Astronomy:HD 222806

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Short description: Suspected binary in the constellation Octans
HD 222806
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Octans
Right ascension  23h 44m 40.8646s[1]
Declination −78° 47′ 29.1861″[1]
Apparent magnitude (V) 5.74±0.01[2]
Characteristics
Spectral type K1 III[3]
U−B color index +1.06[4]
B−V color index +1.11[4]
Astrometry
Radial velocity (Rv)21.3±0.8[5] km/s
Proper motion (μ) RA: +49.327[1] mas/yr
Dec.: +7.345[1] mas/yr
Parallax (π)5.7766 ± 0.0592[1] mas
Distance565 ± 6 ly
(173 ± 2 pc)
Absolute magnitude (MV)−0.11[6]
Details
Mass1.26[7] M
Radius18.77[8] R
Luminosity151±2[9] L
Surface gravity (log g)1.95[7] cgs
Temperature4,865±122[10] K
Metallicity [Fe/H]+0.37[11] dex
Rotational velocity (v sin i)<1[12] km/s
Other designations
CPD−79°1239, FK5 3906, GC 32960, HD 222806, HIP 117125, HR 8995, SAO 258179[13][14]
Database references
SIMBADdata

HD 222806 (HR 8995) is a suspected astrometric binary[15] in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.74,[2] allowing it to be faintly seen with the naked eye. Parallax measurements place the system at a distance of 565 light years[1] and it is currently receding with a heliocentric radial velocity of 21 km/s.[5]

The visible component has a stellar classification of K1 III,[3] indicating that it is a red giant. At present it has 126% the mass of the Sun,[7] but has expanded to almost 19 times its girth.[8] It radiates at 151 times the luminosity of the Sun[9] from its enlarged photosphere at an effective temperature of 4,865 K,[10] giving it an orange hue. HD 222806 is metal enriched with an iron abundance over twice that of the Sun and is believed to be a member of the young disk population.[11] It spins with a projected rotational velocity lower than km/s.[12]

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 Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations -90_ to -53_ƒ0.. Bibcode1975mcts.book.....H. 
  4. 4.0 4.1 Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory 4: 99–110. Bibcode1966CoLPL...4...99J. 
  5. 5.0 5.1 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. 
  6. Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation" (in en). Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode2012AstL...38..331A. 
  7. 7.0 7.1 7.2 Anders, F. et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics 628: A94. doi:10.1051/0004-6361/201935765. ISSN 0004-6361. Bibcode2019A&A...628A..94A. 
  8. 8.0 8.1 Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (2022). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics 657: A7. doi:10.1051/0004-6361/202142146. ISSN 0004-6361. Bibcode2022A&A...657A...7K. 
  9. 9.0 9.1 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.
  10. 10.0 10.1 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. ISSN 0004-6256. Bibcode2019AJ....158..138S. 
  11. 11.0 11.1 Eggen, O. J. (February 1994). "Evolved GK stars near the Sun. 2: The young disk population". The Astronomical Journal 107: 594. doi:10.1086/116879. ISSN 0004-6256. Bibcode1994AJ....107..594E. 
  12. 12.0 12.1 De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars: V. Southern stars⋆⋆⋆". Astronomy & Astrophysics 561: A126. doi:10.1051/0004-6361/201220762. ISSN 0004-6361. Bibcode2014A&A...561A.126D. 
  13. "HD 222806". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+222806. 
  14. Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino 1. Bibcode1879RNAO....1.....G. 
  15. Eggleton, P. P.; Tokovinin, A. A. (11 September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society 389 (2): 869–879. doi:10.1111/j.1365-2966.2008.13596.x. ISSN 0035-8711. Bibcode2008MNRAS.389..869E.