Astronomy:HD 6

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Short description: Star in the constellation Pisces
HD 6
Observation data
Equinox J2000.0]] (ICRS)
Constellation Pisces
Right ascension  00h 05m 03.82339s[1]
Declination −00° 30′ 10.9306″[1]
Apparent magnitude (V) 6.30±0.01[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type K0 III[4]
U−B color index +1.03[5]
B−V color index +1.11[5]
Astrometry
Radial velocity (Rv)15.3±0.7[6] km/s
Proper motion (μ) RA: +45.245[1] mas/yr
Dec.: −53.594[1] mas/yr
Parallax (π)6.9277 ± 0.0368[1] mas
Distance471 ± 3 ly
(144.3 ± 0.8 pc)
Absolute magnitude (MV)0.62[7]
Details
Mass1.95[8] M
Radius12.4[9] R
Luminosity72.4[10] L
Surface gravity (log g)1.8[3] cgs
Temperature4,807±75[9] K
Metallicity [Fe/H]−0.03[3] dex
Rotational velocity (v sin i)2.8±0.8[11] km/s
Age1.62[8] Gyr
Other designations
BD−01°4525, GC 51, HD 6, HIP 417, HR 2, SAO 128569[12]
Database references
SIMBADdata

HD 6 is a star in the equatorial constellation of Pisces, and is located a couple of degrees southeast of the intersection between the ecliptic and the celestial equator. It is a yellow-hued star that is just barely visible to the naked eye with an apparent visual magnitude of 6.3.[2] The star is located at a distance of 471 light years from the Sun based on parallax,[1] and is drifting further away with a radial velocity of 15.3 km/s.[6] It has an absolute magnitude of 0.62.[7]

An evolved red giant with a stellar classification K0 III,[4] the star has moved off the main sequence by cooling and expanding. At the age of 1.6 billion years,[8] is now a red clump giant on the horizontal branch that is engaged in core helium fusion.[3] It has nearly double the mass of the Sun[8] and has expanded to 12.4[9] times the Sun's radius. The star is radiating 72 times the luminosity of the Sun[10] from its photosphere at an effective temperature of 4,807 K.[9]

References

  1. 1.0 1.1 1.2 1.3 1.4 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.
  2. 2.0 2.1 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode2000A&A...355L..27H. 
  3. 3.0 3.1 3.2 3.3 Tautvaišienė, G. et al. (March 2013), "Red clump stars of the Milky Way - laboratories of extra-mixing", Monthly Notices of the Royal Astronomical Society 430 (1): 621–627, doi:10.1093/mnras/sts663, Bibcode2013MNRAS.430..621T. 
  4. 4.0 4.1 Houk, N.; Swift, C. (1999), "Michigan catalogue of two-dimensional spectral types for the HD Stars", Michigan Spectral Survey 5, Bibcode1999MSS...C05....0H. 
  5. 5.0 5.1 Cousins, A. W. J. (1971). "Photometric standard stars". Royal Observatory Annals 7. Bibcode1971ROAn....7.....C. 
  6. 6.0 6.1 Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. ISSN 1063-7737. Bibcode2006AstL...32..759G. 
  7. 7.0 7.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  8. 8.0 8.1 8.2 8.3 Demarque, Pierre; Woo, Jong‐Hak; Kim, Yong‐Cheol; Yi, Sukyoung K. (December 2004). "Y 2 Isochrones with an Improved Core Overshoot Treatment". The Astrophysical Journal Supplement Series 155 (2): 667–674. doi:10.1086/424966. ISSN 0067-0049. Bibcode2004ApJS..155..667D. 
  9. 9.0 9.1 9.2 9.3 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode2019AJ....158..138S. 
  10. 10.0 10.1 Luck, R. Earle (25 August 2015). "Abundances in the Local Region. I. G and K Giants". The Astronomical Journal 150 (3): 88. doi:10.1088/0004-6256/150/3/88. ISSN 0004-6256. Bibcode2015AJ....150...88L. 
  11. Fekel, Francis C.; Watson, Lyndon C. (November 1998). "A Search for Lithium-rich Giants among Stars with Infrared Excesses". The Astronomical Journal 116 (5): 2466–2474. doi:10.1086/300614. ISSN 0004-6256. Bibcode1998AJ....116.2466F. 
  12. "HD 6". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+6. 

External links

Coordinates: Sky map 00h 05m 03.80s, −00° 30′ 11.0″