Delta Piscium

Delta Piscium (δ Piscium) is a solitary,[7] orange-hued star in the zodiac constellation of Pisces. It has an apparent visual magnitude of +4.4,[2] so it is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 10.5 mas, it is around 311 light-years (95 parsecs) from the Sun.[6] The visual magnitude of the star is diminished by an interstellar absorption factor of 0.08 due to interstellar dust.[8]

Delta Piscium
Location of δ Piscium (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Pisces
Right ascension 00h 48m 40.94433s[1]
Declination +07° 35′ 06.2926″[1]
Apparent magnitude (V) +4.416[2]
Characteristics
Spectral type K4 IIIb[3]
U−B color index +1.831[2]
B−V color index +1.500[2]
Astrometry
Radial velocity (Rv)+32.45±0.18[4] km/s
Proper motion (μ) RA: +83.10[1] mas/yr
Dec.: −49.58[1] mas/yr
Parallax (π)10.48 ± 0.22[1] mas
Distance311 ± 7 ly
(95 ± 2 pc)
Absolute magnitude (MV)−0.46[5]
Details[4]
Mass1.65[3] M☉
Radius44 R☉
Luminosity447 L☉
Surface gravity (log g)1.0 cgs
Temperature3,963±4 K
Metallicity [Fe/H]−0.20 dex
Rotational velocity (v sin i)5.5 km/s
Age2.98[3] Myr
Other designations
δ Psc, 63 Piscium, BD+06° 107, FK5 28, HD 4656, HIP 3786, HR 224, SAO 109474, WDS J00487+0735A[6]
Database references
SIMBADdata

This is an evolved K-type giant star with a stellar classification of K4 IIIb.[3] It has around 1.65 times the mass of the Sun and, at the age of three billion years,[3] has expanded to 44[4] times the Sun's radius. The star is radiating 447 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,963 K.[4]

Because Delta Piscium is positioned near the ecliptic, so it is subject to lunar occultations.[9] It has a magnitude 13.99 visual companion at an angular separation of 135.0 arc seconds on a position angle of 12°, as of 2011.[10]

Naming

In Chinese, 外屏 (Wài Píng), meaning Outer Fence, refers to an asterism of stars, δ Piscium, ε Piscium, ζ Piscium, μ Piscium, ν Piscium, ξ Piscium and α Piscium. Consequently, the Chinese name for δ Piscium itself is 外屏一 (Wài Píng yī, English: the First Star of Outer Fence.)[11]

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. Cousins, A. W. J. (1984), "Standardisation of broad band photometry of equatorial standards", South Africa Astronomical Observatory Circular, 8: 59–67, Bibcode:1984SAAOC...8...59C.
  3. Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
  4. Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209.
  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, S2CID 119257644.
  6. "del Psc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-07-31.
  7. 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, S2CID 14878976.
  8. Famaey, B.; et al. (2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430: 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304.
  9. 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.
  10. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22
  11. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 19 日
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