Rho Piscium

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Rho Piscium
Pisces IAU.svg
Red circle.svg
Location of ρ Piscium (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pisces
Right ascension 01h 26m 15.26209s[1]
Declination +19° 10′ 20.4526″[1]
Apparent magnitude (V) +5.344[2]
Spectral type F2 V[3]
B−V color index +0.374[2]
Radial velocity (Rv)−7.7±1.0[4] km/s
Proper motion (μ) RA: −26.89[1] mas/yr
Dec.: +11.12[1] mas/yr
Parallax (π)39.66 ± 0.25[1] mas
Distance82.2 ± 0.5 ly
(25.2 ± 0.2 pc)
Absolute magnitude (MV)+3.34[5]
Mass1.31[6] M
Radius1.1[7] R
Luminosity3.6[8] L
Surface gravity (log g)4.41±0.14[6] cgs
Temperature6,822±232[6] K
Metallicity [Fe/H]−0.31[9] dex
Rotational velocity (v sin i)60.1[10] km/s
Age778[6] Myr
Other designations
ρ Psc, 93 Piscium, BD+18° 187, HD 8723, HIP 6706, HR 413, SAO 92436[11]
Database references

Rho Piscium (ρ Piscium) is a solitary,[12] yellow-hued star in the zodiac constellation of Pisces. With an apparent visual magnitude of +5.34,[2] it is faintly visible to the naked eye. Based upon an annual parallax shift of 39.66 mas as seen from Earth,[1] it is located 82 light years from the Sun. It is a member of the thin disk population of the Milky Way.[9]

This is an F-type main sequence star with a stellar classification of F2 V.[3] It is a suspected variable star that ranges in magnitude from a maximum of 5.35 to a minimum of 5.44 magnitude.[13] The star is a source of X-ray emission with a luminosity of 117.6×1020 W.[14] It is 778[6] million years old and is spinning with a projected rotational velocity of 60.1 km/s.[10] The star has 1.3[6] times the mass of the Sun and about 1.1[7] times the Sun's radius. It is radiating 3.6[8] times the Sun's luminosity from its photosphere at an effective temperature of 6,822 K.[6]


In Chinese, 右更 (Yòu Gèng), meaning Official in Charge of the Pasturing, refers to an asterism consisting of refers to an asterism consisting of ρ Piscium, η Piscium, π Piscium, ο Piscium and 104 Piscium. Consequently, ρ Piscium itself is known as 右更一 (Yòu Gèng yī, English: the First Star of Official in Charge of the Pasturing.)[15]


  1. ^ a b c d e f 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.
  2. ^ a b c Høg, E.; et al. (March 2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H, doi:10.1888/0333750888/2862.
  3. ^ a b Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Northern Sample I", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637.
  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, A61.
  5. ^ 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.
  6. ^ a b c d e f g 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.
  7. ^ a b Pasinetti Fracassini, L. E.; et al. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy & Astrophysics (3rd ed.), 367: 521–24, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  8. ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  9. ^ a b Ibukiyama, A.; Arimoto, N. (November 2002), "HIPPARCOS age-metallicity relation of the solar neighbourhood disc stars", Astronomy and Astrophysics, 394: 927–941, arXiv:astro-ph/0207108, Bibcode:2002A&A...394..927I, doi:10.1051/0004-6361:20021157.
  10. ^ a b Schröder, C.; et al. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377.
  11. ^ "rho Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-25.
  12. ^ Eggleton, P. P.; Tokovinin, A. A. (September 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.
  13. ^ Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085.
  14. ^ Huensch, M.; et al. (October 1998), "The ROSAT all-sky survey catalogue of optically bright main-sequence stars and subgiant stars", Astronomy and Astrophysics Supplement, 132: 155–171, Bibcode:1998A&AS..132..155H, doi:10.1051/aas:1998287.
  15. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日