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121-468: Vega , Lyra's brightest star, is one of the brightest stars in the night sky , and forms a corner of the famed Summer Triangle asterism . Beta Lyrae is the prototype of a class of binary stars known as Beta Lyrae variables . These binary stars are so close to each other that they become egg-shaped and material flows from one to the other. Epsilon Lyrae , known informally as the Double Double,

242-467: A Delta Scuti variable . This is a category of stars that oscillate in a coherent manner, resulting in periodic pulsations in the star's luminosity. Although Vega fits the physical profile for this type of variable, other observers have found no such variation. Thus the variability was thought to possibly be the result of systematic errors in measurement. However, a 2007 article surveyed these and other results, and concluded that "A conservative analysis of

363-628: A circumstellar disk of dust . This dust is likely to be the result of collisions between objects in an orbiting debris disk , which is analogous to the Kuiper belt in the Solar System . Stars that display an infrared excess due to dust emission are termed Vega-like stars. Observations by the James Webb Space Telescope show that the disk is exceptionally smooth, with no evidence of shaping by massive planets, though there

484-448: A convection zone about the core that evenly distributes the 'ash' from the fusion reaction within the core region. The overlying atmosphere is in radiative equilibrium . This is in contrast to the Sun, which has a radiation zone centered on the core with an overlying convection zone. The energy flux from Vega has been precisely measured against standard light sources. At 5,480 Å ,

605-416: A nuclear fusion process that combines protons to form helium nuclei through intermediary nuclei of carbon, nitrogen and oxygen. This process becomes dominant at a temperature of about 17 million K, which is slightly higher than the core temperature of the Sun, but is less efficient than the Sun's proton–proton chain fusion reaction. The CNO cycle is highly temperature sensitive, which results in

726-412: A red dwarf and a white dwarf . Originally classified as a VY Sculptoris star due to spending most time at maximum brightness, since around 1979 the system has been dominantly at minimum brightness, with periodic outbursts. Its nature is still not fully understood. Another outbursting star is AY Lyrae , an SU Ursae Majoris -type dwarf nova that has undergone several superoutbursts . Of the same type

847-583: A vertex of a widely spaced asterism called the Summer Triangle , which consists of Vega plus the two first-magnitude stars Altair , in Aquila , and Deneb in Cygnus . This formation is the approximate shape of a right triangle , with Vega located at its right angle . The Summer Triangle is recognizable in the northern skies for there are few other bright stars in its vicinity. Astrophotography ,

968-438: A "superficially normal" star. The final star forming the lyre's figure is Sheliak ( Beta Lyrae ), also a binary composed of a blue bright giant and an early B-type star. In this case, the stars are so close together that the larger giant is overflowing its Roche lobe and transferring material to the secondary, forming a semidetached system. The secondary, originally the less massive of the two, has accreted so much mass that it

1089-503: A 1% chance of being a false positive. Considering the amplitude of the signal, the authors estimated a minimum mass of 21.9 ± 5.1 Earth masses, but considering the very oblique rotation of Vega itself of only 6.2° from Earth's perspective, the planet may be aligned to this plane as well, giving it an actual mass of 203 ± 47 Earth masses. The researchers also detected a faint 196.4 +1.6 −1.9 -day signal which could translate to 80 ± 21 Earth masses ( 740 ± 190 at 6.2° inclination) but

1210-425: A faint star was recently found to orbit component C as well, for a total of five stars. In contrast to Zeta and Epsilon Lyrae, Delta Lyrae is an optical double , with the two stars simply lying along the same line of sight east of Zeta. The brighter and closer of the two, Delta Lyrae , is a 4th-magnitude red bright giant that varies semiregularly by around 0.2 magnitudes with a dominant period of 79 days, while

1331-488: A lower frequency (toward the red), or to a higher frequency (toward the blue) if the motion is toward the Earth. Thus the velocity can be measured from the amount of shift of the star's spectrum. Precise measurements of this blueshift give a value of −13.9 ± 0.9 km/s . The minus sign indicates a relative motion toward the Earth. Motion transverse to the line of sight causes the position of Vega to shift with respect to

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1452-482: A magnitude every 2.18 days during the primary eclipse. Both components are main-sequence stars, the primary being late F-type and the secondary late G-type . The system was one of the first main-sequence eclipsing binaries containing G-type star to have its properties known as well as the better-studied early-type eclipsing binaries. At the very northernmost edge of the constellation is the even fainter V361 Lyrae , an eclipsing binary that does not easily fall into one of

1573-572: A period of 120 days. Also just visible to the naked eye is the peculiar classical Cepheid V473 Lyrae . It is unique in that it is the only known Cepheid in the Milky Way to undergo periodic phase and amplitude changes, analogous to the Blazhko effect in RR Lyrae stars. At 1.5 days, its period was the shortest known for a classical Cepheid at the time of its discovery. W and S Lyrae are two of

1694-451: A planet with <6 M E at 65 AU would introduce interior asymetric structures that are not seen in the disk of Vega. Any gap-opening planet would need to be less massive. Additionally the inner edge of the inner disk was inferred to be 3-5 AU. Vega shows also evidence for hot infrared excess at the sub-AU region. The inner boundary of the warm debris might indicate that there is a Neptune -mass planet inside, shepherding it. The name

1815-399: A planetary system still undergoing formation. Determining the nature of the planet has not been straightforward; a 2002 paper hypothesizes that the clumps are caused by a roughly Jupiter-mass planet on an eccentric orbit . Dust would collect in orbits that have mean-motion resonances with this planet—where their orbital periods form integer fractions with the period of the planet—producing

1936-510: A planetary system. The disk was also observed with ALMA in 2020, the LMT in 2022 and with Hubble STIS and JWST MIRI in 2024. The ALMA image did resolve the outer disk for the first time. The Hubble observation is the first image of the disk in scattered light and found an outer halo made up of small dust grains. JWST observations also detected the Halo, the outer disk and for the first time

2057-407: A region filled with young, hot, blue stars. Astronomers do not know if the collision was simply a glancing blow or a prelude to a full-on merger, which would end with the two galaxies incorporated into one larger, probably elliptical galaxy . A remarkable long-duration gamma-ray burst was GRB 050525A , which flared in 2005. The afterglow re-brightened at 33 minutes after the original burst, only

2178-409: A relatively flat electromagnetic spectrum in the visual region—wavelength range 350–850 nanometers , most of which can be seen with the human eye—so the flux densities are roughly equal; 2,000– 4,000  Jy . However, the flux density of Vega drops rapidly in the infrared , and is near 100 Jy at 5  micrometers . Photometric measurements of Vega during the 1930s appeared to show that

2299-501: A second gap between the inner disk and the hot dust around the star. This hot infrared excess lies within about 0.2 AU or closer and is made up of small grains, like graphite and iron and manganese oxides, which was previously verified. Observations from the James Clerk Maxwell Telescope in 1997 revealed an "elongated bright central region" that peaked at 9″ ( 70 AU ) to the northeast of Vega. This

2420-465: A slight angle. It can be found halfway between Gamma Lyrae and Beta Lyrae. Another planetary nebula in Lyra is Abell 46 . The central star, V477 Lyrae , is an eclipsing post-common-envelope binary , consisting of a white dwarf primary and an oversized secondary component due to recent accretion. The nebula itself is of relatively low surface brightness compared to the central star, and is undersized for

2541-586: A smaller orbit. Using a coronagraph on the Subaru Telescope in Hawaii in 2005, astronomers were able to further constrain the size of a planet orbiting Vega to no more than 5–10 times the mass of Jupiter. The issue of possible clumps in the debris disc was revisited in 2007 using newer, more sensitive instrumentation on the Plateau de Bure Interferometer . The observations showed that the debris ring

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2662-450: A solid, rocky, earth-like planet. The exoplanets are 1.6 and 1.4 times the diameter of Earth respectively, with their star Kepler-62 at a distance of 1,200 light-years. Vega Vega is the brightest star in the northern constellation of Lyra . It has the Bayer designation α Lyrae , which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr . This star

2783-469: A star is located along the Earth's axis of rotation, it will remain in the same position and thus is called a pole star . The direction of the Earth's axis of rotation gradually changes over time in a process known as the precession of the equinoxes . A complete precession cycle requires 25,770 years, during which time the pole of the Earth's rotation follows a circular path across the celestial sphere that passes near several prominent stars. At present

2904-411: A star's parallax was Friedrich G. W. von Struve , when he announced a value of 0.125 arcsecond ( 0.125″ ) for Vega. Friedrich Bessel was skeptical about Struve's data, and, when Bessel published a parallax of 0.314″ for the star system 61 Cygni , Struve revised his value for Vega's parallax to nearly double the original estimate. This change cast further doubt on Struve's data. Thus most astronomers at

3025-436: A wide binary star visible in binoculars, consisting of an Am star and an F-type subgiant . The Am star has an additional close companion, bringing the total number of stars in the system to three. Epsilon is a more famous wide binary that can even be separated by the naked eye under excellent conditions. Both components are themselves close binaries which can be seen with telescopes to consist of A- and F-type stars, and

3146-401: Is 12.9 km/s . Although Vega is at present only the fifth-brightest star in the night sky, the star is slowly brightening as proper motion causes it to approach the Sun. Vega will make its closest approach in an estimated 264,000 years at a perihelion distance of 13.2 ly (4.04 pc). Based on this star's kinematic properties, it appears to belong to a stellar association called

3267-413: Is 2.362 ± 0.012 solar radii , while the equatorial radius is 2.818 ± 0.013 solar radii. ) From the Earth, this bulge is being viewed from the direction of its pole, producing the overly large radius estimate. The local surface gravity at the poles is greater than at the equator, which produces a variation in effective temperature over the star: the polar temperature is near 10,000  K , while

3388-522: Is 200 ± 100 million years , and they have an average space velocity of 16.5 km/s . One of the early results from the Infrared Astronomy Satellite (IRAS) was the discovery of excess infrared flux coming from Vega, beyond what would be expected from the star alone. This excess was measured at wavelengths of 25, 60 and 100  μm , and came from within an angular radius of 10 arcseconds ( 10″ ) centered on

3509-456: Is 327.78 mas/y , which results in angular movement of a degree every 11,000 years . In the galactic coordinate system , the space velocity components of Vega are (U, V, W) = ( −16.1 ± 0.3 , −6.3 ± 0.8 , −7.7 ± 0.3 ) km/s , for a net space velocity of 19 km/s . The radial component of this velocity—in the direction of the Sun—is −13.9 km/s , while the transverse velocity

3630-408: Is Gliese 758 . The sunlike primary star has a brown dwarf companion, the coldest to have been imaged around a sunlike star in thermal light when it was discovered in 2009. Only slightly farther away is V478 Lyrae , an eclipsing RS Canum Venaticorum variable whose primary star shows active starspot activity. One of the most peculiar systems in Lyra is MV Lyrae , a nova-like star consisting of

3751-422: Is HD 178911 , a triple system consisting of a close binary and a visually separable sunlike star. The sunlike star has a planet with over 6 Jupiter masses discovered in 2001, the second found in a triple system after that of 16 Cygni . One of the most-studied exoplanets in the night sky is TrES-1b , in orbit around the star GSC 02652-01324 . Detected from a transit of its parent star, the planet has around 3/4

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3872-431: Is V344 Lyrae , notable for an extremely short period between superoutbursts coupled with one of the highest amplitudes for such a period. The true nova HR Lyrae flared in 1919 to a maximum magnitude of 6.5, over 9.5 magnitudes higher than in quiescence. Some of its characteristics are similar to those of recurring novae . M57 , also known as the "Ring Nebula" and NGC 6720, at a distance of 2,550 light-years from Earth

3993-449: Is relatively close at only 25 light-years (7.7 parsecs ) from the Sun , and one of the most luminous stars in the Sun's neighborhood . It is the fifth-brightest star in the night sky , and the second-brightest star in the northern celestial hemisphere , after Arcturus . Vega has been extensively studied by astronomers, leading it to be termed "arguably the next most important star in

4114-465: Is 3 × 10 times the mass of the Earth (around 7.5 times more massive than the asteroid belt ). Production of the dust would require collisions between asteroids in a population corresponding to the Kuiper Belt around the Sun. Thus the dust is more likely created by a debris disk around Vega, rather than from a protoplanetary disk as was earlier thought. The inner boundary of the debris disk

4235-538: Is a complex multiple star system. Lyra also hosts the Ring Nebula , the second-discovered and best-known planetary nebula . In Greek mythology , Lyra represents the lyre of Orpheus . Orpheus's music was said to be so great that even inanimate objects such as rocks could be charmed. Joining Jason and the Argonauts , his music was able to quell the voices of the dangerous Sirens , who sang tempting songs to

4356-408: Is a hole in the center of the disk with a radius of no less than 80 AU . Following the discovery of an infrared excess around Vega, other stars have been found that display a similar anomaly that is attributable to dust emission. As of 2002, about 400 of these stars have been found, and they have come to be termed "Vega-like" or "Vega-excess" stars. It is believed that these may provide clues to

4477-479: Is a non- SI unit measure of solid angle . Other denotations include sq. deg. and (°) . Just as degrees are used to measure parts of a circle, square degrees are used to measure parts of a sphere . Analogous to one degree being equal to ⁠ π / 180 ⁠  radians, a square degree is equal to ( ⁠ π / 180 ⁠ ) steradians (sr), or about ⁠ 1 / 3283 ⁠  sr or about 3.046 × 10  sr . The whole sphere has

4598-459: Is a rapidly rotating star that is being viewed from the direction of its pole of rotation. Observations by the CHARA array in 2005–06 confirmed this deduction. The pole of Vega—its axis of rotation—is inclined no more than five degrees from the line-of-sight to the Earth. At the high end of estimates for the rotation velocity for Vega is 236.2 ± 3.7 km/s along the equator, much higher than

4719-441: Is about 40 times the Sun's. Because it is rotating rapidly, approximately once every 16.5 hours, and seen nearly pole-on, its apparent luminosity, calculated assuming it was the same brightness all over, is about 57 times the Sun's. If Vega is variable, then it may be a Delta Scuti type with a period of about 0.107 day. Most of the energy produced at Vega's core is generated by the carbon–nitrogen–oxygen cycle ( CNO cycle ),

4840-498: Is also a variable star —that is, a star whose brightness fluctuates. It is rotating rapidly with a speed of 236 km/s at the equator. This causes the equator to bulge outward due to centrifugal effects, and, as a result, there is a variation of temperature across the star's photosphere that reaches a maximum at the poles. From Earth, Vega is observed from the direction of one of these poles. Based on observations of more infrared radiation than expected, Vega appears to have

4961-406: Is another star with an exoplanet discovered by Kepler; the planet is the smallest known extrasolar planet known as of February 2013. In April 2013, it was announced that of the five planets orbiting Kepler-62 , at least two— Kepler-62e and Kepler-62f —are within the boundaries of the habitable zone of that star, where scientists think liquid water could exist, and are both candidates for being

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5082-509: Is believed to be derived from the Arabic term Al Nesr al Waki النسر الواقع which appeared in the Al Achsasi al Mouakket star catalogue and was translated into Latin as Vultur Cadens , "the falling eagle/vulture". The constellation was represented as a vulture in ancient Egypt , and as an eagle or vulture in ancient India . The Arabic name then appeared in the western world in

5203-420: Is colored green; doubly ionized oxygen emits greenish-blue light. The hottest region, closest to the central star, appears blue because of emission from helium . The central star itself is a white dwarf with a temperature of 120,000 kelvins . In telescopes, the nebula appears as a visible ring with a green tinge; it is slightly elliptical because its three-dimensional shape is a torus or cylinder seen from

5324-431: Is no longer the case, as the apparent magnitude zero point is now commonly defined in terms of a particular numerically specified flux . This approach is more convenient for astronomers, since Vega is not always available for calibration and varies in brightness. The UBV photometric system measures the magnitude of stars through ultraviolet , blue and yellow filters, producing U , B and V values, respectively. Vega

5445-633: Is now substantially more massive, albeit smaller, than the primary, and is surrounded by a thick accretion disk . The plane of the orbit is aligned with Earth and the system thus shows eclipses , dropping nearly a full magnitude from its 3rd-magnitude baseline every 13 days, although its period is increasing by around 19 seconds per year. It is the prototype of the Beta Lyrae variables , eclipsing semidetached binaries of early spectral types in which there are no exact onsets of eclipses, but rather continuous changes in brightness. Another easy-to-spot variable

5566-461: Is on the far side of the river, the Milky Way . However, one day per year on the seventh day of the seventh month of the Chinese lunisolar calendar , magpies make a bridge so that Niulang and Zhinü can be together again for a brief encounter. The Japanese Tanabata festival, in which Vega is known as Orihime (織姫), is also based on this legend. Square degree A square degree ( deg )

5687-422: Is one of six A0V stars that were used to set the initial mean values for this photometric system when it was introduced in the 1950s. The mean magnitudes for these six stars were defined as: U − B = B − V = 0. In effect, the magnitude scale has been calibrated so that the magnitude of these stars is the same in the yellow, blue and ultraviolet parts of the electromagnetic spectrum . Thus, Vega has

5808-531: Is one of the best known planetary nebulae and the second to be discovered; its integrated magnitude is 8.8. It was discovered in 1779 by Antoine Darquier , 15 years after Charles Messier discovered the Dumbbell Nebula . Astronomers have determined that it is between 6,000 and 8,000 years old; it is approximately one light-year in diameter. The outer part of the nebula appears red in photographs because of emission from ionized hydrogen . The middle region

5929-430: Is one of the earliest exoplanets to be detected. A jovian-mass planet, it orbits in an eccentric orbit with a period of 390 days. A second planet closer to the star was discovered in 2011. Visible to the naked eye are HD 173416 , a yellow giant hosting a planet over twice the mass of Jupiter discovered in 2009; and HD 176051 , a low-mass binary star containing another high-mass planet. Just short of naked-eye visibility

6050-425: Is only marginally less abundant and sulfur abundance is about 50% of solar. On the other hand, Vega has only 10% to 30% of the solar abundance for most other major elements with barium and scandium below 10%. The unusually low metallicity of Vega makes it a weak Lambda Boötis star . However, the reason for the existence of such chemically peculiar, spectral class A0–F0 stars remains unclear. One possibility

6171-428: Is rapidly rotating may challenge some of the underlying assumptions that were based on it being spherically symmetric. With the viewing angle and rotation rate of Vega now better known, this will allow improved instrument calibrations. In astronomy, those elements with higher atomic numbers than helium are termed "metals". The metallicity of Vega's photosphere is only about 32% of the abundance of heavy elements in

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6292-400: Is roughly one billion years, a tenth of the Sun's. The current age of this star is about 455 million years, or up to about half its expected total main-sequence lifespan. After leaving the main sequence, Vega will become a class-M red giant and shed much of its mass, finally becoming a white dwarf . At present, Vega has more than twice the mass of the Sun and its bolometric luminosity

6413-405: Is significantly oblate like those two planets. When the radius of Vega was measured to high accuracy with an interferometer , it resulted in an unexpectedly large estimated value of 2.73 ± 0.01 times the radius of the Sun . This is 60% larger than the radius of the star Sirius, while stellar models indicated it should only be about 12% larger. However, this discrepancy can be explained if Vega

6534-526: Is smooth and symmetric. No evidence was found of the blobs reported earlier, casting doubts on the hypothesized giant planet. The smooth structure has been confirmed in follow-up observations by Hughes et al. (2012) and the Herschel Space Telescope . Although a planet has yet to be directly observed around Vega, the presence of a planetary system cannot yet be ruled out. Thus there could be smaller, terrestrial planets orbiting closer to

6655-439: Is some evidence that there may be one or more Neptune-mass planets closer to the star. α Lyrae ( Latinised to Alpha Lyrae ) is the star's Bayer designation . The traditional name Vega (earlier Wega ) comes from a loose transliteration of the Arabic word wāqi' ( Arabic : واقع ) meaning "falling" or "landing", via the phrase an-nasr al-wāqi' ( Arabic : النّسر الْواقع ), "the falling eagle". In 2016,

6776-467: Is that the chemical peculiarity may be the result of diffusion or mass loss, although stellar models show that this would normally only occur near the end of a star's hydrogen-burning lifespan. Another possibility is that the star formed from an interstellar medium of gas and dust that was unusually metal-poor. The observed helium to hydrogen ratio in Vega is 0.030 ± 0.005 , which is about 40% lower than

6897-403: Is the bright R Lyrae , north of the main asterism. Also known as 13 Lyrae, it is a 4th-magnitude red giant semiregular variable that varies by several tenths of a magnitude. Its periodicity is complex, with several different periods of varying lengths, most notably one of 46 days and one of 64 days. Even further north is FL Lyrae , a much fainter 9th-magnitude Algol variable that drops by half

7018-422: Is too faint to claim as a real signal with available data. Observations of the disk with JWST MIRI did find a very circular face-on disk. The morphology indicate that there is no planet more massive than Saturn beyond 10 AU. The disk has a gap at around 60 AU. Gap-opening planets are inferred for disks around other stars and the team tests this idea for Vega by running simulations. The simulations have shown that

7139-528: The Alfonsine tables , which were drawn up between 1215 and 1270 by order of King Alfonso X . Medieval astrolabes of England and Western Europe used the names Wega and Alvaca, and depicted it and Altair as birds. Among the northern Polynesian people, Vega was known as whetu o te tau , the year star. For a period of history it marked the start of their new year when the ground would be prepared for planting. Eventually this function became denoted by

7260-491: The CHARA array at Mt. Wilson in 2006 and the Infrared Optical Telescope Array at Mt. Hopkins in 2011, revealed evidence for an inner dust band around Vega. Originating within 8 AU of the star, this exozodiacal dust may be evidence of dynamical perturbations within the system. This may be caused by an intense bombardment of comets or meteors , and may be evidence for the existence of

7381-568: The Castor Moving Group . However, Vega may be much older than this group, so the membership remains uncertain. This group contains about 16 stars, including Alpha Librae , Alpha Cephei , Castor , Fomalhaut and Vega. All members of the group are moving in nearly the same direction with similar space velocities . Membership in a moving group implies a common origin for these stars in an open cluster that has since become gravitationally unbound. The estimated age of this moving group

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7502-597: The International Astronomical Union (IAU) organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Vega for this star. It is now so entered in the IAU Catalog of Star Names . Vega can often be seen near the zenith in

7623-632: The Pleiades . The Assyrians named this pole star Dayan-same, the "Judge of Heaven", while in Akkadian it was Tir-anna, "Life of Heaven". In Babylonian astronomy , Vega may have been one of the stars named Dilgan, "the Messenger of Light". To the ancient Greeks , the constellation Lyra was formed from the harp of Orpheus , with Vega as its handle. For the Roman Empire , the start of autumn

7744-628: The White Sands Missile Range . In 1983, Vega became the first star found to have a disk of dust. The Infrared Astronomical Satellite (IRAS) discovered an excess of infrared radiation coming from the star, and this was attributed to energy emitted by the orbiting dust as it was heated by the star. Vega's spectral class is A0V, making it a blue-tinged white main-sequence star that is fusing hydrogen to helium in its core. Since more massive stars use their fusion fuel more quickly than smaller ones, Vega's main-sequence lifetime

7865-484: The corona for this star must be very weak or non-existent. However, as the pole of Vega is facing Earth and a polar coronal hole may be present, confirmation of a corona as the likely source of the X-rays detected from Vega (or the region very close to Vega) may be difficult as most of any coronal X-rays would not be emitted along the line of sight. Using spectropolarimetry , a magnetic field has been detected on

7986-608: The photography of celestial objects, began in 1840 when John William Draper took an image of the Moon using the daguerreotype process. On 17 July 1850, Vega became the first star (other than the Sun) to be photographed, when it was imaged by William Bond and John Adams Whipple at the Harvard College Observatory , also with a daguerreotype. In August 1872, Henry Draper took a photograph of Vega's spectrum ,

8107-501: The photometric brightness scale and was one of the stars used to define the zero point for the UBV photometric system . Vega is only about a tenth of the age of the Sun, but since it is 2.1 times as massive, its expected lifetime is also one tenth of that of the Sun; both stars are at present approaching the midpoint of their main sequence lifetimes. Compared with the Sun, Vega has a lower abundance of elements heavier than helium . Vega

8228-460: The spectrum of this star has served as one of the stable anchor points by which other stars are classified. The distance to Vega can be determined by measuring its parallax shift against the background stars as the Earth orbits the Sun. Giuseppe Calandrelli noted stellar parallax in 1805-6 and came up with a 4-second value for the star which was a gross overestimate. The first person to publish

8349-595: The Argonauts. At one point, Orpheus married Eurydice , a nymph . While fleeing from an attack by Aristaeus , she stepped on a snake that bit her, killing her. To reclaim her, Orpheus entered the Underworld , where the music from his lyre charmed Hades , the god of the Underworld. Hades relented and let Orpheus bring Eurydice back, on the condition that he never once look back until outside. Unfortunately, near

8470-406: The Sun's atmosphere. (Compare this, for example, to a threefold metallicity abundance in the similar star Sirius as compared to the Sun.) For comparison, the Sun has an abundance of elements heavier than helium of about Z Sol  =  0.0172 ± 0.002 . Thus, in terms of abundances, only about 0.54% of Vega consists of elements heavier than helium. Nitrogen is slightly more abundant, oxygen

8591-406: The Sun. In 2015, bright starspots were detected on the star's surface—the first such detection for a normal A-type star , and these features show evidence of rotational modulation with a period of 0.68 day. Vega has a rotation period of 16.3 hours, much faster than the Sun's rotational period but similar to, and slightly slower than, those of Jupiter and Saturn . Because of that, Vega

8712-404: The Sun. This may be caused by the disappearance of a helium convection zone near the surface. Energy transfer is instead performed by the radiative process , which may be causing an abundance anomaly through diffusion. The radial velocity of Vega is the component of this star's motion along the line-of-sight to the Earth. Movement away from the Earth will cause the light from Vega to shift to

8833-416: The constellation is Vega (Alpha Lyrae), a main-sequence star of spectral type A0Va. Only 7.7 parsecs distant, Vega is a Delta Scuti variable , varying between magnitudes −0.02 and 0.07 over 0.2 days. On average, it is the second-brightest star of the northern hemisphere (after Arcturus ) and the fifth-brightest star in all, surpassed only by Arcturus, Alpha Centauri , Canopus , and Sirius . Vega

8954-405: The equatorial temperature is about 8,152 K . This large temperature difference between the poles and the equator produces a strong gravity darkening effect. As viewed from the poles, this results in a darker (lower-intensity) limb than would normally be expected for a spherically symmetric star. The temperature gradient may also mean that Vega has a convection zone around the equator, while

9075-415: The extreme east is RR Lyrae , the prototype of the large class of variables known as RR Lyrae variables , which are pulsating variables similar to Cepheids , but are evolved population II stars of spectral types A and F. Such stars are usually not found in a galaxy's thin disk , but rather in the galactic halo . Such stars serve as standard candles , and thus are a reliable way to calculate distances to

9196-495: The fainter Delta Lyrae is a spectroscopic binary consisting of a B-type primary and an unknown secondary. Both systems, however, have very similar radial velocities , and are the two brightest members of a sparse open cluster known as the Delta Lyrae cluster . South of Delta is Sulafat ( Gamma Lyrae ), a blue giant and the second-brightest star in the constellation. Around 190 parsecs distant, it has been referred to as

9317-449: The first discovered by the mission is Kepler-7b , an extremely low-density exoplanet with less than half the mass of Jupiter, yet nearly 1.5 times the radius. Almost as sparse is Kepler-8b , only slightly more massive and of a similar radius. The Kepler-20 system contains five known planets; three of them are only slightly smaller than Neptune , while the other two are some of the first Earth -sized exoplanets to be discovered. Kepler-37

9438-465: The first photograph of a star's spectrum showing absorption lines. Similar lines had already been identified in the spectrum of the Sun. In 1879, William Huggins used photographs of the spectra of Vega and similar stars to identify a set of twelve "very strong lines" that were common to this stellar category. These were later identified as lines from the Hydrogen Balmer series . Since 1943,

9559-428: The flux density is 3,650 Jy with an error margin of 2%. The visual spectrum of Vega is dominated by absorption lines of hydrogen; specifically by the hydrogen Balmer series with the electron at the n=2 principal quantum number . The lines of other elements are relatively weak, with the strongest being ionized magnesium , iron and chromium . The X-ray emission from Vega is very low, demonstrating that

9680-448: The foregoing results suggests that Vega is quite likely variable in the 1–2% range, with possible occasional excursions to as much as 4% from the mean". Also, a 2011 article affirms that "The long-term (year-to-year) variability of Vega was confirmed". Vega became the first solitary main-sequence star beyond the Sun known to be an X-ray emitter when in 1979 it was observed from an imaging X-ray telescope launched on an Aerobee 350 from

9801-503: The globular clusters in which they reside. RR Lyrae itself varies between magnitudes 7 and 8 while exhibiting the Blazhko effect . The easternmost star designated by Flamsteed , 19 Lyrae , is also a small-amplitude variable, an Alpha Canum Venaticorum variable with a period of just over one day. Another evolved star is the naked-eye variable XY Lyrae , a red bright giant just north of Vega that varies between 6th and 7th magnitudes over

9922-475: The inner disk. The infrared observations also showed a gap at 60 AU for the first time. The dust interior of the outer disk is consistent with dust being dragged by the Poynting-Robertson effect . The inner edge of the inner disk is hidden behind the coronagraph , but it was inferred to be 3-5 AU from photometry. The star is also surrounded by hot infrared excess, located at the sub-AU region, leaving

10043-491: The many Mira variables in Lyra. W varies between 7th and 12th magnitudes over approximately 200 days, while S, slightly fainter, is a silicate carbon star , likely of the J-type . Another evolved star is EP Lyrae , a faint RV Tauri variable and an "extreme example" of a post-AGB star. It and a likely companion are surrounded by a circumstellar disk of material. Rather close to Earth at a distance of only 16 parsecs (52 ly)

10164-406: The mass of Jupiter, yet orbits its parent star in only three days. The transits have been reported to have anomalies multiple times. Originally thought to be possibly due to the presence of an Earth-like planet, it is now accepted that the irregularities are due to a large starspot. Also discovered by the transit method is WASP-3b , with 1.75 times the mass of Jupiter. At the time of its discovery, it

10285-652: The mid-northern latitudes during the evening in the Northern Hemisphere summer. From mid-southern latitudes, it can be seen low above the northern horizon during the Southern Hemisphere winter. With a declination of +38.78°, Vega can only be viewed at latitudes north of 51° S . Therefore, it does not rise at all anywhere in Antarctica or in the southernmost part of South America, including Punta Arenas , Chile (53° S). At latitudes to

10406-416: The more distant background stars. Careful measurement of the star's position allows this angular movement, known as proper motion , to be calculated. Vega's proper motion is 202.03 ± 0.63  milliarcseconds (mas) per year in right ascension —the celestial equivalent of longitude —and 287.47 ± 0.54 mas/y in declination , which is equivalent to a change in latitude . The net proper motion of Vega

10527-455: The neighbouring constellation now known as Hercules was said to depict many different mythical figures, including Theseus, Orpheus, or the musician Thamyris . The proximity of these two constellations and Corona Borealis (perhaps a symbol of Theseus' royalty) could indicate that the three constellations were invented as a group. Vega and its surrounding stars are also treated as a constellation in other cultures. The area corresponding to Lyra

10648-400: The north of 51° N , Vega remains continuously above the horizon as a circumpolar star . Around July 1, Vega reaches midnight culmination when it crosses the meridian at that time. Complementarily, Vega swoops down and kisses the horizon at true North at midnight on Dec 31/Jan 1, as seen from 51° N. Each night the positions of the stars appear to change as the Earth rotates. However, when

10769-511: The observed (i.e. projected ) rotational velocity because Vega is seen almost pole-on. This is 88% of the speed that would cause the star to start breaking up from centrifugal effects. This rapid rotation of Vega produces a pronounced equatorial bulge, so the radius of the equator is 19% larger than the polar radius, compared to just under 11% for Saturn, the most oblate of the Solar System's planets. (The estimated polar radius of this star

10890-442: The order of 100 μm or less. To maintain this amount of dust in orbit around Vega, a continual source of replenishment would be required. A proposed mechanism for maintaining the dust was a disk of coalesced bodies that were in the process of collapsing to form a planet. Models fitted to the dust distribution around Vega indicate that it is a 120-astronomical-unit-radius circular disk viewed from nearly pole-on. In addition, there

11011-548: The origin of the Solar System . By 2005, the Spitzer Space Telescope had produced high-resolution infrared images of the dust around Vega. It was shown to extend out to 43″ ( 330 AU ) at a wavelength of 24 μm , 70″ ( 543 AU ) at 70 μm and 105″ ( 815 AU ) at 160 μm . These much wider disks were found to be circular and free of clumps, with dust particles ranging from 1– 50 μm in size. The estimated total mass of this dust

11132-418: The pole star is Polaris , but around 12,000 BCE the pole was pointed only five degrees away from Vega. Through precession, the pole will again pass near Vega around 14,000 CE. Vega is the brightest of the successive northern pole stars. In 210,000 years, Vega will become the brightest star in the night sky, and will peak in brightness in 290,000 years with an apparent magnitude of –0.81. This star lies at

11253-420: The primary's mass for reasons not yet fully understood. NGC 6791 is a cluster of stars in Lyra. It contains three age groups of stars: 4 billion year-old white dwarfs, 6 billion year-old white dwarfs and 8 billion year-old normal stars. NGC 6745 is an irregular spiral galaxy in Lyra that is at a distance of 208 million light-years. Several million years ago, it collided with a smaller galaxy, which created

11374-457: The remainder of the atmosphere is likely to be in almost pure radiative equilibrium . By the Von Zeipel theorem , the local luminosity is higher at the poles. As a result, if Vega were viewed along the plane of its equator instead of almost pole-on, then its overall brightness would be lower. As Vega had long been used as a standard star for calibrating telescopes , the discovery that it

11495-589: The result of a relatively recent breakup of a moderate-sized (or larger) comet or asteroid, which then further fragmented as the result of collisions between the smaller components and other bodies. This dusty disk would be relatively young on the time scale of the star's age, and it will eventually be removed unless other collision events supply more dust. Observations, first with the Palomar Testbed Interferometer by David Ciardi and Gerard van Belle in 2001 and then later confirmed with

11616-405: The resulting clumpiness. In 2003, it was hypothesized that these clumps could be caused by a roughly Neptune -mass planet having migrated from 40 to 65  AU over 56 million years, an orbit large enough to allow the formation of smaller rocky planets closer to Vega. The migration of this planet would likely require gravitational interaction with a second, higher-mass planet in

11737-409: The same magnitude is Eta Lyrae , a blue subgiant with a near-solar metal abundance. Also nearby is the faint HP Lyrae , a post-asymptotic giant branch (AGB) star that shows variability. The reason for its variability is still a mystery: first cataloged as an eclipsing binary, it was theorized to be an RV Tauri variable in 2002, but if so, it would be by far the hottest such variable discovered. In

11858-415: The sky after the Sun". Vega was the northern pole star around 12,000 BCE and will be so again around the year 13,727, when its declination will be +86° 14′. Vega was the first star other than the Sun to have its image and spectrum photographed. It was one of the first stars whose distance was estimated through parallax measurements. Vega has functioned as the baseline for calibrating

11979-441: The star by means of Poynting–Robertson drag . The latter is the result of radiation pressure creating an effective force that opposes the orbital motion of a dust particle, causing it to spiral inward. This effect is most pronounced for tiny particles that are closer to the star. Subsequent measurements of Vega at 193 μm showed a lower than expected flux for the hypothesized particles, suggesting that they must instead be on

12100-540: The star had a low-magnitude variability on the order of ±0.03 magnitude (around ±2.8% luminosity). This range of variability was near the limits of observational capability for that time, and so the subject of Vega's variability has been controversial. The magnitude of Vega was measured again in 1981 at the David Dunlap Observatory and showed some slight variability. Thus it was suggested that Vega showed occasional low-amplitude pulsations associated with

12221-415: The star. At the measured distance of Vega, this corresponded to an actual radius of 80  astronomical units (AU), where an AU is the average radius of the Earth's orbit around the Sun. It was proposed that this radiation came from a field of orbiting particles with a dimension on the order of a millimetre, as anything smaller would eventually be removed from the system by radiation pressure or drawn into

12342-490: The star. The inclination of planetary orbits around Vega is likely to be closely aligned to the equatorial plane of this star. From the perspective of an observer on a hypothetical planet around Vega, the Sun would appear as a faint 4.3-magnitude star in the Columba constellation. In 2021, a paper analyzing 10 years of spectra of Vega detected a candidate 2.43-day signal around Vega, statistically estimated to have only

12463-440: The star. The faintest stars visible to the unaided eye are sixth magnitude, while the brightest in the night sky, Sirius , is of magnitude −1.46. To standardize the magnitude scale, astronomers chose Vega and several similar stars and averaged their brightness to represent magnitude zero at all wavelengths. Thus, for many years, Vega was used as a baseline for the calibration of absolute photometric brightness scales. However, this

12584-409: The supreme deity instead. Dionysus then sent his followers to rip Orpheus apart. Ovid tells a rather different story, saying that women, in retribution for Orpheus's rejection of marriage offers, ganged up and threw stones and spears . At first, his music charmed them as well, but eventually their numbers and clamor overwhelmed his music and he was hit by the spears. Both myths then state that his lyre

12705-511: The surface of Vega by a team of astronomers at the Observatoire du Pic du Midi . This is the first such detection of a magnetic field on a spectral class A star that is not an Ap chemically peculiar star . The average line of sight component of this field has a strength of −0.6 ± 0.3 gauss (G) . This is comparable to the mean magnetic field on the Sun. Magnetic fields of roughly 30 G have been reported for Vega, compared to about 1 G for

12826-399: The third found to exhibit such an effect in the timeframe, and unable to be completely explained by known phenomena. The light curve observed over the next 100 days was consistent with that of a supernova or even a hypernova , dubbed SN 2005nc . The host galaxy proved elusive to find at first, although it was subsequently identified. In orbit around the orange subgiant star HD 177830

12947-514: The three-letter abbreviation "Lyr" for the constellation in 1922. German cartographer Johann Bayer used the Greek letters alpha through nu to label the most prominent stars in the constellation. English astronomer John Flamsteed observed and labelled two stars each as delta , epsilon , zeta and nu. He added pi and rho , not using xi and omicron as Bayer used these letters to denote Cygnus and Hercules on his map. The brightest star in

13068-502: The time, including Struve, credited Bessel with the first published parallax result. However, Struve's initial result was actually close to the currently accepted value of 0.129″, as determined by the Hipparcos astrometry satellite. The brightness of a star, as seen from Earth, is measured with a standardized, logarithmic scale . This apparent magnitude is a numerical value that decreases in value with increasing brightness of

13189-411: The traditional classes, with features of Beta Lyrae, W Ursae Majoris , and cataclysmic variables . It may be a representative of a very brief phase in which the system is transitioning into a contact binary . It can be found less than a degree away from the naked-eye star 16 Lyrae , a 5th-magnitude A-type subgiant located around 37 parsecs distant. The brightest star not included in the asterism and

13310-435: The very end, Orpheus faltered and looked back, causing Eurydice to be left in the Underworld forever. Orpheus spent the rest of his life strumming his lyre while wandering aimlessly through the land, rejecting all marriage offers from women. There are two main competing myths relating to the death of Orpheus. According to Eratosthenes , Orpheus failed to make a necessary sacrifice to Dionysus due to his regard for Apollo as

13431-451: The westernmost cataloged by Bayer or Flamsteed is Kappa Lyrae , a typical red giant around 73 parsecs distant. Similar bright orange or red giants include the 4th-magnitude Theta Lyrae , Lambda Lyrae , and HD 173780 . Lambda is located just south of Gamma, Theta is positioned in the east, and HD 173780, the brightest star in the constellation with no Bayer or Flamsteed designation, is more southernly. Just north of Theta and of almost exactly

13552-523: The year to observers north of latitude 42°S. Its main asterism consists of six stars, and 73 stars in total are brighter than magnitude 6.5. The constellation's boundaries, as set by Belgian astronomer Eugène Delporte in 1930, are defined by a 17-sided polygon. In the equatorial coordinate system , the right ascension coordinates of these borders lie between 18 14 and 19 28 , while the declination coordinates are between +25.66° and +47.71°. The International Astronomical Union (IAU) adopted

13673-605: Was based upon the hour at which Vega set below the horizon. In Chinese , 織女 ( Zhī Nǚ ), meaning Weaving Girl (asterism) , refers to an asterism consisting of Vega, ε Lyrae and ζ Lyrae . Consequently, the Chinese name for Vega is 織女一 ( Zhī Nǚ yī , English: the First Star of Weaving Girl ). In Chinese mythology , there is a love story of Qixi ( 七夕 ) in which Niulang ( 牛郎 , Altair ) and his two children ( β Aquilae and γ Aquilae ) are separated from their mother Zhinü ( 織女 , lit. "weaver girl", Vega) who

13794-407: Was estimated at 11″ ± 2″ , or 70– 100 AU . The disk of dust is produced as radiation pressure from Vega pushes debris from collisions of larger objects outward. However, continuous production of the amount of dust observed over the course of Vega's lifetime would require an enormous starting mass—estimated as hundreds of times the mass of Jupiter . Hence it is more likely to have been produced as

13915-525: Was hypothesized as either a perturbation of the dust disk by a planet or else an orbiting object that was surrounded by dust. However, images by the Keck telescope had ruled out a companion down to magnitude 16, which would correspond to a body with more than 12 times the mass of Jupiter. Astronomers at the Joint Astronomy Centre in Hawaii and at UCLA suggested that the image may indicate

14036-548: Was known as Urcuchillay by the Incas and was worshipped as an animal deity. Lyra is bordered by Vulpecula to the south, Hercules to the west, Draco to the north, and Cygnus to the east. Covering 286.5 square degrees , it ranks 52nd of the 88 modern constellations in size. It appears prominently in the northern sky during the Northern Hemisphere's summer, and the whole constellation is visible for at least part of

14157-569: Was one of the hottest known exoplanets, in orbit around the F-type main-sequence star WASP-3 . Similar to TrES-1b, irregularities in the transits had left open the possibility of a second planet, although this now appears unlikely as well. Lyra is one of three constellations (along with neighboring Cygnus and Draco) to be in the Kepler Mission 's field of view, and as such it contains many more known exoplanets than most constellations. One of

14278-495: Was placed in the sky by Zeus and Orpheus's bones were buried by the muses . In a third myth, he was killed by the Thracian women because he looked on the rites of Father Liber (Dionysus). The Roman book De astronomia , attributed to Hyginus , also records another myth about Lyra, which said that it belonged to Theseus "for he was skilful in all the arts and seems to have learned the lyre as well". The book reports that

14399-805: Was seen by the Arabs as a vulture or an eagle diving with folded wings. In Wales , Lyra is known as King Arthur's Harp ( Talyn Arthur ), and King David's harp. The Persian Hafiz called it the Lyre of Zurah. It has been called the Manger of the Infant Saviour, Praesepe Salvatoris. In Australian Aboriginal astronomy , Lyra is known by the Boorong people in Victoria as the Malleefowl constellation. Lyra

14520-416: Was the pole star in the year 12,000 BCE, and will again become the pole star around 14,000 CE. Vega is one of the most magnificent of all stars, and has been called "arguably the next most important star in the sky after the Sun ". Vega was the first star other than the Sun to be photographed , as well as the first to have a clear spectrum recorded, showing absorption lines for the first time. The star

14641-455: Was the first single main-sequence star other than the Sun to be known to emit X-rays , and is surrounded by a circumstellar debris disk , similar to the Kuiper Belt . Vega forms one corner of the famous Summer Triangle asterism; along with Altair and Deneb , these three stars form a prominent triangle during the northern hemisphere summer. Vega also forms one vertex of a much smaller triangle, along with Epsilon and Zeta Lyrae . Zeta forms

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