Astronomy:HD 92845

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Short description: Star in the constellation Antlia
HD 92845
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Antlia
Right ascension  10h 42m 43.1844s[1]
Declination −32° 42′ 56.413″[1]
Apparent magnitude (V) 5.62±0.01[2]
Evolutionary stage subgiant[3]
Spectral type A0 V[4]
B−V color index +0.00[5]
Radial velocity (Rv)4.5±0.5[6] km/s
Proper motion (μ) RA: −28.903[1] mas/yr
Dec.: +1.262[1] mas/yr
Parallax (π)4.1113 ± 0.2655[1] mas
Distance790 ± 50 ly
(240 ± 20 pc)
Absolute magnitude (MV)−0.67[7]
Mass3.1±0.1[3] M
Radius5.31[8] R
Luminosity206+72−53[3] L
Surface gravity (log g)3.5[9] cgs
Temperature9,376±109[8] K
Metallicity [Fe/H]0.00[10] dex
Rotational velocity (v sin i)81±3[11] km/s
Age282±34[12] Myr
Other designations
CD−32°7572, CPD−32°2953, FK5 1277, GC 14732, HIP 52407, HR 4194, SAO 201665, WDS J10427-3243A[13]
Database references

HD 92845 (HR 4194) is a probable astrometric binary[14] in the southern constellation Antlia. It has an apparent magnitude of 5.62, allowing it to be faintly seen with the naked eye. Parallax measurements place the system at a distance of 790 light years and it is currently receding with a heliocentric radial velocity of 4.5 km/s.

HD 92845 has a stellar classification of A0 V,[4] indicating that it is an ordinary A-type main-sequence star. However, stellar evolution models from Zorec and Royer reveal it to be a subgiant that has just left the main sequence.[3] It has 3.1 times the mass of the Sun[3] but has expanded to an enlarged radius of 5.31 R.[8] It radiates with a luminosity 206 times greater than the Sun[3] from its photosphere at an effective temperature of 9,376 K,[8] giving a white hue. At an age of 282 million years,[12] HD 92845 spins quickly with a projected rotational velocity of 81 km/s.[11]

There is an optical companion 17 away along a position angle of 214° as of 1999.[15]


  1. 1.0 1.1 1.2 1.3 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. 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 3.4 3.5 Zorec, J.; Royer, F. (1 January 2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. ISSN 0004-6361. Bibcode2012A&A...537A.120Z. 
  4. 4.0 4.1 Cucchiaro, A.; Macau-Hercot, D.; Jaschek, M.; Jaschek, C. (July 1978). "Spectral classification from the ultraviolet line features of S2/68 spectra. III. Early A-type stars.". Astronomy and Astrophysics Supplement Series 33: 15–26. ISSN 0365-0138. Bibcode1978A&AS...33...15C. 
  5. 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. 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. (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 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. 
  9. 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. 
  10. Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters 38 (12): 771–782. doi:10.1134/S1063773712120031. ISSN 0320-0108. Bibcode2012AstL...38..771G. 
  11. 11.0 11.1 Royer, F.; Gerbaldi, M.; Faraggiana, R.; Gómez, A. E. (January 2002). "Rotational velocities of A-type stars". Astronomy & Astrophysics 381 (1): 105–121. doi:10.1051/0004-6361:20011422. ISSN 0004-6361. Bibcode2002A&A...381..105R. 
  12. 12.0 12.1 Gerbaldi, M.; Faraggiana, R.; Burnage, R.; Delmas, F.; Gómez, A. E.; Grenier, S. (June 1999). "Search for reference A0 dwarf stars: Masses and luminosities revisited withHipparcos parallaxes". Astronomy and Astrophysics Supplement Series 137 (2): 273–292. doi:10.1051/aas:1999248. ISSN 0365-0138. Bibcode1999A&AS..137..273G. 
  13. "HR 4194". SIMBAD. Centre de données astronomiques de Strasbourg. 
  14. 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. 
  15. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal 122 (6): 3466–3471. doi:10.1086/323920. ISSN 0004-6256. Bibcode2001AJ....122.3466M. 
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