Gamma Tauri

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γ Tauri
Taurus constellation map.svg
Red circle.svg
Location of γ Tauri (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Taurus
Right ascension 04h 19m 47.6037s [1]
Declination +15° 37′ 39.512″ [1]
Apparent magnitude  (V)3.654 [2]
Characteristics
Spectral type G8III [3]
U−B color index +0.84 [4]
B−V color index +0.99 [4]
Astrometry
Radial velocity (Rv)38.7 ± 0.9 [5]  km/s
Proper motion (μ)RA: +115.29 [1]   mas/yr
Dec.: -23.86 [1]   mas/yr
Parallax (π)21.17 ± 1.17  mas [1]
Distance 154 ± 9  ly
(47 ± 3  pc)
Absolute magnitude  (MV)0.22 [3]
Details
Mass 2.70 ± 0.13 [6]   M☉
Radius 13.4 ± 0.2 [7]   R☉
Luminosity 85 [3]   L☉
Surface gravity (log g)2.58-2.61 [7]   cgs
Temperature 4,844 ± 47 [7]   K
Metallicity [Fe/H]+0.11 [8]   dex
Rotation 253 days [9]
Rotational velocity (v sin i)4 [10]  km/s
Age 430–530 [3] [6]   Myr
Other designations
Prima Hyadum, Hyadum I, [11] 54 Tauri, BD+15°612, FK5 159, HD 27371, HIP 20205, HR 1346, SAO 93868, GC 5226, WDS 04198+1538 [2]
Database references
SIMBAD data

Gamma Tauri (γ Tauri, abbreviated Gamma Tau, γ Tau) is either a solitary, binary or double star (the Washington Double Star Catalog notes it as a "Dubious Double" or "Bogus Binary" [12] ) that marks the tip of the "V" in the constellation of Taurus. It is a member of, and located within about 2.5 parsecs of the center of, the Hyades star cluster, the nearest open cluster to the Sun. Based upon parallax measurements, Gamma Tauri is approximately 154 light-years from the Sun.

Contents

Considered as a pair of stars, the two components are designated Gamma Tauri A (officially named Prima Hyadum /ˌpraɪməˈhaɪədəm/ , the traditional name for the system) [13] and B.

Nomenclature

γ Tauri (Latinised to Gamma Tauri) is the system's Bayer designation. The designations of the two potential components as Gamma Tauri A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU). [14]

Gamma Tauri bore the traditional name Hyadum I, [11] which is Latin for "First of the Hyades". In 2016, the IAU organized a Working Group on Star Names (WGSN) [15] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems. [16] It approved the name Prima Hyadum for the component Gamma Tauri A on 5 September 2017 and it is now so included in the List of IAU-approved Star Names. [13]

In Chinese, 畢宿 (Bì Xiù), meaning Net , refers to an asterism consisting of Gamma Tauri, Epsilon Tauri, Delta³ Tauri, Delta¹ Tauri, Alpha Tauri (Aldebaran), 71 Tauri and Lambda Tauri. [17] Consequently, the Chinese name for γ Tauri itself is 畢宿四 (Bì Xiù sì), "the Fourth Star of Net". [18]

Properties

Gamma Tauri presents as a spectral class G8 or K0 [2] [3] giant star with an apparent magnitude of +3.65. This star has passed through the main sequence phase is now a red clump giant, meaning it is using nuclear fusion of helium at its core to provide energy. [19] Age estimates for Gamma Tauri range from 430 million [3] to 530 million years. [6] By comparison, the age of the Hyades cluster is about 625 million years with an error margin of 50 million years. [6]

The angular diameter of this star has been measured using the CHARA array to 2% accuracy. After correcting for limb darkening, this gives the stellar radius as 13.4 times the radius of the Sun. [7] The star is radiating about 85 times the luminosity of the Sun [3] and has 2.7 times the Sun's mass. [6] With its large size and low projected rotational velocity of 4 km s−1, [10] it takes about 253 days to complete a rotation. [9]

Related Research Articles

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<span class="mw-page-title-main">Bellatrix</span> Star in the constellation Orion

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<span class="mw-page-title-main">Meissa</span> Star in the constellation Orion

Meissa, designated Lambda Orionis is a star in the constellation of Orion. It is a multiple star approximately 1,300 ly away with a combined apparent magnitude of 3.33. The main components are an O8 giant star and a B-class main sequence star, separated by about 4″. Despite Meissa being more luminous and only slightly further away than Rigel, it appears 3 magnitudes dimmer at visual wavelengths, with much of its radiation emitted in the ultraviolet due to its high temperature.

<span class="mw-page-title-main">Gamma Pegasi</span> Variable B-type star in the constellation Pegasus

Gamma Pegasi is a star in the constellation of Pegasus, located at the southeast corner of the asterism known as the Great Square. It has the formal name Algenib ; the Bayer designation Gamma Pegasi is Latinized from γ Pegasi and abbreviated Gamma Peg or γ Peg. The average apparent visual magnitude of +2.84 makes this the fourth-brightest star in the constellation. The distance to this star has been measured using the parallax technique, yielding a value of roughly 470 light-years.

<span class="mw-page-title-main">Gamma Leonis</span> Star in the constellation Leo

Gamma Leonis, also named Algieba, is a binary star system in the constellation of Leo. In 2009, a planetary companion around the primary was announced.

<span class="mw-page-title-main">Gamma Arietis</span> Star in the constellation Aries

Gamma Arietis is a binary star in the northern constellation of Aries. The two components are designated γ1 Arietis or Gamma Arietis B and γ2 Arietis or Gamma Arietis A. γ1 Arietis may itself be a spectroscopic binary with a low mass companion.

21 Tauri, formally known as Asterope, is a component of the Asterope double star in the Pleiades open cluster. 21 Tauri is the stars' Flamsteed designation. This star is potentially faintly visible to the naked eye with an apparent visual magnitude of 5.76 in ideal conditions, although anybody viewing the object is likely to instead see the pair as a single elongated form of magnitude 5.6. The distance to 21 Tauri can be estimated from its annual parallax shift of 7.6 mas, yielding a range of around 431 light years. It is moving further from the Earth with a heliocentric radial velocity of +6 km/s.

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Gamma Cancri, or γ Cancri, is a star in the northern constellation of Cancer. It is formally named Asellus Borealis, the traditional name of the system. Based on parallax measurements, it is located at a distance of approximately 181 light years from the Sun. The star is drifting further away with a radial velocity of 29 km/s. In 1910 this star was reported to be a spectroscopic binary by O. J. Lee, but is now considered a single star. Since it is near the ecliptic, it can be occulted by the Moon and, very rarely, by planets.

<span class="mw-page-title-main">Gamma Capricorni</span> Star in the constellation Capricornus

Gamma Capricorni or γ Capricorni, formally named Nashira, is a giant star in the constellation of Capricornus. Based on parallax measurements obtained during the Hipparcos mission, it is located at a distance of approximately 157 light-years from the Sun. The star is drifting closer with a radial velocity of −31 km/s. It is 2.56 degrees south of the ecliptic, so it can be occulted by the Moon, and (rarely) by planets.

<span class="mw-page-title-main">Epsilon Ophiuchi</span> Star in the constellation Ophiuchus

Epsilon Ophiuchi or ε Ophiuchi, formally named Yed Posterior, is a red giant star in the constellation of Ophiuchus. Located less than five degrees south of the celestial equator in the eastern part of the constellation, it forms a naked eye optical double with Delta Ophiuchi. With an apparent visual magnitude of 3.220, the star can be seen with the naked eye from most of the Earth under suitably dark skies. Parallax measurements yield an estimated distance of 106.4 light-years from the Sun.

<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">Merope (star)</span> B-type subgiant star in the constellation Taurus

Merope, designated 23 Tauri, is a star in the constellation of Taurus and a member of the Pleiades star cluster. It is approximately 440 light-years (135 pc) away.

Pi Tauri is a solitary, yellow-hued star in the zodiac constellation of Taurus. With an apparent visual magnitude of +4.69, it is bright enough to be visible to the naked eye. Although it appears to lie among the stars of the Hyades cluster, it is not itself a member, being three times farther from Earth than the cluster. The distance to this star, as determined using an annual parallax shift of 7.83 mas as seen from the Earth, is around 420 light years. At that range, the visual magnitude of the star is diminished by an extinction factor of 0.24 due to interstellar dust.

<span class="mw-page-title-main">Gamma Lyrae</span> Star in the constellation Lyra

Gamma Lyrae, Latinised from γ Lyrae, and formally named Sulafat, is the second-brightest star in the northern constellation of Lyra. With an apparent visual magnitude of 3.3, it is readily visible to the naked eye. Parallax measurements yield an estimated distance of 620 light-years from the Sun. At that distance, the visual magnitude of the star is diminished by an extinction factor of 0.12±0.03 due to interstellar dust.

Delta<sup>1</sup> Tauri Binary star in the constellation Taurus

Delta¹ Tauri is a double star in the zodiac constellation of Taurus. Based upon an annual parallax shift of 20.96 mas as seen from Earth, it is located roughly 156 light-years distant from the Sun. The system is faintly visible to the naked eye with a combined apparent visual magnitude of +3.772. It is considered a member of the Hyades cluster.

<span class="mw-page-title-main">G Scorpii</span> Star in the constellation Scorpius

G Scorpii, also named Fuyue, is a giant star in the constellation of Scorpius. It has an apparent magnitude of +3.19. It is approximately 126 light-years from the Sun.

Delta<sup>2</sup> Tauri Star in the constellation Taurus

Delta2 Tauri is a solitary, white-hued star in the zodiac constellation of Taurus. Based upon an annual parallax shift of 20.21 mas as seen from Earth, it is located roughly 161 light years distant from the Sun. It is separated from δ1 Tauri by 0.3° on the sky and is faintly visible to the naked eye with an apparent visual magnitude of +4.80. The star is considered a member of the Hyades cluster.

<span class="mw-page-title-main">Gamma Canis Majoris</span> Star in the constellation Canis Major

Gamma Canis Majoris, also named Muliphein, is a star in the constellation of Canis Major. It is unclear exactly why this relatively faint star was given the 'gamma' designation, but possibly because it is in the same part of the constellation as Sirius (alpha) and Mirzam (beta).

<span class="mw-page-title-main">Gamma Librae</span> Star in the constellation Libra

Gamma Librae is a suspected binary star system in the constellation of Libra. It is visible to the naked eye, having an apparent visual magnitude of +3.91. Based upon an annual parallax shift of 19.99 mas as seen from Earth, it lies 163 light years from the Sun.

<span class="mw-page-title-main">Gamma Gruis</span> Star in the constellation Grus

Gamma Gruis or γ Gruis, formally named Aldhanab, is a star in the southern constellation of Grus. With an apparent visual magnitude of 3.0, it is the third-brightest star in Grus. Based upon parallax measurements, this star is located at a distance of roughly 211 light-years from the Sun.

References

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  2. 1 2 3 "NSV 1553 - Variable Star". SIMBAD. Centre de Données astronomiques de Strasbourg . Retrieved 2009-09-22.
  3. 1 2 3 4 5 6 7 Takeda, Yoichi; Sato, Bun'ei; Murata, Daisuke (August 2008). "Stellar Parameters and Elemental Abundances of Late-G Giants". Publications of the Astronomical Society of Japan. 60 (4): 781–802. arXiv: 0805.2434 . Bibcode:2008PASJ...60..781T. doi:10.1093/pasj/60.4.781. S2CID   16258166.
  4. 1 2 Johnson, H. L.; Morgan, W. W. (1953). "Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas". Astrophysical Journal. 117: 313–352. Bibcode:1953ApJ...117..313J. doi:10.1086/145697.
  5. ↑ Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union. Bibcode:1967IAUS...30...57E.
  6. 1 2 3 4 5 da Silva, L.; et al. (November 2006). "Basic physical parameters of a selected sample of evolved stars". Astronomy and Astrophysics. 458 (2): 609–623. arXiv: astro-ph/0608160 . Bibcode:2006A&A...458..609D. doi:10.1051/0004-6361:20065105. S2CID   9341088.
  7. 1 2 3 4 Boyajian, Tabetha S.; et al. (February 2009). "Angular Diameters of the Hyades Giants Measured with the CHARA Array". The Astrophysical Journal. 691 (2): 1243–1247. arXiv: 0810.2238 . Bibcode:2009ApJ...691.1243B. doi:10.1088/0004-637X/691/2/1243. S2CID   17092177.
  8. ↑ Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. (March 2008). "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants". Astronomy and Astrophysics. 480 (1): 91–101. arXiv: 0712.1370 . Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788. S2CID   16602121.
  9. 1 2 Setiawan, J.; et al. (July 2004), "Precise radial velocity measurements of G and K giants. Multiple systems and variability trend along the Red Giant Branch", Astronomy and Astrophysics, 421: 241–254, Bibcode:2004A&A...421..241S, doi: 10.1051/0004-6361:20041042-1
  10. 1 2 Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1): 1. Bibcode:1970CoAsi.239....1B.
  11. 1 2 Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York, NY: Dover Publications Inc. p.  390. ISBN   0-486-21079-0.
  12. ↑ "Washington Double Star Catalog". United States Naval Observatory. Archived from the original on 14 February 2011. Retrieved 2 January 2018.
  13. 1 2 "Naming Stars". IAU.org. Retrieved 16 December 2017.
  14. ↑ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv: 1012.0707 [astro-ph.SR].
  15. ↑ "IAU Working Group on Star Names (WGSN)" . Retrieved 22 May 2016.
  16. ↑ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  17. ↑ (in Chinese)中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN   978-986-7332-25-7.
  18. ↑ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 Archived 2008-10-25 at the Wayback Machine , Hong Kong Space Museum. Accessed on line November 23, 2010.
  19. ↑ de Bruijne, J. H. J.; Hoogerwerf, R.; de Zeeuw, P. T. (February 2001). "A Hipparcos study of the Hyades open cluster. Improved colour-absolute magnitude and Hertzsprung-Russell diagrams". Astronomy and Astrophysics . 367 (1): 111–147. arXiv: astro-ph/0011565 . Bibcode:2001A&A...367..111D. doi:10.1051/0004-6361:20000410. S2CID   55224801.
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