Astronomy:HD 4628

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Short description: Star in the constellation Pisces
HD 4628
Observation data
Equinox J2000.0]] (ICRS)
Constellation Pisces
Right ascension  00h 48m 22.97634s[1]
Declination +05° 16′ 50.2096″[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)−10.41±0.15[1] km/s
Proper motion (μ) RA: 755.561[1] mas/yr
Dec.: −1,141.745[1] mas/yr
Parallax (π)134.4948 ± 0.0578[4] mas
Distance24.25 ± 0.01 ly
(7.435 ± 0.003 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
Temperature5,055±40[6] K
Metallicity [Fe/H]–0.22[8] dex
Rotation38.0 days[8]
Age5.4[9] Gyr
Other designations
BD+04°123, HD 4628, HIP 3765, HR 222, SAO 109471, LHS 121, LTT 10285, Wolf 25, Lal 1299[10]
Database references
SIMBADdata

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 the Sun. HD 4628 lies at a distance of approximately 24.3 light years from the Sun based on parallax.[1] The apparent magnitude of 5.7[2] is just sufficient for this star to be viewed with the unaided eye. The star appears to be slightly older than the Sun—approximately 5.4 billion years in age.[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.[11]

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 −10.4 km/s.[1] HD 4628 will make its closest approach to the Sun in about 32,000 years, when it comes within 20 ly (7.3 pc).[12] 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.[13]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  2. 2.0 2.1 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode1986EgUBV........0M. 
  3. 3.0 3.1 3.2 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, doi:10.1086/504637, Bibcode2006AJ....132..161G 
  4. Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode2021A&A...649A...1G.  Gaia EDR3 record for this source at VizieR.
  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, doi:10.1051/0004-6361/200811191, Bibcode2009A&A...501..941H. 
  6. 6.0 6.1 6.2 6.3 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, doi:10.1088/0004-637X/720/2/1290, Bibcode2010ApJ...720.1290G 
  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. doi:10.1088/0004-637X/694/2/1085. Bibcode2009ApJ...694.1085V. 
  8. 8.0 8.1 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, doi:10.1051/0004-6361/201014948, Bibcode2010A&A...521A..12M 
  9. 9.0 9.1 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, doi:10.1086/591785, Bibcode2008ApJ...687.1264M 
  10. "HD 4628 -- High proper-motion Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+4628, retrieved 2016-07-15. 
  11. 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, Bibcode1994A&A...291..517M. 
  12. Bailer-Jones, C. A. L. (March 2015), "Close encounters of the stellar kind", Astronomy & Astrophysics 575: 13, doi:10.1051/0004-6361/201425221, A35, Bibcode2015A&A...575A..35B. 
  13. 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, doi:10.1086/131309, Bibcode1984PASP...96..105H. 
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