18 Tauri

18 Tauri is a single[9] star in the zodiac constellation of Taurus, located 444 light years away from the Sun. It is visible to the naked eye as a faint, blue-white hued star with an apparent visual magnitude of 5.66.[2] The star is moving further from the Earth with a heliocentric radial velocity of +4.8.[5] It is a member of the Pleiades[10] open cluster, which is positioned near the ecliptic and thus is subject to lunar occultations.[11]

18 Tauri
Observation data
Epoch J2000      Equinox J2000
Constellation Taurus
Right ascension  03h 45m 09.73954s[1]
Declination +24° 50′ 21.3495″[1]
Apparent magnitude (V) 5.66[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type B8 V[4]
B−V color index −0.064±0.012[2]
Astrometry
Radial velocity (Rv)+4.8±0.8[5] km/s
Proper motion (μ) RA: +20.744[1] mas/yr
Dec.: −46.538[1] mas/yr
Parallax (π)7.3405 ± 0.1237[1] mas
Distance444 ± 7 ly
(136 ± 2 pc)
Absolute magnitude (MV)0.19[2]
Details
Mass3.34±0.06[3] M☉
Radius2.89[6] R☉
Luminosity160+18
−15[3] L☉
Surface gravity (log g)4.126±0.113[7] cgs
Temperature13,748±223[7] K
Rotational velocity (v sin i)212[3] km/s
Other designations
18 Tau, BD+24°546, GC 4485, HD 23324, HIP 17527, HR 1144, SAO 76137[8]
Database references
SIMBADdata

This is a B-type main-sequence star with a stellar classification of B8 V,[4] and is about halfway through its main sequence lifetime.[3] It displays an infrared excess, suggesting the presence of an orbiting debris disk with a black body temperature of 75 K at a separation of 137.8 AU from the host star.[6] The star has 3.34[3] times the mass of the Sun and 2.89[6] times the Sun's radius. It is radiating 160[3] times the Sun's luminosity from its photosphere at an effective temperature of 13,748 K.[7] 18 Tauri has a high rate of spin, showing a projected rotational velocity of 212 km/s.[3]

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015.
  3. Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691.
  4. Morgan, W. W.; Keenan, P. C. (1973), "Spectral Classification", Annual Review of Astronomy and Astrophysics, 11: 29, Bibcode:1973ARA&A..11...29M, doi:10.1146/annurev.aa.11.090173.000333.
  5. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065.
  6. Cotten, Tara H.; Song, Inseok (July 2016), "A Comprehensive Census of Nearby Infrared Excess Stars", The Astrophysical Journal Supplement Series, 225 (1): 24, arXiv:1606.01134, Bibcode:2016ApJS..225...15C, doi:10.3847/0067-0049/225/1/15, 15.
  7. David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146.
  8. "18 Tau". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-03-20.
  9. Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x
  10. Eggen, Olin J. (October 1998), "The Pleiades and alpha Persei Clusters", The Astronomical Journal, 116 (4): 1810–1815, Bibcode:1998AJ....116.1810E, doi:10.1086/300533
  11. Meyer, C.; et al. (1995), "Observations of lunar occultations at Observatoire de la Cote d'Azur", Astronomy and Astrophysics Supplement, 110: 107, Bibcode:1995A&AS..110..107M. See SAO 76137 on p. 112
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