Astronomy:Upsilon Octantis

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Short description: Star in the constellation of Octans
υ Octantis
Octans IAU.svg
Red circle.svg
Location of υ Octantis (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Octans
Right ascension  22h 31m 37.5152s[1]
Declination −85° 58′ 02.1104″[1]
Apparent magnitude (V) 5.75±0.01[2]
Characteristics
Spectral type K0 III[3]
U−B color index +0.88[4]
B−V color index +1.02[4]
Astrometry
Radial velocity (Rv)19±7.8[5] km/s
Proper motion (μ) RA: −37.556[1] mas/yr
Dec.: +61.431[1] mas/yr
Parallax (π)9.5042 ± 0.0351[1] mas
Distance343 ± 1 ly
(105.2 ± 0.4 pc)
Absolute magnitude (MV)+0.77[6]
Details[7]
Mass2.12±0.07 M
Radius10.3±0.2 R
Luminosity56±1.1 L
Surface gravity (log g)2.7±0.1 cgs
Temperature4,910±42 K
Metallicity [Fe/H]0.00±0.03 dex
Rotational velocity (v sin i)1.5±1.3[8] km/s
Other designations
υ Oct, CPD−86°406, FK5 1670, GC 31327, HD 211539, HIP 111196, HR 8505, SAO 258932[9]
Database references
SIMBADdata

Upsilon Octantis (Upsilon Oct), Latinized from υ Octantis, is a solitary star[10] in the southern circumpolar constellation Octans. It is faintly visible to the naked eye with an apparent magnitude of 5.75[2] and is located 343 light years away from the Solar System.[1] However, it is receding with a heliocentric radial velocity of 19 km/s.[5]

Upsilon Oct has a stellar classification of K0 III,[3] indicating that it is a red giant. At present it has 2.12 times the mass of the Sun but has expanded to 10.3 times its girth.[7] It shines with a luminosity of 56 solar luminosity from its enlarged photosphere at an effective temperature of 4,910 K,[7] giving a yellowish orange hue when viewed at night. Upsilon Oct has a solar metallicity, with an iron abundance equivalent to the Sun's.[7] It spins leisurely with a poorly-constrained projected rotational velocity of 1.5 km/s.[8]

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 Kharchenko, N.V.; Scholz, R.-D.; Piskunov, A.E.; Röser, S.; Schilbach, E. (November 2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten 328 (9): 889–896. doi:10.1002/asna.200710776. ISSN 0004-6337. Bibcode2007AN....328..889K. 
  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 7.3 Ottoni, G.; Udry, S.; Ségransan, D.; Buldgen, G.; Lovis, C.; Eggenberger, P.; Pezzotti, C.; Adibekyan, V. et al. (January 2022). "CORALIE radial-velocity search for companions around evolved stars (CASCADES): I. Sample definition and first results: Three new planets orbiting giant stars". Astronomy & Astrophysics 657: A87. doi:10.1051/0004-6361/202040078. ISSN 0004-6361. Bibcode2022A&A...657A..87O. 
  8. 8.0 8.1 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. 
  9. "ups Oct". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ups+Oct. 
  10. 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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