: A multiplanet system plot, there are many different patterns of transit. Due to the different sizes of planets, the transits dip down to different points. Stellar flares are observed when there is an explosion on the surface of a star. This will cause the star's brightness to shoot up considerably, with a steep drop off. So far, over 12 million observations have been analyzed. Out of those, 34 candidate planets had been found as of July 2012. In October 2012 it
2760-514: A new planet. In 1845–1846, Urbain Le Verrier , developed his own calculations independently from Adams, but aroused no enthusiasm among his compatriots. In June 1846, upon seeing Le Verrier's first published estimate of the planet's longitude and its similarity to Adams's estimate, Airy persuaded James Challis to search for the planet. Challis vainly scoured the sky throughout August and September. Challis had, in fact, observed Neptune
2898-623: A process called dispositioning. Those which pass the dispositioning are called Kepler planet candidates. The KOI archive is not static, meaning that a Kepler candidate could end up in the false-positive list upon further inspection. In turn, KOIs that were mistakenly classified as false positives could end up back in the candidates list. Not all the planet candidates go through this process. Circumbinary planets do not show strictly periodic transits, and have to be inspected through other methods. In addition, third-party researchers use different data-processing methods, or even search planet candidates from
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#17327934985603036-463: A second one failed, disabling the collection of science data and threatening the continuation of the mission. On August 15, 2013, NASA announced that they had given up trying to fix the two failed reaction wheels. This meant the current mission needed to be modified, but it did not necessarily mean the end of planet hunting. NASA had asked the space science community to propose alternative mission plans "potentially including an exoplanet search, using
3174-424: A second reaction wheel failed on May 11, 2013, ending Kepler's primary mission. The spacecraft was put into safe mode, then from June to August 2013 a series of engineering tests were done to try to recover either failed wheel. By August 15, 2013, it was decided that the wheels were unrecoverable, and an engineering report was ordered to assess the spacecraft's remaining capabilities. This effort ultimately led to
3312-592: A signal that is easier to check, scientists expected the first reported results to be larger Jupiter-size planets in tight orbits. The first of these were reported after only a few months of operation. Smaller planets, and planets farther from their sun would take longer, and discovering planets comparable to Earth were expected to take three years or longer. Data collected by Kepler is also being used for studying variable stars of various types and performing asteroseismology , particularly on stars showing solar-like oscillations . Once Kepler has collected and sent back
3450-455: A slight reduction in the star's apparent magnitude , on the order of 0.01% for an Earth-size planet. The degree of this reduction in brightness can be used to deduce the diameter of the planet, and the interval between transits can be used to deduce the planet's orbital period, from which estimates of its orbital semi-major axis (using Kepler's laws ) and its temperature (using models of stellar radiation) can be calculated. The probability of
3588-463: A threshold crossing event. These signals are individually inspected in two inspection rounds, with the first round taking only a few seconds per target. This inspection eliminates erroneously selected non-signals, signals caused by instrumental noise and obvious eclipsing binaries. Threshold crossing events that pass these tests are called Kepler Objects of Interest (KOI), receive a KOI designation and are archived. KOIs are inspected more thoroughly in
3726-423: A total resolution of 94.6 megapixels , which at the time made it the largest camera system launched into space. The array was cooled by heat pipes connected to an external radiator. The CCDs were read out every 6.5 seconds (to limit saturation) and co-added on board for 58.89 seconds for short cadence targets, and 1765.5 seconds (29.4 minutes) for long cadence targets. Due to the larger bandwidth requirements for
3864-457: A year before the planet's subsequent discoverer, Johann Gottfried Galle , and on two occasions, 4 and 12 August 1845. However, his out-of-date star maps and poor observing techniques meant that he failed to recognize the observations as such until he carried out later analysis. Challis was full of remorse but blamed his neglect on his maps and the fact that he was distracted by his concurrent work on comet observations. Meanwhile, Le Verrier sent
4002-432: Is 10–100 times greater than at the poles. This is interpreted as evidence for upwelling at the equator and subsidence near the poles, as photochemistry cannot account for the distribution without meridional circulation. In 2007, it was discovered that the upper troposphere of Neptune's south pole was about 10 K warmer than the rest of its atmosphere, which averages about 73 K (−200 °C). The temperature differential
4140-422: Is 28.32°, which is similar to the tilts of Earth (23°) and Mars (25°). As a result, Neptune experiences seasonal changes similar to those on Earth. The long orbital period of Neptune means that the seasons last for forty Earth years. Its sidereal rotation period (day) is roughly 16.11 hours. Because its axial tilt is comparable to Earth's, the variation in the length of its day over the course of its long year
4278-495: Is 29.81 AU, and the aphelion distance is 30.33 AU. Neptune's orbital eccentricity is only 0.008678, making it the planet in the Solar System with the second most circular orbit after Venus . The orbit of Neptune is inclined 1.77° compared to that of Earth. On 11 July 2011, Neptune completed its first full barycentric orbit since its discovery in 1846; it did not appear at its exact discovery position in
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4416-518: Is banded by clouds of varying compositions depending on altitude. The upper-level clouds lie at pressures below one bar, where the temperature is suitable for methane to condense. For pressures between one and five bars (100 and 500 kPa), clouds of ammonia and hydrogen sulfide are thought to form. Above a pressure of five bars, the clouds may consist of ammonia, ammonium sulfide , hydrogen sulfide and water. Deeper clouds of water ice should be found at pressures of about 50 bars (5.0 MPa), where
4554-513: Is commonly used. In Māori , the planet is called Tangaroa , named after the Māori god of the sea . In Nahuatl , the planet is called Tlāloccītlalli , named after the rain god Tlāloc . In Thai , Neptune is referred to by the Westernised name Dao Nepchun/Nepjun ( ดาวเนปจูน ) but is also called Dao Ket ( ดาวเกตุ , lit. ' star of Ketu ' ), after Ketu ( केतु ),
4692-469: Is enough to let methane, which elsewhere is frozen in the troposphere, escape into the stratosphere near the pole. The relative "hot spot" is due to Neptune's axial tilt , which has exposed the south pole to the Sun for the last quarter of Neptune's year, or roughly 40 Earth years. As Neptune slowly moves towards the opposite side of the Sun, the south pole will be darkened and the north pole illuminated, causing
4830-426: Is faintly blue in the optical spectrum , only slightly more saturated than the blue of Uranus's atmosphere. Early renderings of the two planets greatly exaggerated Neptune's colour contrast "to better reveal the clouds, bands and winds", making it seem deep blue compared to Uranus's off-white. The two planets had been imaged with different systems, making it hard to directly compare the resulting composite images . This
4968-449: Is favoured due to its ability to better explain the occupancy of the populations of small objects observed in the trans-Neptunian region. The current most widely accepted explanation of the details of this hypothesis is known as the Nice model , which is a dynamical evolution scenario that explores the potential effect of a migrating Neptune and the other giant planets on the structure of
5106-571: Is harder to explain Uranus's lack of internal heat while preserving the apparent similarity between the two planets. The average distance between Neptune and the Sun is 4.5 billion km (about 30.1 astronomical units (AU), the mean distance from the Earth to the Sun), and it completes an orbit on average every 164.79 years, subject to a variability of around ±0.1 years. The perihelion distance
5244-399: Is higher than the probability of initial detection assuming planets in a given system tend to orbit in similar planes—an assumption consistent with current models of planetary system formation. For instance, if a Kepler -like mission conducted by aliens observed Earth transiting the Sun, there is a 7% chance that it would also see Venus transiting. Kepler's 115 deg field of view gives it
5382-409: Is likely composed of iron, nickel and silicates , with an interior model giving a mass about 1.2x that of Earth. The pressure at the centre is 7 Mbar (700 GPa), about twice as high as that at the centre of Earth, and the temperature may be 5,400 K (5,100 °C; 9,300 °F). At high altitudes, Neptune's atmosphere is 80% hydrogen and 19% helium . A trace amount of methane
5520-558: Is nearly four times that of Earth . Neptune, like Uranus , is an ice giant , a subclass of giant planet , because they are smaller and have higher concentrations of volatiles than Jupiter and Saturn. In the search for exoplanets , Neptune has been used as a metonym : discovered bodies of similar mass are often referred to as "Neptunes", just as scientists refer to various extrasolar bodies as "Jupiters". Neptune's internal structure resembles that of Uranus . Its atmosphere forms about 5 to 10% of its mass and extends perhaps 10 to 20% of
5658-426: Is not any more extreme. Because Neptune is not a solid body, its atmosphere undergoes differential rotation . The wide equatorial zone rotates with a period of about 18 hours, which is slower than the 16.1-hour rotation of the planet's magnetic field. By contrast, the reverse is true for the polar regions where the rotation period is 12 hours. This differential rotation is the most pronounced of any planet in
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5796-544: Is possible that not all PHT planet candidates become real (confirmed) exoplanets. Some of them may be grazing eclipsing binaries . On October 19, 2021, the project Planet Hunters: NGTS was launched. It uses a dataset from the Next Generation Transit Survey to find transiting planets. It is the first Planet Hunters project that uses data from a ground-based telescope. The project looks at candidates that were already automatically filtered, similar to
5934-407: Is present. Prominent absorption bands of methane exist at wavelengths above 600 nm, in the red and infrared portion of the spectrum. As with Uranus, this absorption of red light by atmospheric methane is part of what gives Neptune its faint blue hue, which is more pronounced for Neptune's due to concentrated haze in Uranus's atmosphere. Neptune's atmosphere is subdivided into two main regions:
6072-432: Is responsible. In June 2016 the project found 32 likely eclipsing binaries . The work also announced likely exoplanets. In February 2018 the first transiting exocomets were discovered. The dips were found by one of the authors, a Planet Hunters participant, in a visual search over five months of the complete Q1-Q17 Kepler light curve archive spanning 201250 target stars. In February 2022 Planet Hunters:TESS announced
6210-575: Is submitted to the Kepler Follow-up Program , or KFOP, to conduct follow-up observations. Kepler's field of view covers 115 square degrees , around 0.25 percent of the sky, or "about two scoops of the Big Dipper". Thus, it would require around 400 Kepler-like telescopes to cover the whole sky. The Kepler field contains portions of the constellations Cygnus , Lyra , and Draco . The nearest star system in Kepler's field of view
6348-471: Is that the ice giants were not formed by core accretion but from instabilities within the original protoplanetary disc and later had their atmospheres blasted away by radiation from a nearby massive OB star . An alternative concept is that they formed closer to the Sun, where the matter density was higher, and then subsequently migrated to their current orbits after the removal of the gaseous protoplanetary disc. This hypothesis of migration after formation
6486-490: Is the eighth and farthest known planet from the Sun . It is the fourth-largest planet in the Solar System by diameter, the third-most-massive planet, and the densest giant planet . It is 17 times the mass of Earth . Compared to its fellow ice giant Uranus , Neptune is slightly more massive, but denser and smaller. Being composed primarily of gases and liquids, it has no well-defined solid surface, and orbits
6624-401: Is the trinary star system Gliese 1245 , 15 light years from the Sun. The brown dwarf WISE J2000+3629, 22.8 ± 1 light years from the Sun is also in the field of view, but is invisible to Kepler due to emitting light primarily in infrared wavelengths. The scientific objective of the Kepler space telescope was to explore the structure and diversity of planetary systems . This spacecraft observes
6762-690: Is thought to be a " skin effect " and not due to any deeper atmospheric processes. At 70°S latitude, a high-speed jet travels at a speed of 300 m/s. Due to seasonal changes, the cloud bands in the southern hemisphere of Neptune have been observed to increase in size and albedo . This trend was first seen in 1980. The long orbital period of Neptune results in seasons lasting 40 Earth years. Neptune differs from Uranus in its typical level of meteorological activity. Voyager 2 observed weather phenomena on Neptune during its 1989 flyby, but no comparable phenomena on Uranus during its 1986 flyby. The abundance of methane, ethane and acetylene at Neptune's equator
6900-774: The Kepler Science Office (SO). Accordingly, the SOC develops the pipeline data processing software based on scientific algorithms developed jointly by the SO and SOC. During operations, the SOC: The SOC also evaluates the photometric performance on an ongoing basis and provides the performance metrics to the SO and Mission Management Office. Finally, the SOC develops and maintains the project's scientific databases, including catalogs and processed data. The SOC finally returns calibrated data products and scientific results back to
7038-588: The dipole moment in strength. By contrast, Earth, Jupiter and Saturn have only relatively small quadrupole moments, and their fields are less tilted from the polar axis. The large quadrupole moment of Neptune may be the result of an offset from the planet's centre and geometrical constraints of the field's dynamo generator. Measurements by Voyager 2 in extreme-ultraviolet and radio frequencies revealed that Neptune has faint and weak but complex and unique aurorae ; however, these observations were limited in time and did not contain infrared. Subsequent astronomers using
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#17327934985607176-432: The high-gain antenna was changed from a design using a gimbal to one fixed to the frame of the spacecraft to reduce cost and complexity, at the cost of one observation day per month. The Ames Research Center was responsible for the ground system development, mission operations since December 2009, and scientific data analysis. The initial planned lifetime was three and a half years, but greater-than-expected noise in
7314-430: The main sequence . Thus, Kepler was designed to be sensitive to wavelengths of 400–865 nm where brightness of those stars peaks. Most of the stars observed by Kepler have apparent visual magnitude between 14 and 16 but the brightest observed stars have apparent visual magnitude of 8 or lower. Most of the planet candidates were initially not expected to be confirmed due to being too faint for follow-up observations. All
7452-609: The orbit of Uranus . Subsequent observations revealed substantial deviations from the tables, leading Bouvard to hypothesize that an unknown body was perturbing the orbit through gravitational interaction. In 1843, John Couch Adams began work on the orbit of Uranus using the data he had. He requested extra data from Sir George Airy , the Astronomer Royal , who supplied it in February 1844. Adams continued to work in 1845–1846 and produced several different estimates of
7590-568: The tropopause layer. The persistence of companion clouds shows that some former dark spots may continue to exist as cyclones even though they are no longer visible as a dark feature. Dark spots may dissipate when they migrate too close to the equator or possibly through some other, unknown mechanism. In 1989, Voyager 2 's Planetary Radio Astronomy (PRA) experiment observed around 60 lightning flashes, or Neptunian electrostatic discharges emitting energies over 7 × 10 J . A plasma wave system (PWS) detected 16 electromagnetic wave events with
7728-467: The "K2" follow-on mission observing different fields near the ecliptic. In January 2006, the project's launch was delayed eight months because of budget cuts and consolidation at NASA. It was delayed again by four months in March 2006 due to fiscal problems. At this time, the high-gain antenna was changed from a gimballed design to one fixed to the frame of the spacecraft to reduce cost and complexity, at
7866-621: The DMC for long-term archiving, and distribution to astronomers around the world through the Multimission Archive at STScI (MAST). On July 14, 2012, one of the four reaction wheels used for fine pointing of the spacecraft failed. While Kepler requires only three reaction wheels to accurately aim the telescope, another failure would leave the spacecraft unable to aim at its original field. After showing some problems in January 2013,
8004-590: The Exoplanet Explorers project. The project found four candidate planets so far. In the pre-print five candidates are presented. This includes a giant planet candidate around TIC-165227846 , a mid-M dwarf. This candidate was independently detected by Byrant et al. 2023 and if confirmed could represent the lowest-mass star to host a close-in giant. The Planet Hunters project exploits the fact that humans are better at recognising visual patterns than computers. The website displays an image of data collected by
8142-464: The French Bureau des Longitudes . In October, he sought to name the planet Le Verrier , after himself, and he had loyal support in this from the observatory director, François Arago . This suggestion met with stiff resistance outside France. French almanacs quickly reintroduced the name Herschel for Uranus, after that planet's discoverer Sir William Herschel , and Leverrier for
8280-637: The French and the British over who deserved credit for the discovery. Eventually, an international consensus emerged that Le Verrier and Adams deserved joint credit. Since 1966, Dennis Rawlins has questioned the credibility of Adams's claim to co-discovery, and the issue was re-evaluated by historians with the return in 1998 of the "Neptune papers" (historical documents) to the Royal Observatory, Greenwich . Shortly after its discovery, Neptune
8418-421: The Hubble Space Telescope have not glimpsed the aurorae, in contrast to the more well-defined aurorae of Uranus. Neptune's bow shock , where the magnetosphere begins to slow the solar wind , occurs at a distance of 34.9 times the radius of the planet. The magnetopause , where the pressure of the magnetosphere counterbalances the solar wind, lies at a distance of 23–26.5 times the radius of Neptune. The tail of
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#17327934985608556-504: The Kuiper belt. Neptune's orbit has a profound impact on the region directly beyond it, known as the Kuiper belt . The Kuiper belt is a ring of small icy worlds, similar to the asteroid belt but far larger, extending from Neptune's orbit at 30 AU out to about 55 AU from the Sun. Much in the same way that Jupiter's gravity dominates the asteroid belt , Neptune's gravity dominates
8694-410: The Kuiper belt. Over the age of the Solar System, certain regions of the Kuiper belt became destabilised by Neptune's gravity, creating gaps in its structure. The region between 40 and 42 AU is an example. There do exist orbits within these empty regions where objects can survive for the age of the Solar System. These resonances occur when Neptune's orbital period is a precise fraction of that of
8832-674: The NASA Kepler Space Mission and asks human users (referred to as "Citizen Scientists") to look at the data and see how the brightness of a star changes over time. This brightness data is represented as a graph and referred to as a star's light curve . Such curves are helpful in discovering extrasolar planets due to the brightness of a star decreasing when a planet passes in front of it, as seen from Earth. Periods of reduced brightness can thus provide evidence of planetary transits , but may also be caused by errors in recording, projection, or other phenomena. From time to time,
8970-446: The Solar System, and it results in strong latitudinal wind shear. The formation of the ice giants, Neptune and Uranus, has been difficult to model precisely. Current models suggest that the matter density in the outer regions of the Solar System was too low to account for the formation of such large bodies from the traditionally accepted method of core accretion , and various hypotheses have been advanced to explain their formation. One
9108-490: The Sun , which avoids Earth occultations , stray light, and gravitational perturbations and torques inherent in an Earth orbit. NASA has characterized Kepler's orbit as "Earth-trailing". With an orbital period of 372.5 days, Kepler is slowly falling farther behind Earth (about 16 million miles per annum ). As of May 1, 2018 , the distance to Kepler from Earth was about 0.917 AU (137 million km). This means that after about 26 years Kepler will reach
9246-597: The Sun once every 164.8 years at an orbital distance of 30.1 astronomical units (4.5 billion kilometres; 2.8 billion miles). It is named after the Roman god of the sea and has the astronomical symbol [REDACTED] , representing Neptune's trident . Neptune is not visible to the unaided eye and is the only planet in the Solar System that was found from mathematical predictions derived from indirect observations rather than being initially observed by direct empirical observation , when unexpected changes in
9384-413: The Sun, Neptune's outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching 55 K (−218 °C ; −361 °F ). Temperatures at the planet's centre are approximately 5,400 K (5,100 °C; 9,300 °F). Neptune has a faint and fragmented ring system (labelled "arcs"), discovered in 1984 and confirmed by Voyager 2 . Some of
9522-549: The Sun, making Neptune the ninth planet from the Sun during this period. The increasingly accurate estimations of Pluto's mass from ten times that of Earth's to far less than that of the Moon and the discovery of the Kuiper belt in 1992 led many astronomers to debate whether Pluto should be considered a planet or as part of the Kuiper belt. In 2006, the International Astronomical Union defined
9660-464: The Sun; whereas Neptune radiates about 2.61 times as much energy as it receives from the Sun. Neptune is over 50% farther from the Sun than Uranus and receives only ~40% of Uranus's amount of sunlight; however, its internal energy is still enough for the fastest planetary winds in the Solar System. Depending on the thermal properties of its interior, the heat left over from Neptune's formation may be sufficient to explain its current heat flow, though it
9798-487: The V magnitude. Planet Hunters TESS (PHT) publishes Community TESS Object of Interest (CTOI) at ExoFOP, which can be promoted into a TESS Object of Interest (TOI). Of the 151 CTOIs submitted by Planet Hunters researchers, 81 were promoted to TOIs (as of September 2022). The following exoplanets first submitted as PHT CTOIs were later researched by other teams (some examples): TOI-1759 b , TOI-1899 b , TOI-2180 b , TOI-4562 b and HD 148193 b (TOI-1836). In September 2013
9936-491: The advent of the Hubble Space Telescope and of large ground-based telescopes with adaptive optics allowed for detailed observations. Neptune was visited by Voyager 2 , which flew by the planet on 25 August 1989; Voyager 2 remains the only spacecraft to have visited it. Like the gas giants ( Jupiter and Saturn ), Neptune's atmosphere is composed primarily of hydrogen and helium , along with traces of hydrocarbons and possibly nitrogen , but contains
10074-628: The billions of stars in the Milky Way have such planets, Kepler's sole scientific instrument is a photometer that continually monitored the brightness of approximately 150,000 main sequence stars in a fixed field of view. These data were transmitted to Earth, then analyzed to detect periodic dimming caused by exoplanets that cross in front of their host star. Only planets whose orbits are seen edge-on from Earth could be detected. Kepler observed 530,506 stars, and had detected 2,778 confirmed planets as of June 16, 2023. The Kepler space telescope
10212-574: The campus of Johns Hopkins University in Baltimore, Maryland . The science data telemetry is decoded and processed into uncalibrated FITS -format science data products by the DMC, which are then passed along to the Science Operations Center (SOC) at NASA Ames Research Center, for calibration and final processing. The SOC at NASA Ames Research Center (ARC) develops and operates the tools needed to process scientific data for use by
10350-431: The cloud deck. These altitudes are in the layer where weather occurs, the troposphere. Weather does not occur in the higher stratosphere or thermosphere. In August 2023, the high-altitude clouds of Neptune vanished, prompting a study spanning thirty years of observations by the Hubble Space Telescope and ground-based telescopes. The study found that Neptune's high-altitude cloud activity is bound to Solar cycles , and not to
10488-421: The cost of one observation day per month. The Kepler observatory was launched on March 7, 2009, at 03:49:57 UTC aboard a Delta II rocket from Cape Canaveral Air Force Station , Florida. The launch was a success and all three stages were completed by 04:55 UTC. The cover of the telescope was jettisoned on April 7, 2009, and the first light images were taken on the next day. On April 20, 2009, it
10626-408: The data , from both the stars and the spacecraft, meant additional time was needed to fulfill all mission goals. Initially, in 2012, the mission was expected to be extended until 2016, but on July 14, 2012, one of the four reaction wheels used for pointing the spacecraft stopped turning, and completing the mission would only be possible if the other three all remained reliable. Then, on May 11, 2013,
10764-402: The data, raw light curves are constructed. Brightness values are then adjusted to take the brightness variations due to the rotation of the spacecraft into account. The next step is processing (folding) light curves into a more easily observable form and letting software select signals that seem potentially transit-like. At this point, any signal that shows potential transit-like features is called
10902-411: The day Galle received the letter, he discovered Neptune just northeast of Iota Aquarii , 1° from the " five degrees east of Delta Capricorn " position Le Verrier had predicted it to be, about 12° from Adams's prediction, and on the border of Aquarius and Capricornus according to the modern IAU constellation boundaries. In the wake of the discovery, there was a nationalistic rivalry between
11040-673: The descending lunar node , who plays a role in Hindu astrology . In Malay , the name Waruna , after the Hindu god of seas , is attested as far back as the 1970s, but was eventually superseded by the Latinate equivalents Neptun (in Malaysian ) or Neptunus (in Indonesian ). The usual adjectival form is Neptunian . The nonce form Poseidean ( / p ə ˈ s aɪ d i ən / ), from Poseidon , has also been used, though
11178-535: The discovery of BD+61 2536 (TIC 470710327), a massive hierarchical triple star system. The system is predicted to undergo multiple phases of mass transfer in the future, and likely end up as a double neutron star gravitational wave progenitor or an exotic Thorne-Zytkow object . Zooniverse projects: Kepler space telescope The Kepler space telescope is a defunct space telescope launched by NASA in 2009 to discover Earth-sized planets orbiting other stars . Named after astronomer Johannes Kepler ,
11316-512: The earliest known telescopic observations ever, Galileo's drawings on 28 Dec. 1612 and 27 Jan. 1613 ( New Style ) contain plotted points that match what is now known to have been the positions of Neptune on those dates. Both times, Galileo seems to have mistaken Neptune for a fixed star when it appeared close—in conjunction —to Jupiter in the night sky . Hence, he is not credited with Neptune's discovery. At his first observation in Dec. 1612, Neptune
11454-402: The easterly direction to 325 m/s westward. At the cloud tops, the prevailing winds range in speed from 400 m/s along the equator to 250 m/s at the poles. Most of the winds on Neptune move in a direction opposite the planet's rotation. The general pattern of winds showed prograde rotation at high latitudes vs. retrograde rotation at lower latitudes. The difference in flow direction
11592-445: The first ground-based observation of a dark spot on Neptune was announced. Neptune's dark spots are thought to occur in the troposphere at lower altitudes than the brighter cloud features, so they appear as holes in the upper cloud decks. As they are stable features that can persist for several months, they are thought to be vortex structures. Often associated with dark spots are brighter, persistent methane clouds that form around
11730-415: The former, these were limited in number to 512 compared to 170,000 for long cadence. However, even though at launch Kepler had the highest data rate of any NASA mission, the 29-minute sums of all 95 million pixels constituted more data than could be stored and sent back to Earth. Therefore, the science team pre-selected the relevant pixels associated with each star of interest, amounting to about 6 percent of
11868-672: The galaxy. Thus, the stars which Kepler observed are roughly the same distance from the Galactic Center as the Solar System , and also close to the galactic plane . This fact is important if position in the galaxy is related to habitability, as suggested by the Rare Earth hypothesis . Orientation is three-axis stabilized by sensing rotations using fine-guidance sensors located on the instrument focal plane (instead of rate sensing gyroscopes, e.g. as used on Hubble ). and using reaction wheels and hydrazine thrusters to control
12006-598: The high gain antenna for communications to Earth. The Kepler space telescope conducted its own partial analysis on board and only transmitted scientific data deemed necessary to the mission in order to conserve bandwidth. Science data telemetry collected during mission operations at LASP is sent for processing to the Kepler Data Management Center (DMC) which is located at the Space Telescope Science Institute on
12144-461: The known planets with an orbital period larger than two years. In 2017 the project Exoplanet Explorers was launched. It was another planet hunting project at Zooniverse and discovered the system K2-138 and the exoplanet K2-288Bb . This project was launched during the television program Stargazing Live and the discovery of the K2-138 system was announced during the program. On December 6, 2018,
12282-453: The lower troposphere , where temperature decreases with altitude, and the stratosphere , where temperature increases with altitude. The boundary between the two, the tropopause , lies at a pressure of 0.1 bars (10 kPa). The stratosphere then gives way to the thermosphere at a pressure lower than 10 to 10 bars (1 to 10 Pa). The thermosphere gradually transitions to the exosphere . Models suggest that Neptune's troposphere
12420-405: The magnetic equator of Neptune is about 14 microteslas (0.14 G ). The dipole magnetic moment of Neptune is about 2.2 × 10 T·m (14 μT· R N , where R N is the radius of Neptune). Neptune's magnetic field has a complex geometry that includes relatively large contributions from non-dipolar components, including a strong quadrupole moment that may exceed
12558-401: The magnetic fields of the two planets, scientists now think the extreme orientation may be characteristic of flows in the planets' interiors. This field may be generated by convective fluid motions in a thin spherical shell of electrically conducting liquids (probably a combination of ammonia, methane and water), resulting in a dynamo action. The dipole component of the magnetic field at
12696-403: The magnetosphere extends out to at least 72 times the radius of Neptune, and likely much farther. Neptune's weather is characterized by extremely dynamic storm systems, with winds reaching speeds of almost 600 m/s (2,200 km/h; 1,300 mph)—exceeding supersonic flow. More typically, by tracking the motion of persistent clouds, wind speeds have been shown to vary from 20 m/s in
12834-600: The methane release to shift to the north pole. In 1989, the Great Dark Spot , an anticyclonic storm system spanning 13,000 km × 6,600 km (8,100 mi × 4,100 mi), was discovered by NASA 's Voyager 2 spacecraft. The storm resembled the Great Red Spot of Jupiter. Some five years later, on 2 November 1994, the Hubble Space Telescope did not see the Great Dark Spot on
12972-430: The mirror is specifically designed to have a mass only 14% that of a solid mirror of the same size. To produce a space telescope system with sufficient sensitivity to detect relatively small planets, as they pass in front of stars, a very high reflectance coating on the primary mirror was required. Using ion assisted evaporation , Surface Optics Corp. applied a protective nine-layer silver coating to enhance reflection and
13110-400: The new planet has been designated PH1b , short for Planet Hunters 1 b. Yellow indicates a circumbinary planet. Light green indicates planet orbiting around one star in a multiple star system. Light blue indicates host stars with a planetary system consisting of two or more planets. Values for the host stars are acquired via SIMBAD and otherwise are cited. The apparent magnitude represents
13248-561: The new planet. Struve came out in favour of the name Neptune on 29 December 1846, to the Saint Petersburg Academy of Sciences , after the colour of the planet as viewed through a telescope. Soon, Neptune became the internationally accepted name. In Roman mythology , Neptune was the god of the sea, identified with the Greek Poseidon . The demand for a mythological name seemed to be in keeping with
13386-452: The nomenclature of the other planets, all of which were named for deities in Greek and Roman mythology. Most languages today use some variant of the name "Neptune" for the planet. In Chinese, Vietnamese, Japanese, and Korean, the planet's name was translated as "sea king star" ( 海王星 ). In Mongolian , Neptune is called Dalain van ( Далайн ван ), reflecting its namesake god's role as
13524-404: The object, such as 1:2, or 3:4. If, say, an object orbits the Sun once for every two Neptune orbits, it will only complete half an orbit by the time Neptune returns to its original position. The most heavily populated resonance in the Kuiper belt, with over 200 known objects, is the 2:3 resonance. Objects in this resonance complete 2 orbits for every 3 of Neptune, and are known as plutinos because
13662-404: The orbit of Uranus led Alexis Bouvard to hypothesise that its orbit was subject to gravitational perturbation by an unknown planet. After Bouvard's death, the position of Neptune was predicted from his observations, independently, by John Couch Adams and Urbain Le Verrier . Neptune was subsequently directly observed with a telescope on 23 September 1846 by Johann Gottfried Galle within
13800-506: The orientation. Kepler was operated out of Boulder, Colorado , by the Laboratory for Atmospheric and Space Physics (LASP) under contract to Ball Aerospace & Technologies . The spacecraft's solar array was rotated to face the Sun at the solstices and equinoxes , so as to optimize the amount of sunlight falling on the solar array and to keep the heat radiator pointing towards deep space. Together, LASP and Ball Aerospace controlled
13938-401: The other side of the Sun and will get back to the neighborhood of the Earth after 51 years. Until 2013 the photometer pointed to a field in the northern constellations of Cygnus , Lyra and Draco , which is well out of the ecliptic plane, so that sunlight never enters the photometer as the spacecraft orbits. This is also the direction of the Solar System's motion around the center of
14076-471: The pixels (5.4 megapixels). The data from these pixels was then requantized, compressed and stored, along with other auxiliary data, in the on-board 16 gigabyte solid-state recorder. Data that was stored and downlinked includes science stars, p-mode stars , smear, black level, background and full field-of-view images. The Kepler primary mirror is 1.4 meters (4.6 ft) in diameter. Manufactured by glass maker Corning using ultra-low expansion (ULE) glass ,
14214-429: The planet's seasons. Neptune's spectra suggest that its lower stratosphere is hazy due to condensation of products of ultraviolet photolysis of methane, such as ethane and ethyne . The stratosphere is home to trace amounts of carbon monoxide and hydrogen cyanide . The stratosphere of Neptune is warmer than that of Uranus due to the elevated concentration of hydrocarbons. For reasons that remain obscure,
14352-576: The planet's thermosphere is at an anomalously high temperature of about 750 K (477 °C; 890 °F). The planet is too far from the Sun for this heat to be generated by ultraviolet radiation. One candidate for a heating mechanism is atmospheric interaction with ions in the planet's magnetic field . Other candidates are gravity waves from the interior that dissipate in the atmosphere. The thermosphere contains traces of carbon dioxide and water, which may have been deposited from external sources such as meteorites and dust. Neptune's atmosphere
14490-532: The planet. Instead, a new storm similar to the Great Dark Spot was found in Neptune's northern hemisphere. The Scooter is another storm, a white cloud group farther south than the Great Dark Spot. This nickname first arose during the months leading up to the Voyager 2 encounter in 1989, when they were observed moving at speeds faster than the Great Dark Spot (and images acquired later would subsequently reveal
14628-476: The presence of clouds moving even faster than those that had initially been detected by Voyager 2 ). The Small Dark Spot is a southern cyclonic storm, the second-most-intense storm observed during the 1989 encounter. It was initially completely dark, but as Voyager 2 approached the planet, a bright core developed, which can be seen in most of the highest-resolution images. In 2018, a newer main dark spot and smaller dark spot were identified and studied. In 2023,
14766-972: The project Planet Hunters TESS (PHT) was launched and is led by astronomer Nora Eisner. This project uses data from the Transiting Exoplanet Survey Satellite (TESS) and is currently active (as of March 2023). This project discovered the Saturn-sized exoplanet TOI-813 b and many more. Until March 2023 PHT discovered 284 exoplanet candidates (e.g. TIC 35021200.01), 15 confirmed exoplanets (e.g. TOI-5174 b) and countless eclipsing binaries . All discovered exoplanet candidates are uploaded to ExoFOP by Nora Eisner or sometimes by another project member (see TOI and CTOI list provided by ExoFOP). All exoplanet candidates are manually checked by multiple project members (volunteers and moderators) and need to pass different tests before they are accepted by Nora Eisner and uploaded to ExoFOP. But it
14904-528: The project discovered the unusual cataclysmic variable KIC 9406652 . In April 2014 the unusually active SU Ursae Majoris-type dwarf nova GALEX J194419.33+491257.0 was discovered. This cataclysmic variable was discovered as a background dwarf nova of KIC 11412044. In January 2016 unusual dips in KIC 8462852 were announced. The unusual light curve of KIC 8462852 (also known as Boyajian's Star) has engendered speculation that an alien civilization's Dyson sphere
15042-450: The project will observe eclipsing binary stars. Essentially these are stars that orbit each other. Much as a planet can interrupt the brightness of a star, another star can too. There is a noticeable difference on the light curves. It will appear as a large transit (a large dip) and a smaller transit (a smaller dip). As of December 2017, there are a total of 621 multiplanet systems , or stars that contains at least two confirmed planets. In
15180-560: The remaining two good reaction wheels and thrusters". On November 18, 2013, the K2 "Second Light" proposal was reported. This would include utilizing the disabled Kepler in a way that could detect habitable planets around smaller, dimmer red dwarfs . On May 16, 2014, NASA announced the approval of the K2 extension. By January 2015, Kepler and its follow-up observations had found 1,013 confirmed exoplanets in about 440 star systems , along with
15318-420: The rest due to instrumental noise sources slightly larger than predicted. Because decrease in brightness from an Earth-size planet transiting a Sun-like star is so small, only 80 ppm, the increased noise means each individual transit is only a 2.7 σ event, instead of the intended 4 σ. This, in turn, means more transits must be observed to be sure of a detection. Scientific estimates indicated that
15456-638: The ruler of the sea. In modern Greek , the planet is called Poseidon ( Ποσειδώνας , Poseidonas ), the Greek counterpart of Neptune. In Hebrew , Rahab ( רהב ), from a Biblical sea monster mentioned in the Book of Psalms , was selected in a vote managed by the Academy of the Hebrew Language in 2009 as the official name for the planet, even though the existing Latin term Neptun ( נפטון )
15594-436: The same day, bringing an end to its nine-year service. Kepler observed 530,506 stars and discovered 2,662 exoplanets over its lifetime. A newer NASA mission, TESS , launched in 2018, is continuing the search for exoplanets. The telescope has a mass of 1,039 kilograms (2,291 lb) and contains a Schmidt camera with a 0.95-meter (37.4 in) front corrector plate (lens) feeding a 1.4-meter (55 in) primary mirror —at
15732-462: The scientists. On January 6, 2015, NASA announced the 1,000th confirmed exoplanet discovered by the Kepler space telescope. Four of the newly confirmed exoplanets were found to orbit within habitable zones of their related stars : three of the four, Kepler-438b , Kepler-442b and Kepler-452b , are almost Earth-size and likely rocky; the fourth, Kepler-440b , is a super-Earth . On May 10, 2016, NASA verified 1,284 new exoplanets found by Kepler,
15870-439: The selected stars are observed simultaneously, with the spacecraft measuring variations in their brightness every thirty minutes. This provides a better chance for seeing a transit. The mission was designed to maximize the probability of detecting planets orbiting other stars. Because Kepler must observe at least three transits to confirm that the dimming of a star was caused by a transiting planet, and because larger planets give
16008-407: The single largest finding of planets to date. Kepler data have also helped scientists observe and understand supernovae ; measurements were collected every half-hour so the light curves were especially useful for studying these types of astronomical events. On October 30, 2018, after the spacecraft ran out of fuel, NASA announced that the telescope would be retired. The telescope was shut down
16146-448: The sky because Earth was in a different location in its 365.26-day orbit. Because of the motion of the Sun in relation to the barycentre of the Solar System, on 11 July, Neptune was not at its exact discovery position in relation to the Sun—if the more common heliocentric coordinate system is used, the discovery longitude was reached on 12 July 2011. The axial tilt of Neptune
16284-471: The spacecraft from a mission operations center located on the research campus of the University of Colorado . LASP performs essential mission planning and the initial collection and distribution of the science data. The mission's initial life-cycle cost was estimated at US$ 600 million, including funding for 3.5 years of operation. In 2012, NASA announced that the Kepler mission would be funded until 2016 at
16422-427: The spacecraft successfully sent its first science data to Earth. It was discovered that Kepler had entered safe mode on June 15. A second safe mode event occurred on July 2. In both cases the event was triggered by a processor reset . The spacecraft resumed normal operation on July 3 and the science data that had been collected since June 19 was downlinked that day. On October 14, 2009, the cause of these safing events
16560-450: The spacecraft was launched into an Earth-trailing heliocentric orbit . The principal investigator was William J. Borucki . After nine and a half years of operation, the telescope's reaction control system fuel was depleted, and NASA announced its retirement on October 30, 2018. Designed to survey a portion of Earth's region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and to estimate how many of
16698-406: The temperature reaches 273 K (0 °C; 32 °F). Underneath, clouds of ammonia and hydrogen sulfide may be found. High-altitude clouds on Neptune have been observed casting shadows on the opaque cloud deck below. There are high-altitude cloud bands that wrap around the planet at constant latitudes. These circumferential bands have widths of 50–150 km and lie about 50–110 km above
16836-412: The time between successive transits, which may vary if planets are gravitationally perturbed by each other. This helps to confirm relatively low-mass planets even when the star is relatively distant. Transit timing variations indicate that two or more planets belong to the same planetary system. There are even cases where a non-transiting planet is also discovered in this way. Neptune Neptune
16974-483: The time of its launch this was the largest mirror on any telescope outside Earth orbit, though the Herschel Space Observatory took this title a few months later. Its telescope has a 115 deg (about 12-degree diameter) field of view (FoV), roughly equivalent to the size of one's fist held at arm's length. Of this, 105 deg is of science quality, with less than 11% vignetting . The photometer has
17112-492: The time of the Voyager ;2 flyby in 1989, the planet's southern hemisphere had a Great Dark Spot comparable to the Great Red Spot on Jupiter. In 2018, a newer main dark spot and smaller dark spot were identified and studied. These weather patterns are driven by the strongest sustained winds of any planet in the Solar System, as high as 2,100 km/h (580 m/s; 1,300 mph). Because of its great distance from
17250-437: The transit signal. Another method to rule out planet candidates is astrometry for which Kepler can collect good data even though doing so was not a design goal. While Kepler cannot detect planetary-mass objects with this method, it can be used to determine if the transit was caused by a stellar-mass object. There are a few different exoplanet detection methods which help to rule out false positives by giving further proof that
17388-415: The unprocessed light curve data. As a consequence, those planets may be missing KOI designation. Once suitable candidates have been found from Kepler data, it is necessary to rule out false positives with follow-up tests. Usually, Kepler candidates are imaged individually with more-advanced ground-based telescopes in order to resolve any background objects which could contaminate the brightness signature of
17526-442: The usual adjectival form of Poseidon is Poseidonian ( / ˌ p ɒ s aɪ ˈ d oʊ n i ən / ). From its discovery in 1846 until the discovery of Pluto in 1930, Neptune was the farthest known planet. When Pluto was discovered, it was considered a planet, and Neptune thus became the second-farthest known planet, except for a 20-year period between 1979 and 1999 when Pluto's elliptical orbit brought it closer than Neptune to
17664-476: The water clouds of the troposphere or the shallow ammonia clouds of the magnetosphere. Neptune is predicted to have 1/19 the lightning flash rate of Jupiter and to display most of its lightning activity at high latitudes. However, lightning on Neptune seems to resemble lightning on Earth rather than Jovian lightning. Neptune's more varied weather when compared to Uranus is due in part to its higher internal heating . The upper regions of Neptune's troposphere reach
17802-399: The way towards the core. Pressure in the atmosphere reaches about 10 GPa , or about 10 atmospheres. Increasing concentrations of methane , ammonia and water are found in the lower regions of the atmosphere. The mantle is equivalent to 10 to 15 Earth masses and is rich in water, ammonia and methane. As is customary in planetary science, this mixture is called icy even though it is
17940-492: The word "planet" for the first time, reclassifying Pluto as a " dwarf planet " and making Neptune once again the outermost-known planet in the Solar System. Neptune's mass of 1.0243 × 10 kg is intermediate between Earth and the larger gas giants : it is 17 times that of Earth but just 1/19th that of Jupiter . Its gravity at 1 bar is 11.15 m/s , 1.14 times the surface gravity of Earth, and surpassed only by Jupiter. Neptune's equatorial radius of 24,764 km
18078-517: Was almost stationary in the sky because it had just turned retrograde that day. This apparent backward motion is created when Earth's orbit takes it past an outer planet. Because Neptune was only beginning its yearly retrograde cycle, the motion of the planet was far too slight to be detected with Galileo's small telescope. In 2009, a study suggested that Galileo was at least aware that the "star" he had observed had moved relative to fixed stars. In 1821, Alexis Bouvard published astronomical tables of
18216-546: Was announced that the Kepler science team had concluded that further refinement of the focus would dramatically increase the scientific return. On April 23, 2009, it was announced that the focus had been successfully optimized by moving the primary mirror 40 micrometers (1.6 thousandths of an inch) towards the focal plane and tilting the primary mirror 0.0072 degree. On May 13, 2009, at 00:01 UTC, Kepler successfully completed its commissioning phase and began its search for planets around other stars. On June 19, 2009,
18354-482: Was announced that two volunteers from the Planet Hunters initiative had discovered a novel Neptune -like planet which is part of a four star double binary system, orbiting one of the pairs of stars while the other pair of stars orbits at a distance of around 1000 AU. This is the first planet discovered to have a stable orbit in such a complex stellar environment. The system is located 7200 light years away, and
18492-529: Was determined to be a low voltage power supply that provides power to the RAD750 processor. On January 12, 2010, one portion of the focal plane transmitted anomalous data, suggesting a problem with focal plane MOD-3 module, covering two out of Kepler's 42 CCDs . As of October 2010 , the module was described as "failed", but the coverage still exceeded the science goals. Kepler downlinked roughly twelve gigabytes of data about once per month. Kepler has
18630-407: Was developed allowing 10 ppm for stellar variability, roughly the value for the Sun. The obtained accuracy for this observation has a wide range, depending on the star and position on the focal plane, with a median of 29 ppm. Most of the additional noise appears to be due to a larger-than-expected variability in the stars themselves (19.5 ppm as opposed to the assumed 10.0 ppm), with
18768-467: Was part of NASA's Discovery Program of relatively low-cost science missions. The telescope's construction and initial operation were managed by NASA's Jet Propulsion Laboratory , with Ball Aerospace responsible for developing the Kepler flight system. In January 2006, the project's launch was delayed eight months because of budget cuts and consolidation at NASA. It was delayed again by four months in March 2006 due to fiscal problems. During this time,
18906-410: Was referred to simply as "the planet exterior to Uranus" or as "Le Verrier's planet". The first suggestion for a name came from Galle, who proposed the name Janus . In England, Challis put forward the name Oceanus . Claiming the right to name his discovery, Le Verrier quickly proposed the name Neptune for this new planet, though falsely stating that this had been officially approved by
19044-483: Was revisited with the colour normalised over time, most comprehensively in late 2023. Neptune's magnetosphere consists of a magnetic field that is strongly tilted relative to its rotational axis at 47° and offset of at least 0.55 radius (~13,500 km) from the planet's physical centre—resembling Uranus's magnetosphere. Before the arrival of Voyager 2 to Neptune, it was hypothesised that Uranus's sideways rotation caused its tilted magnetosphere. In comparing
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