20 Arietis

20 Arietis is a single[8] star in the northern constellation of Aries. 20 Arietis is the Flamsteed designation. It has an apparent visual magnitude of 5.79, which is bright enough to be just faintly visible to the naked eye as a yellow-white hued star. The star is located approximately 137 light years away from the Sun based upon parallax. It has a relatively high proper motion, traversing the celestial sphere at the rate of 0.188 arc seconds per annum.[9] 20 Arietis is receding from the Earth with a heliocentric radial velocity of +25 km/s.[2]

20 Arietis
Observation data
Epoch J2000      Equinox J2000
Constellation Aries
Right ascension 02h 15m 46.04981s[1]
Declination +25° 46′ 58.5741″[1]
Apparent magnitude (V) 5.79[2]
Characteristics
Spectral type F6 III-IV[3] or F6 IV-V[4]
B−V color index 0.439±0.005[2]
Astrometry
Radial velocity (Rv)+25.1±0.3[2] km/s
Proper motion (μ) RA: +177.067[1] mas/yr
Dec.: −64.694[1] mas/yr
Parallax (π)24.1949 ± 0.1121[1] mas
Distance134.8 ± 0.6 ly
(41.3 ± 0.2 pc)
Absolute magnitude (MV)2.67[2]
Details
Mass1.49±0.10[5] M☉
Radius1.94±0.24[5] R☉
Luminosity6.6±0.3[6] L☉
Surface gravity (log g)4.03±0.05[5] cgs
Temperature6,416±60[5] K
Metallicity [Fe/H]0.27±0.05[5] dex
Rotational velocity (v sin i)8.0[6] km/s
Age2.19+0.44
−0.37[5] Gyr
Other designations
20 Ari, BD+25°373, GC 2707, HD 13871, HIP 10540, HR 656, SAO 75239[7]
Database references
SIMBADdata

Gray et al. (2001) gave the stellar classification of 20 Arietis as F6 III-IV,[3] matching an F-type star with spectral traits intermediate between a giant and a subgiant star. Harlan (1969) had found a less-evolved class of F6 IV-V.[4] The star is around two billion years old[5] with an estimated 1.5 times the mass of the Sun[5] and two times the Sun's radius.[5] It is spinning with a projected rotational velocity of 8.0 km/s[6] and has a higher than solar metallicity.[5] The star is radiating 6.6[6] times the luminosity of the Sun from its photosphere at an effective temperature of around 6,416 K.[5]

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. Gray, R. O.; et al. (2001), "The Physical Basis of Luminosity Classification in the Late A-, F-, and Early G-Type Stars. I. Precise Spectral Types for 372 Stars", The Astronomical Journal, 121 (4): 2148, Bibcode:2001AJ....121.2148G.
  4. Harlan, E. A. (September 1969), "MK classifications for F- and G-type stars. I", Astronomical Journal, 74: 916–919, Bibcode:1969AJ.....74..916H, doi:10.1086/110881.
  5. Yee, Samuel W.; et al. (February 2017), "Precision Stellar Characterization of FGKM Stars using an Empirical Spectral Library", The Astrophysical Journal, 836 (1): 17, arXiv:1701.00922, Bibcode:2017ApJ...836...77Y, doi:10.3847/1538-4357/836/1/77, 77.
  6. Brewer, John M.; Fischer, Debra A.; Valenti, Jeff A.; Piskunov, Nikolai (2016), "Spectral Properties of Cool Stars: Extended Abundance Analysis of 1,617 Planet-search Stars", The Astrophysical Journal Supplement Series, 225 (2): 32, arXiv:1606.07929, Bibcode:2016ApJS..225...32B, doi:10.3847/0067-0049/225/2/32.
  7. "20 Ari". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 17 August 2017.
  8. 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  9. Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal, 129 (3): 1483–1522, arXiv:astro-ph/0412070, Bibcode:2005AJ....129.1483L, doi:10.1086/427854.
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