Phi1 Hydrae

Phi¹ Hydrae, Latinized from φ¹ Hydrae, is a yellow-hued star in the constellation Hydra. Its apparent magnitude is 7.61,^[2] making it too faint to be seen with the naked eye. Based upon an annual parallax shift of 12.3 mas as seen from Earth,^[1] it is located about 266 light years from the Sun. It forms a triangle with the brighter φ² Hydrae and φ³ Hydrae, between μ Hydrae and ν Hydrae.

For other stars with this Bayer designation, see φ Hydrae

Phi¹ Hydrae

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Hydra
Right ascension	10h 32m 41.16026s[1]
Declination	−16° 57′ 31.4110″[1]
Apparent magnitude (V)	7.61[2]
Characteristics
Spectral type	G2 V[3]
Astrometry
Radial velocity (Rv)	+15.8±0.3[4] km/s
Proper motion (μ)	RA: −20.964[5] mas/yr Dec.: −87.082[5] mas/yr
Parallax (π)	12.2814 ± 0.0688 mas[5]
Distance	266 ± 1 ly (81.4 ± 0.5 pc)
Absolute magnitude (MV)	+3.30[6]
Details[7]
Mass	1.34 M☉
Radius	2.1[5] R☉
Luminosity	4.4[6] L☉
Surface gravity (log g)	3.90±0.08 cgs
Temperature	5,992±50 K
Metallicity [Fe/H]	+0.15±0.05 dex
Age	4.1 Gyr
Other designations
φ1 Hya, 43 Hydrae, BD−16° 3078, HD 91369, HIP 51614, SAO 156047[8]
Database references
SIMBAD	data

Phi¹ Hydrae is an ordinary G-type main-sequence star, having a Sun-like stellar classification of G2 V and a photospheric temperature only slightly higher than the sun.^[3] However, the mass is 34%^[7] greater than the Sun, and it is radiating 4.4 times the Sun's luminosity.^[6] Phi¹ Hydrae is moving further from the Sun with a radial velocity of +15.8 km/s.^[4]

References

1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
2. Høg, E.; et al. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27, Bibcode:2000A&A...355L..27H.
3. Houk, N.; Smith-Moore, M. (1988), "Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars", Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, 4, Ann Arbor, MI, USA: Department of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
5. 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.
6. 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, S2CID 119257644.
7. Bensby, T.; et al. (2014), "Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the solar neighbourhood", Astronomy & Astrophysics, 562 (A71): 28, arXiv:1309.2631, Bibcode:2014A&A...562A..71B, doi:10.1051/0004-6361/201322631, S2CID 118786105.
8. "43 Hya". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-01-09.