Astronomy:HD 194612

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Short description: Star in the constellation Octans
HD 194612
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Octans
Right ascension  20h 38m 18.6064s[1]
Declination −81° 17′ 20.6261″[1]
Apparent magnitude (V) 5.89±0.01[2]
Characteristics
Evolutionary stage RGB[3]
Spectral type K5 III[4]
U−B color index +2.02[5]
B−V color index +1.71[5]
Astrometry
Radial velocity (Rv)0.3±0.4[6] km/s
Proper motion (μ) RA: +1.597[1] mas/yr
Dec.: −37.819[1] mas/yr
Parallax (π)4.3006 ± 0.0707[1] mas
Distance760 ± 10 ly
(233 ± 4 pc)
Absolute magnitude (MV)−0.56[7]
Details
Mass2.1[8] M
Radius59.9[9] R
Luminosity598±13[10] L
Surface gravity (log g)0.99±0.02[3] cgs
Temperature3941±122[9] K
Rotational velocity (v sin i)2.3±1.2[11] km/s
Other designations
CPD−81°906, GC 28578, HD 194612, HIP 101843, HR 7812, SAO 258864[12]
Database references
SIMBADdata

HD 194612 (HR 7812) is a solitary[13] orange hued star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.9,[2] making it visible to the naked eye under ideal conditions. Parallax measurements place it at a distance of 760 light years[1] and it has a low heliocentric radial velocity of 0.3 km/s.[6]

This is a red giant with a stellar classification of K5 III,[4] and Gaia DR3 stellar evolution models place it on the red giant branch.[3] It has double the mass of the Sun[8] and an enlarged radius of 59.9 R[9] due to its evolved status. It shines with a luminosity of 598 solar luminosity[10] from its photosphere at an effective temperature of 3,941 K.[9] Like many giants, HD 194612 has a comparatively modest projected rotational velocity, which is around 2.3 km/s.[11]

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 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  4. 4.0 4.1 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°. Bibcode1975mcts.book.....H. 
  5. 5.0 5.1 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. 
  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. Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331–346. doi:10.1134/S1063773712050015. ISSN 1063-7737. Bibcode2012AstL...38..331A. 
  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 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. ISSN 0004-6256. Bibcode2019AJ....158..138S. 
  10. 10.0 10.1 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.
  11. 11.0 11.1 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. 
  12. "HR 7812". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HR+7812. 
  13. 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. 
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