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50-408: The June Boötids (shower #170 JBO) are a meteor shower occurring every year between 22 June and 2 July that peaks around June 27. In most years their activity is weak, with a zenithal hourly rate (ZHR) of only 1 or 2. However, occasional outbursts have been seen, with the outburst of 1916 drawing attention to the previously unrecorded meteor shower. The most recent outburst occurred in 1998, when

100-715: A Greek or Roman letter assigned that is close to the radiant position at the peak of the shower, whereby the grammatical declension of the Latin possessive form is replaced by "id" or "ids." Hence, meteors radiating from near the star Delta Aquarii (declension "-i") are called the Delta Aquariids . The International Astronomical Union's Task Group on Meteor Shower Nomenclature and the IAU's Meteor Data Center keep track of meteor shower nomenclature and which showers are established. A meteor shower results from an interaction between

150-488: A cloud of particles in space. Work continued, yet coming to understand the annual nature of showers though the occurrences of storms perplexed researchers. The actual nature of meteors was still debated during the 19th century. Meteors were conceived as an atmospheric phenomenon by many scientists ( Alexander von Humboldt , Adolphe Quetelet , Julius Schmidt ) until the Italian astronomer Giovanni Schiaparelli ascertained

200-438: A family of asteroids that move at low inclination and are close to the 3:1 mean-motion resonance with Jupiter. These were the first CM chondrites to be recovered from near the surface of the original parent body before it broke up, creating the asteroid family. Half a year later, in the evening of October 17, 2012, a bright fireball was seen near San Francisco. The first Novato meteorite , an L6 type chondrite fragmental breccia,

250-485: A likely impactor. When the final trajectory showed that meteorites would have fallen over land in Normandy, France, Jenniskens joined Francois Colas of IMCCE/Paris Observatory and other researchers and citizen scientists of FRIPON/Vigie-Ciel and guided the group to their first recovery of a 95g meteorite later that day. The next day, Jenniskens found the second meteorite, with a mass of 3 gram, the location of which verified

300-413: A mission to study the destructive entry of ESA's Automated Transfer Vehicle Jules Verne on 29 September 2008, Orbital ATK's Cygnus OA6 reentry on 22 June 2016, and the spectacular daytime re-entry of space debris object WT1190F near Sri-Lanka to practice a future observation of an impacting asteroid. In 2023, small asteroid 2023 CX1 was spotted in space and four hours prior to impact announced as

350-558: A mostly dormant comet. Examples are the Quadrantids and Geminids , which originated from a breakup of asteroid-looking objects, (196256) 2003 EH 1 and 3200 Phaethon , respectively, about 500 and 1000 years ago. The fragments tend to fall apart quickly into dust, sand, and pebbles and spread out along the comet's orbit to form a dense meteoroid stream, which subsequently evolves into Earth's path. Shortly after Whipple predicted that dust particles traveled at low speeds relative to

400-461: A planet, such as Earth, and streams of debris from a comet . Comets can produce debris by water vapor drag, as demonstrated by Fred Whipple in 1951, and by breakup. Whipple envisioned comets as "dirty snowballs," made up of rock embedded in ice, orbiting the Sun . The "ice" may be water , methane , ammonia , or other volatiles , alone or in combination. The "rock" may vary in size from a dust mote to

450-488: A shower component called a filament. A second effect is a close encounter with a planet. When the meteoroids pass by Earth, some are accelerated (making wider orbits around the Sun), others are decelerated (making shorter orbits), resulting in gaps in the dust trail in the next return (like opening a curtain, with grains piling up at the beginning and end of the gap). Also, Jupiter's perturbation can dramatically change sections of

500-494: A small boulder. Dust mote sized solids are orders of magnitude more common than those the size of sand grains, which, in turn, are similarly more common than those the size of pebbles, and so on. When the ice warms and sublimates, the vapor can drag along dust, sand, and pebbles. Each time a comet swings by the Sun in its orbit , some of its ice vaporizes, and a certain number of meteoroids will be shed. The meteoroids spread out along

550-621: A team from the University of Khartoum in Sudan that recovered fragments of asteroid 2008 TC3 in the Nubian Desert , marking the first time meteorite fragments had been found from an object that was previously tracked in outer space before hitting Earth. Since October 2010, Jenniskens has developed the global Cameras for All-Sky Meteor Surveillance (CAMS) project to map our meteor showers. Meteor showers are detected by triangulating

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600-464: Is the Perseids , which peak on 12 August of each year at over one meteor per minute. NASA has a tool to calculate how many meteors per hour are visible from one's observing location. The Leonid meteor shower peaks around 17 November of each year. The Leonid shower produces a meteor storm, peaking at rates of thousands of meteors per hour. Leonid storms gave birth to the term meteor shower when it

650-465: The Genesis (September 2004), Stardust (January 2006), and Hayabusa (June 2010) sample return capsules. The beautiful reentry of JAXA's Hayabusa probe over Australia on 13 June 2010 also included the disintegrating main spacecraft. These airborne missions studied what physical conditions the protective heat shield endured during the reentry before being recovered. More recently, Jenniskens led

700-505: The Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE). Because meteor shower particles are all traveling in parallel paths and at the same velocity, they will appear to an observer below to radiate away from a single point in the sky. This radiant point is caused by the effect of perspective , similar to parallel railroad tracks converging at a single vanishing point on the horizon. Meteor showers are normally named after

750-458: The 1995 Alpha Monocerotids outburst from dust trails. In anticipation of the 1999 Leonid storm, Robert H. McNaught , David Asher , and Finland's Esko Lyytinen were the first to apply this method in the West. In 2006 Jenniskens published predictions for future dust trail encounters covering the next 50 years. Jérémie Vaubaillon continues to update predictions based on observations each year for

800-422: The 1995 alpha Monocerotids , and from earlier not widely known identifications of past Earth storms. Over more extended periods, the dust trails can evolve in complicated ways. For example, the orbits of some repeating comets, and meteoroids leaving them, are in resonant orbits with Jupiter or one of the other large planets – so many revolutions of one will equal another number of the other. This creates

850-553: The 1995 Alpha Monocerotids meteor outburst (with members of the Dutch Meteor Society), proving that "stars fell like rain at midnight" because the dust trails of long-period comets wander on occasion in Earth's path. His research also includes artificial meteors. Jenniskens is the principal investigator of NASA's Genesis and Stardust Entry Observing Campaigns to study the fiery return from interplanetary space of

900-570: The International Astronomical Union's list of meteor showers. Any other Solar System body with a reasonably transparent atmosphere can also have meteor showers. As the Moon is in the neighborhood of Earth it can experience the same showers, but will have its own phenomena due to its lack of an atmosphere per se , such as vastly increasing its sodium tail . NASA now maintains an ongoing database of observed impacts on

950-492: The January 3, 2008, Quadrantids . Jenniskens identified several important mechanisms of how our meteor showers originate. Since 2003, Jenniskens identified the Quadrantids parent body 2003 EH 1 , and several others, as new examples of how fragmenting comets are the dominant source of meteor showers . These objects are now recognized as the main source of our zodiacal dust cloud . Before that, he predicted and observed

1000-489: The Sun ;– while more massive objects (responsible for bolides or fireballs ) will tend to be affected less by radiation pressure. This makes some dust trail encounters rich in bright meteors, others rich in faint meteors. Over time, these effects disperse the meteoroids and create a broader stream. The meteors we see from these streams are part of annual showers , because Earth encounters those streams every year at much

1050-520: The University of Khartoum. The search of the impact zone began on December 6, 2008, and turned up 24 pounds (11 kg) of rocks in about 600 fragments. This also proved the first well documented recovery of many different meteorite types from a single fall. The next biggest impact over land occurred in California's gold country on April 22, 2012. One of the fragments landed at Sutter's Mill,

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1100-572: The ZHR reached 100. The meteor shower occurs when the Earth crosses the orbit of Comet Pons-Winnecke , a short-period comet which orbits the Sun about every 6.3 years. They are very slow meteors making atmospheric entry at 14 km/s. This meteoroid-, meteor-, or meteorite-related article is a stub . You can help Misplaced Pages by expanding it . Meteor shower A meteor shower in August 1583

1150-570: The anticipated Leonid shower return of 1898 and 1899. Meteor storms were expected, but the final calculations showed that most of the dust would be far inside Earth's orbit. The same results were independently arrived at by Adolf Berberich of the Königliches Astronomisches Rechen Institut (Royal Astronomical Computation Institute) in Berlin, Germany. Although the absence of meteor storms that season confirmed

1200-590: The book Meteor Showers and their Parent Comets, published in 2006 and Atlas of Earth’s Meteor Showers, published in 2023. He is past president of Commission 22 of the International Astronomical Union (2012–2015) and was chair of the Working Group on Meteor Shower Nomenclature (2006–2012) after it was first established. Asteroid 42981 Jenniskens is named in his honor. In 2008, Jenniskens, together with Muawia Shaddad, led

1250-663: The calculations, the advance of much better computing tools was needed to arrive at reliable predictions. In 1981, Donald K. Yeomans of the Jet Propulsion Laboratory reviewed the history of meteor showers for the Leonids and the history of the dynamic orbit of Comet Tempel-Tuttle. A graph from it was adapted and re-published in Sky and Telescope . It showed relative positions of the Earth and Tempel-Tuttle and marks where Earth encountered dense dust. This showed that

1300-561: The comet, Milos Plavec was the first to offer the idea of a dust trail , when he calculated how meteoroids, once freed from the comet, would drift mostly in front of or behind the comet after completing one orbit. The effect is simple celestial mechanics  – the material drifts only a little laterally away from the comet while drifting ahead or behind the comet because some particles make a wider orbit than others. These dust trails are sometimes observed in comet images taken at mid infrared wavelengths (heat radiation), where dust particles from

1350-501: The constellation from which the meteors appear to originate. This "fixed point" slowly moves across the sky during the night due to the Earth turning on its axis, the same reason the stars appear to slowly march across the sky. The radiant also moves slightly from night to night against the background stars (radiant drift) due to the Earth moving in its orbit around the Sun. See IMO Meteor Shower Calendar 2017 ( International Meteor Organization ) for maps of drifting "fixed points." When

1400-401: The dust trail, especially for a short period comets, when the grains approach the giant planet at their furthest point along the orbit around the Sun, moving most slowly. As a result, the trail has a clumping , a braiding or a tangling of crescents , of each release of material. The third effect is that of radiation pressure which will push less massive particles into orbits further from

1450-436: The entire trajectory of the comet to form a meteoroid stream, also known as a "dust trail" (as opposed to a comet's "gas tail" caused by the tiny particles that are quickly blown away by solar radiation pressure). Recently, Peter Jenniskens has argued that most of our short-period meteor showers are not from the normal water vapor drag of active comets, but the product of infrequent disintegrations, when large chunks break off

1500-597: The event most accurately. After spending the last weeks of 1833 collecting information, he presented his findings in January 1834 to the American Journal of Science and Arts , published in January–April 1834, and January 1836. He noted the shower was of short duration and was not seen in Europe , and that the meteors radiated from a point in the constellation of Leo . He speculated the meteors had originated from

1550-475: The extent of the glass damage. Traffic video records were collected to map the shock wave arrival times. In order to determine the meteoroid entry speed and angle, star background calibration images were taken and shadow obstacle dimensions were measured at sites where video cameras recorded the fireball and its shadows. Eyewitnesses were interviewed to learn about injuries, heat sensations, sunburn, smells and where meteorites were found. Meteorites found shortly after

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1600-649: The fall from video records to an area in the Central Kalahari Game Reserve. Moses and Jenniskens then joined Alexander Proyer of BUIST and Mohutsiwa Gabadirwe of the Botswana Geoscience Institute in a search expedition, which led to the recovery of an 18 gram fragment on June 23, 2018. Twenty-two more meteorites were found in October that year. In 2021, the results from the international 2018 LA meteorite consortium study

1650-427: The meteoroids are mostly behind and outside the path of the comet, but paths of the Earth through the cloud of particles resulting in powerful storms were very near paths of nearly no activity. In 1985, E. D. Kondrat'eva and E. A. Reznikov of Kazan State University first correctly identified the years when dust was released which was responsible for several past Leonid meteor storms. In 1995, Peter Jenniskens predicted

1700-466: The meteoroids due to increased distance from the sun should marginally decrease meteor brightness. This is somewhat balanced because the slower descent means that Martian meteors have more time to ablate. On March 7, 2004, the panoramic camera on Mars Exploration Rover Spirit recorded a streak which is now believed to have been caused by a meteor from a Martian meteor shower associated with comet 114P/Wiseman-Skiff . A strong display from this shower

1750-519: The moon maintained by the Marshall Space Flight Center whether from a shower or not. Many planets and moons have impact craters dating back large spans of time. But new craters, perhaps even related to meteor showers are possible. Mars, and thus its moons, is known to have meteor showers. These have not been observed on other planets as yet but may be presumed to exist. For Mars in particular, although these are different from

1800-444: The moving radiant is at the highest point, it will reach the observer's sky that night. The Sun will be just clearing the eastern horizon. For this reason, the best viewing time for a meteor shower is generally slightly before dawn — a compromise between the maximum number of meteors available for viewing and the brightening sky, which makes them harder to see. Meteor showers are named after the nearest constellation, or bright star with

1850-673: The objects in the Solar System with an atmosphere: Mercury, Venus, Saturn's moon Titan , Neptune's moon Triton , and Pluto . Peter Jenniskens Petrus Matheus Marie (Peter) Jenniskens (born 1962 in Meterik ) is a Dutch - American astronomer and a senior research scientist at the Carl Sagan Center of the SETI Institute and at NASA Ames Research Center. He is an expert on meteor showers , and wrote

1900-401: The ones seen on Earth because of the different orbits of Mars and Earth relative to the orbits of comets. The Martian atmosphere has less than one percent of the density of Earth's at ground level, at their upper edges, where meteoroids strike; the two are more similar. Because of the similar air pressure at altitudes for meteors, the effects are much the same. Only the relatively slower motion of

1950-446: The path of meteors recorded in a low-light video camera surveillance of the night sky displayed at meteorshowers .seti .org . Jenniskens is the principal investigator of NASA's Leonid Multi-Instrument Aircraft Campaign (Leonid MAC), a series of four airborne missions that fielded modern instrumental techniques to study the 1998 - 2002 Leonids meteor storms. These missions helped develop meteor storm prediction models, detected

2000-415: The previous return to the Sun are spread along the orbit of the comet (see figures). The gravitational pull of the planets determines where the dust trail would pass by Earth orbit, much like a gardener directing a hose to water a distant plant. Most years, those trails would miss the Earth altogether, but in some years, the Earth is showered by meteors. This effect was first demonstrated from observations of

2050-412: The relation between meteors and comets in his work "Notes upon the astronomical theory of the falling stars" ( 1867 ). In the 1890s, Irish astronomer George Johnstone Stoney (1826–1911) and British astronomer Arthur Matthew Weld Downing (1850–1917) were the first to attempt to calculate the position of the dust at Earth's orbit. They studied the dust ejected in 1866 by comet 55P/Tempel-Tuttle before

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2100-414: The same rate. When the meteoroids collide with other meteoroids in the zodiacal cloud , they lose their stream association and become part of the "sporadic meteors" background. Long since dispersed from any stream or trail, they form isolated meteors, not a part of any shower. These random meteors will not appear to come from the radiant of the leading shower. In most years, the most visible meteor shower

2150-669: The signature of organic matter in the wake of meteors as a potential precursor to origin-of-life chemistry, and discovered many new aspects of meteor radiation. More recent meteor shower missions include the Aurigid Multi-Instrument Aircraft Campaign (Aurigid MAC), which studied a rare September 1, 2007, outburst of Aurigids from long-period comet C/1911 N1 (Kiess), and the Quadrantid Multi-Instrument Aircraft Campaign (Quadrantid MAC), which studied

2200-473: The very site where gold was first discovered in 1848 that led to the California Gold Rush. Jenniskens found one of three fragments of this CM chondrite on April 24, before rains hit the area. The rapid recovery was made possible because Doppler weather radar detected the falling meteorites. A consortium study led by Jenniskens traced these meteorites back to a source region in the asteroid belt:

2250-497: The wind drift to which small meteorites were exposed. This established the location of the meteorite strewn field. In subsequent weeks, over 20 more meteorites were found with masses in the range 2g to 350g. In 2018, a second asteroid 2018 LA was spotted in space and tracked to an impact over land. Working with Oliver Moses of the Okavango Research Institute of the University of Maun, Jenniskens triangulated

2300-606: Was expected on December 20, 2007. Other showers speculated about are a "Lambda Geminid" shower associated with the Eta Aquariids of Earth ( i.e. , both associated with Comet 1P/Halley ), a "Beta Canis Major" shower associated with Comet 13P/Olbers , and "Draconids" from 5335 Damocles . Isolated massive impacts have been observed at Jupiter: The 1994 Comet Shoemaker–Levy 9 which formed a brief trail as well, and successive events since then (see List of Jupiter events .) Meteors or meteor showers have been discussed for most of

2350-652: Was first realised that, during the November 1833 storm, the meteors radiated from near the star Gamma Leonis. The last Leonid storms were in 1999, 2001 (two), and 2002 (two). Before that, there were storms in 1767, 1799, 1833, 1866, 1867, and 1966. When the Leonid shower is not storming , it is less active than the Perseids. See the Infographics on Meteor Shower Calendar-2021 on the right. Official names are given in

2400-465: Was found by Novato resident Lisa Webber following Jenniskens' publication of the trajectory of the fireball from video recorded by stations of his Cameras for Allsky Meteor Surveillance project (CAMS). Three weeks after the February 15, 2013, Chelyabinsk meteor , Jenniskens participated in a Russian Academy of Sciences fact finding mission to Chelyabinsk Oblast. Over 50 villages were visited to map

2450-427: Was published, tracing the fragments of asteroid 2018 LA to an impact crater on Vesta. The recovery of fragments of asteroid 2008 TC 3 marked the first time fragments had been found from an object that was previously tracked in outer space before hitting Earth. This search was led by Peter Jenniskens and Muawia Shaddad of the University of Khartoum in Sudan , and carried out with help from students and staff of

2500-622: Was recorded in the Timbuktu manuscripts . In the modern era, the first great meteor storm was the Leonids of November 1833. One estimate is a peak rate of over one hundred thousand meteors an hour, but another, done as the storm abated, estimated more than two hundred thousand meteors during the 9 hours of the storm, over the entire region of North America east of the Rocky Mountains . American Denison Olmsted (1791–1859) explained

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