AA Tauri

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AA Tauri
AATauLightCurve.png
A visual band light curve for AA Tauri, adapted from Bouvier et al. (2013). [1] The main plot shows the long term variation, and the inset plot shows the periodic variation after the dramatic dimming in 2011.
Observation data
Epoch J2000.0        Equinox J2000.0
Constellation Taurus
Right ascension 04h 34m 55.42019s [2]
Declination +24° 28′ 53.0336″ [2]
Apparent magnitude  (V)12.2 to 16.1 [3]
Characteristics
Spectral type K7Ve [4]
Variable type T Tauri-type? [4]
Astrometry
Radial velocity (Rv)16.98±0.04 [5]  km/s
Proper motion (μ)RA: +5.323  mas/yr [2]
Dec.: −20.680  mas/yr [2]
Parallax (π)7.4255 ± 0.0868  mas [2]
Distance 439 ± 5  ly
(135 ± 2  pc)
Details
Mass 0.76 [6]   M☉
Radius 1.81 [6]   R☉
Luminosity 0.8 [6]   L☉
Temperature 4,060 [6]   K
Rotational velocity (v sin i)12.8±1.1 [5]  km/s
Age 2.4 [6]   Myr
Other designations
AA Tau, GCRV 55202, XEST 25-026, AN 196.1930, GSC 01833-00851, 2MASS J04345542+2428531, CSI+24-04319, MHA 259-17, 2E 0431.8+2422, IRAS 04318+2422, UBV 4396, 2E 1098, IRAS F04318+2422, XEST 25-OM-003 [7]
Database references
SIMBAD data

AA Tauri is a young variable star in the equatorial constellation of Taurus, located in the Taurus-Auriga star-forming region. It is too faint to view with the naked eye, having an apparent visual magnitude that varies from 12.2 down to 16.1. [3] The star is located approximately 439 light-years (135 parsecs ) away from the Sun based on parallax, and is drifting further away with a radial velocity of +17 km/s. [5]

Contents

The stellar classification for this object is K7Ve, [4] matching a K-type main-sequence star that displays emission features. It is an eruptive variable of the T Tauri type [3] with an estimated age of 2.4 million years. The object has 76% of the mass of the Sun, 181% of the Sun's radius, [6] and is spinning with a projected rotational velocity of 13 km/s. [5] AA Tauri is radiating 80% of the luminosity of the Sun at an effective temperature of 4,060 K. [6]

Variability

AA Tauri shows brightness variations of one to two magnitudes over an 8.2-day period. The brightness has been described as "roughly constant, interrupted by quasi-cyclic fading episodes". [8] The periodic variations are ascribed to eclipses of the star by a warped dust disk around it. [9]

In 2011, AA Tauri faded by about two magnitudes and has remained at the fainter level since then. The star also became significantly more reddened. The eight-day variations continue, with a maximum brightness now around magnitude 14 and magnitude 16.5 at its faintest. It is theorised that the root cause of this dimness is a warp in the accretion disk, located at a distance of 7.7 AU or more from the centre, that was brought into the line of sight by its elliptical motion around the central star. [1]

Search for planets

In their 2003 paper, Bouvier et al. invoked the possible presence of a substellar object to explain peculiar and periodic eclipses occurring to the young star every 8.3 days, though they considered it unlikely that such a companion could be responsible for said variability. [8] They inferred a mass of 20 times that of Jupiter for the perturbing object and an orbital separation of 0.08 Astronomical Units. Later studies find no evidence for a planet, instead finding multiple rings with accretion streams between them. [9]

Related Research Articles

<span class="mw-page-title-main">Theta Tauri</span> Binary star in the constellation Taurus

Theta Tauri is a wide double star in the constellation of Taurus and a member of the Hyades open cluster.

<span class="mw-page-title-main">Omicron Tauri</span> Star in the constellation Taurus

ο Tauri, Latinized as Omicron Tauri, is a binary star system in the constellation Taurus, near the constellation border with Cetus. It has a yellow hue and is visible to the naked eye with an apparent visual magnitude of 3.61. It is approximately 191 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −20 km/s. As the westernmost bright point of light in Taurus, this system has the Flamsteed designation 1 Tauri; Omicron Tauri is the Bayer designation.

<span class="mw-page-title-main">Nu Tauri</span> Star in the constellation Taurus

ν Tauri, Latinized as Nu Tauri, is a single star in the zodiac constellation of Taurus. It is a white-hued star and is visible to the naked eye with an apparent visual magnitude of +3.91. This object is located 117 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −6 km/s. It is predicted to come to within roughly 18.4 ly of the Sun in around five million years.

<span class="mw-page-title-main">CT Chamaeleontis</span> Star in the constellation Chamaleon

CT Chamaeleontis (CT Cha) is a T Tauri star - a primary of the star system in the constellation of Chamaeleon. It has an apparent visual magnitude which varies between 12.31 and 12.43. The star is still accreting material at rate 6×10−10 M☉/year.

<span class="mw-page-title-main">XZ Tauri</span> Star in the constellation Taurus

XZ Tauri is a binary system approximately 460 light-years away in the constellation Taurus. The system consists of two T Tauri stars orbiting each other about 6 billion kilometers apart. The system made news in 2000 when a superflare was observed in the system.

<span class="mw-page-title-main">Taurus molecular cloud</span> Interstellar molecular cloud in the constellations Taurus and Auriga

The Taurus molecular cloud (TMC-1) is an interstellar molecular cloud in the constellations Taurus and Auriga. This cloud hosts a stellar nursery containing hundreds of newly formed stars. The Taurus molecular cloud is only 140 pc away from Earth, making it possibly the nearest large star formation region. It has been important in star formation studies at all wavelengths.

90 Tauri is a star in the zodiac constellation of Taurus, located 144 light-years away from the Sun. It is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of 4.27. 90 Tauri is a member of the Hyades cluster and is listed as a double star.

<span class="mw-page-title-main">LkCa 15</span> Star system in the constellation Taurus

LkCa 15 is a T Tauri star in the Taurus Molecular Cloud. These types of stars are relatively young pre-main-sequence stars that show irregular variations in brightness. It has a mass that is about 97% of the Sun, an effective temperature of 4370 K, and is slightly cooler than the Sun. Its apparent magnitude is 11.91, meaning it is not visible to the naked eye.

<span class="mw-page-title-main">GG Tauri</span> Star in the constellation Taurus

GG Tauri, often abbreviated as GG Tau, is a quintuple star system in the constellation Taurus. At a distance of about 450 light years away, it is located within the Taurus-Auriga Star Forming Region. The system comprises three stars orbiting each other in a hierarchical triple system, known as GG Tauri A, and another binary star system more distant from the central system, known as GG Tauri B.

<span class="mw-page-title-main">FU Tauri</span> Brown dwarf binary star system in the constellation Taurus

FU Tauri is a brown dwarf binary system in the constellation of Taurus about 429 light years away. The secondary is very close to the lower limit for brown dwarfs and several databases list it as a distant massive exoplanet.

<span class="mw-page-title-main">RW Aurigae</span> Young binary star system in the constellation Auriga

RW Aurigae is a young binary system in the constellation of Auriga about 530 light years away, belonging to the Taurus-Auriga association of the Taurus Molecular Cloud. RW Aurigae B was discovered in 1944.

<span class="mw-page-title-main">RY Tauri</span> Star in the constellation Taurus

RY Tauri is a young T Tauri star in the constellation of Taurus about 450 light years away, belonging to the Taurus Molecular Cloud. It is more massive than typical T Tauri stars, and may be an intermediate between this class and the Herbig Ae/Be star type.

<span class="mw-page-title-main">BP Tauri</span> Star in the constellation Taurus

BP Tauri is a young T Tauri star in the constellation of Taurus about 416 light years away, belonging to the Taurus Molecular Cloud.

<span class="mw-page-title-main">HK Tauri</span> Young binary star system in the constellation of Taurus

HK Tauri is a young binary star system in the constellation of Taurus about 434 light-years away, belonging to the Taurus Molecular Cloud.

<span class="mw-page-title-main">GI Tauri and GK Tauri</span> Binary star system in the constellation of Taurus

GK Tauri is a young T Tauri-type pre-main sequence star in the constellation of Taurus about 421 light years away, belonging to the Taurus Molecular Cloud.

<span class="mw-page-title-main">GV Tauri</span> Young binary star system in the constellation of Taurus

GK Tauri is a young binary system composed of T Tauri-type pre-main sequence stars in the constellation of Taurus about 466 light years away, belonging to the Taurus Molecular Cloud.

<span class="mw-page-title-main">DL Tauri</span> Protostar system with planetary system in the constellation of Taurus

DL Tauri is a young T Tauri-type pre-main sequence stars in the constellation of Taurus about 522 light years away, belonging to the Taurus Molecular Cloud. It is partially obscured by the foreground gas cloud rich in carbon monoxide, and is still accreting mass, producing 0.14 L☉ due to release of accretion energy. The stellar spectrum shows the lines of ionized oxygen, nitrogen, sulfur and iron.

<span class="mw-page-title-main">EX Lupi</span>

EX Lupi is a young, single T-Tauri star in the southern constellation of Lupus. An irregular variable, it is the prototype of young, low-mass eruptive stars named EXors, with EX Lupi being this object's variable star designation. At its minimal activity level, EX Lupi resembles a classical T-Tauri star of the M0 dwarf type. The low latitude of this star, at a declination of −40°, makes it difficult for northern observers to view. Based on parallax measurements, it is located at a distance of about 505 light years from the Sun. The star lies next to a gap in the Lupus cloud complex, a star forming region.

<span class="mw-page-title-main">CQ Tauri</span> Star in the constellation Taurus

CQ Tauri is a young variable star in the equatorial constellation of Taurus. It is too faint to be visible to the naked eye with an apparent visual magnitude that ranges from 8.7 to 12.25. The distance to this star is approximately 487 light years based on parallax measurements, and it is drifting further away with a radial velocity of ~23 km/s. It appears to be part of the T-association Tau 4. CQ Tauri lies close enough to the ecliptic to undergo lunar occultations.

<span class="mw-page-title-main">72 Tauri</span> Star in the constellation of Taurus

72 Tauri is a possible binary star in the zodiac constellation of Taurus. It is faintly visible to the naked eye with an apparent visual magnitude of +5.5, although only 0.29° from the brighter υ Tauri. Based upon an annual parallax shift of 7.9 mas seen from Earth, it is around 410 light years from the Sun.

References

  1. 1 2 Bouvier, J.; Grankin, K.; Ellerbroek, L. E.; Bouy, H.; Barrado, D. (2013). "AA Tauri's sudden and long-lasting deepening: Enhanced extinction by its circumstellar disk". Astronomy & Astrophysics. 557: A77. arXiv: 1304.1487 . Bibcode:2013A&A...557A..77B. doi:10.1051/0004-6361/201321389. S2CID   216079418.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 1 2 3 Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID   125853869.
  4. 1 2 3 Herbig, G. H. (1977). "Radial velocities and spectral types of T Tauri stars". Astrophysical Journal. 214: 747–758. Bibcode:1977ApJ...214..747H. doi: 10.1086/155304 .
  5. 1 2 3 4 Nguyen, Duy Cuong; et al. (February 2012). "Close Companions to Young Stars. I. A Large Spectroscopic Survey in Chamaeleon I and Taurus-Auriga". The Astrophysical Journal. 745 (2): 25. arXiv: 1112.0002 . Bibcode:2012ApJ...745..119N. doi:10.1088/0004-637X/745/2/119. S2CID   119265730. 119.
  6. 1 2 3 4 5 6 7 Güdel; et al. (2007). "The XMM-Newton Extended Survey of the Taurus Molecular Cloud (XEST)". Astronomy and Astrophysics . 468 (2): 353–377. arXiv: astro-ph/0609160 . Bibcode:2007A&A...468..353G. doi:10.1051/0004-6361:20065724. S2CID   8846597.
  7. ↑ "AA Tau". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-08-10.
  8. 1 2 Bouvier; et al. (2003). "Eclipses by circumstellar material in the T Tauri star AA Tau. II. Evidence for non-stationary magnetospheric accretion". Astronomy and Astrophysics . 409: 169–192. arXiv: astro-ph/0306551 . Bibcode:2003A&A...409..169B. doi:10.1051/0004-6361:20030938. S2CID   15140780.
  9. 1 2 Loomis, Ryan A.; Öberg, Karin I.; Andrews, Sean M.; MacGregor, Meredith A. (2017). "A Multi-ringed, Modestly Inclined Protoplanetary Disk around AA Tau". The Astrophysical Journal. 840 (1): 23. arXiv: 1704.02006 . Bibcode:2017ApJ...840...23L. doi: 10.3847/1538-4357/aa6c63 . S2CID   119370612.
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