Astronomy:79 Tauri

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Short description: Star in the constellation Taurus
79 Tauri
Taurus constellation map.svg
Red circle.svg
Location of 79 Tauri (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Taurus
Right ascension  04h 28m 50.1636s[1]
Declination +13° 02′ 51.367″[1]
Apparent magnitude (V) 5.014[2]
Characteristics
Spectral type kA5hF0VmF0[3]
U−B color index +0.12[4]
B−V color index +0.23[4]
Astrometry
Radial velocity (Rv)+33.7276±0.0324[5] km/s
Proper motion (μ) RA: +104.066[1] mas/yr
Dec.: −14.900[1] mas/yr
Parallax (π)20.7158 ± 0.0899[1] mas
Distance157.4 ± 0.7 ly
(48.3 ± 0.2 pc)
Absolute magnitude (MV)1.58[6]
Details
Mass1.9[1] M
Radius2.4[1] R
Luminosity18[1] L
Surface gravity (log g)3.88[1] cgs
Temperature7,681[1] K
Metallicity [Fe/H]+0.35[6] dex
Rotation0.925 d[7]
Rotational velocity (v sin i)106.3[7] km/s
Age971[1] Myr
Other designations
Database references
SIMBADdata

79 Tauri, also known as b Tauri, is an Am star in the constellation of Taurus with an apparent magnitude of 5.0. It is a member of the Hyades open cluster and parallax measurements by Gaia give a distance of about 157 light years.

The spectrum of 79 Tauri shows abnormal abundances of metals, with many showing unusually strong absorption lines, but some such as calcium showing weaker lines than expected. This is represented in the spectral type kA5hF0VmF0, which is F0 based on its hydrogen lines, but A5 based on its calcium K-lines, and F0 based on the lines of other metals.[3] Other publications often give the spectral class based on hydrogen lines as A7.[8] It is classified as an Am star, a type of star with strong magnetic fields and slow rotation causing stratification of elements within its atmosphere.[9]

79 Tauri lies about two degrees south of the main V asterism of the Hyades open cluster. It lies 11 light years from the centre of the cluster and is generally considered to be a member.[10] With a mass of 1.9 M, it is a main sequence star with an age of 971 million years. It has an effective temperature of 7,681 K and a radius of 2.4 R, it radiates 18 times the luminosity of the Sun.

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. Joner, Michael D.; Taylor, Benjamin J.; Laney, C. David; Van Wyk, Francois (2006). "Homogeneous Photometry for the Hyades: Scale-Factor and Zero-Point Tests of Previously Published BV(RI)C Photometry". The Astronomical Journal 132 (1): 111. doi:10.1086/504410. Bibcode2006AJ....132..111J. 
  3. 3.0 3.1 Islik, S. (1968). "Chemical composition and physical structure of 7 early-type stars". Memorie della Societa Astronomica Italiana 39: 19. Bibcode1968MmSAI..39...19I. 
  4. 4.0 4.1 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1. 
  5. Leão, I. C.; Pasquini, L.; Ludwig, H. -G.; De Medeiros, J. R. (2019). "Spectroscopic and astrometric radial velocities: Hyades as a benchmark". Monthly Notices of the Royal Astronomical Society 483 (4): 5026. doi:10.1093/mnras/sty3215. Bibcode2019MNRAS.483.5026L. 
  6. 6.0 6.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode2012AstL...38..331A. 
  7. 7.0 7.1 van Saders, Jennifer L.; Pinsonneault, Marc H. (October 2013). "Fast Star, Slow Star; Old Star, Young Star: Subgiant Rotation as a Population and Stellar Physics Diagnostic". The Astrophysical Journal 776 (2): 20. doi:10.1088/0004-637X/776/2/67. 67. Bibcode2013ApJ...776...67V. 
  8. Skiff, B. A. (2014). "VizieR Online Data Catalog: Catalogue of Stellar Spectral Classifications (Skiff, 2009-2016)". VizieR On-line Data Catalog: B/Mk. Originally Published in: Lowell Observatory (October 2014) 1. Bibcode2014yCat....1.2023S. 
  9. Renson, P.; Manfroid, J. (May 2009). "Catalogue of Ap, HgMn and Am stars". Astronomy and Astrophysics 498 (3): 961–966. doi:10.1051/0004-6361/200810788. Bibcode2009A&A...498..961R. 
  10. Lodieu, N.; Smart, R. L.; Pérez-Garrido, A.; Silvotti, R. (2019). "A 3D view of the Hyades stellar and sub-stellar population". Astronomy and Astrophysics 623: A35. doi:10.1051/0004-6361/201834045. Bibcode2019A&A...623A..35L.