HD 4628

HD 4628 (96 G. Piscium) is a main sequence star in the equatorial constellation of Pisces. It has a spectral classification of K2.5 V and an effective temperature of 5,055 K, giving it an orange-red hue with a slightly smaller mass and girth than our Sun. HD 4628 lies at a distance of approximately 24.3 light years from the Sun.[1] The apparent magnitude is just sufficient for this star to be viewed with the unaided eye. The star appears to be slightly older than our Sun—approximately 5.4 billion years old.[9] The surface activity is low and, based upon the detection of UV emission, it may have a relatively cool corona with a temperature of one million K.[12]

HD 4628
Observation data
Epoch J2000      Equinox J2000
Constellation Pisces
Right ascension 00h 48m 22.98s[1]
Declination +05° 16′ 50.2″[1]
Apparent magnitude (V) 5.74[2]
Characteristics
Spectral type K2.5 V[3]
U−B color index +0.60[3]
B−V color index +0.89[3]
Astrometry
Radial velocity (Rv)−10.8[4] km/s
Proper motion (μ) RA: 757.11±0.48[1] mas/yr
Dec.: −1141.33±0.34[1] mas/yr
Parallax (π)134.14 ± 0.51[1] mas
Distance24.31 ± 0.09 ly
(7.45 ± 0.03 pc)
Absolute magnitude (MV)6.37[5]
Details
Mass0.70±0.10[6] M☉
Radius0.749±0.051[7] R☉
Luminosity0.28[6] L☉
Surface gravity (log g)4.39±0.16[6] cgs
Temperature5055±40[6] K
Metallicity [Fe/H]–0.22[8] dex
Rotation38.0 days[8]
Age5.4[9] Gyr
Other designations
96 G. Piscium,[10] BD +04°123, GCTP 156.00, Gl 33, HD 4628, HIP 3765, HR 222, Lal 1299, LHS 121, LTT 10285, SAO 109471, Wolf 25.[11]
Database references
SIMBADdata

The star has a relatively high proper motion of 1.4″ per year and is moving in our general direction with a radial velocity of −10.8[4] km/s. HD 4628 will make its closest approach to the Sun in about 32,000 years, when it comes within 20 ly (7.3 pc).[13] No definitive companion has yet been found in orbit around this star. In 1958 it was thought to have stellar companion that was also a flare star, but this was subsequently disproved.[14]

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. Archived from the original on 2016-04-02. Vizier catalog entry
  2. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M.
  3. Gray, R. O.; et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal, 132 (1): 161–170, arXiv:astro-ph/0603770, Bibcode:2006AJ....132..161G, doi:10.1086/504637
  4. Nordström, B.; et al. (May 2014), "The Geneva-Copenhagen survey of the Solar neighbourhood. Ages, metallicities, and kinematic properties of ~14000 F and G dwarfs", Astronomy and Astrophysics, 418: 989–1019, arXiv:astro-ph/0405198, Bibcode:2004A&A...418..989N, doi:10.1051/0004-6361:20035959.
  5. Holmberg, J.; et al. (July 2009), "The Geneva-Copenhagen survey of the solar neighbourhood. III. Improved distances, ages, and kinematics", Astronomy and Astrophysics, 501 (3): 941–947, arXiv:0811.3982, Bibcode:2009A&A...501..941H, doi:10.1051/0004-6361/200811191.
  6. Ghezzi, L.; et al. (September 2010), "Stellar Parameters and Metallicities of Stars Hosting Jovian and Neptunian Mass Planets: A Possible Dependence of Planetary Mass on Metallicity", The Astrophysical Journal, 720 (2): 1290–1302, arXiv:1007.2681, Bibcode:2010ApJ...720.1290G, doi:10.1088/0004-637X/720/2/1290
  7. van Belle, Gerard T.; von Braun, Kaspar (2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2): 1085–1098. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637X/694/2/1085.
  8. Maldonado, J.; et al. (October 2010), "A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups", Astronomy and Astrophysics, 521: A12, arXiv:1007.1132, Bibcode:2010A&A...521A..12M, doi:10.1051/0004-6361/201014948
  9. Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008), "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics", The Astrophysical Journal, 687 (2): 1264–1293, arXiv:0807.1686, Bibcode:2008ApJ...687.1264M, doi:10.1086/591785
  10. Gould, B. A., Uranometria Argentina, Reprinted and updated by Pilcher, F, archived from the original on 2012-02-27, retrieved 2010-07-16
  11. "HD 4628 -- High proper-motion Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-07-15.
  12. Mathioudakis, M.; et al. (November 1994), "Detection of EUV emission from the low activity dwarf HD 4628: Evidence for a cool corona", Astronomy and Astrophysics, 291 (2): 517–520, Bibcode:1994A&A...291..517M.
  13. Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics, 575: 13, arXiv:1412.3648, Bibcode:2015A&A...575A..35B, doi:10.1051/0004-6361/201425221, A35.
  14. Hartkopf, W. I.; McAlister, H. A. (January 1984), "Binary stars unresolved by speckle interferometry. III", Publications of the Astronomical Society of the Pacific, 96: 105–116, Bibcode:1984PASP...96..105H, doi:10.1086/131309.


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