Astronomy:HD 85945

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Short description: Giant star in the constellation Ursa Major

Coordinates: Sky map 09h 57m 13.61s, +57° 25′ 05.54″

HD 85945
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ursa Major[1]
Right ascension  09h 57m 13.61s[2]
Declination +57° 25′ 05.54″[2]
Apparent magnitude (V) 5.959±0.009[2]
Characteristics
Evolutionary stage Horizontal branch[3]
Spectral type G6III:Fe-0.5[2]
Apparent magnitude (B) 6.854±0.015[2]
Apparent magnitude (G) 5.733[2]
Apparent magnitude (J) 4.513±0.028[2]
Apparent magnitude (H) 4.141±0.036[2]
Apparent magnitude (K) 3.978±0.3[2]
B−V color index 0.895[4]
Astrometry
Radial velocity (Rv)−46.55±0.12[5] km/s
Proper motion (μ) RA: 31.347[5] mas/yr
Dec.: -61.766[5] mas/yr
Parallax (π)7.4137 ± 0.024[5] mas
Distance432.08 ly
(132.54 pc)
Absolute magnitude (MV)0.16[1]
Details
Mass2.5[3] M☉
Radius10.28±0.14[6] R☉
Luminosity77.62[7][lower-alpha 1] L☉
Surface gravity (log g)2.6866[5] cgs
Temperature5281±22[6] K
Metallicity [Fe/H]–0.4[7] dex
Rotational velocity (v sin i)7.53[4] km/s
Age660.7[3][lower-alpha 2] Myr
Other designations
BD+58 1224, Gaia DR2 1046383298937140864, HIP 48802, HR 3922, PPM 32387, TYC 3817-1649-1, GSC 03817-01649, IRAS 09537+5739
Database references
SIMBADdata

HD 85945 (HR 3922) is a star in the constellation Ursa Major. It is a yellow giant star with a spectral type of G6III:Fe-0.5. Based on information from Gaia DR3, it is located 132.54 parsecs (432.3 ly) from Earth and is moving towards Earth at a velocity of 47 km/s. It has an apparent magnitude of 5.96, which makes it faintly visible to the naked eye.

Characteristics

It is an evolved G-type giant star, based on its spectral type of G6III:Fe-0.5, which also indicates that it has a [Fe/H] metallicity of -0.5.[2] HD 85945 is 2.5 times more massive than the Sun and has expanded to 10.28 times the Sun's size.[3][6] It is emitting 78 times the solar luminosity from its photosphere at an effective temperature of 5,281 K.[7][6] Currently, the star is located in the horizontal branch stage of evolution.[3] The age of HD 85945 is estimated at 660 million years,[3] and it rotates under its axis at a speed of 7.53 km/s.[4] It is slightly metal-poor compared to the Sun, with an abundance of iron equivalent to 40% of the solar abundance.[7][lower-alpha 3]

HD 85945 is located within the Ursa Major constellation. The distance to HD 85945 is of 132.54 parsecs (432.3 ly), based on spectra from Gaia DR3.[5] The apparent magnitude of the star is of 5.96,[2] which is brighter than the limiting magnitude for naked-eye vision (6.5m), making it faintly visible to the naked eye.[8] The absolute magnitude, i.e. the brightness of the star if it was seen at a distance of 10 parsecs (32.6 ly), is 0.32.[9] At the current distance, its brightness is diminished by 0.03 magnitudes due to interstellar extinction between Earth and the star.[6] HD 85945 is moving away from Earth at a velocity of 46.55 km/s.[5] It has a high proper motion in the sky.[6][2]

Notes

  1. ↑ From a logarithm of 1.62.
  2. ↑ from a logarithm of 8.82.
  3. ↑ From a logarithm of -0.4

References

  1. ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  2. ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 "HD 85945". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+85945. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Stock, Stephan; Reffert, Sabine; Quirrenbach, Andreas (2018-08-01). "Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search". Astronomy and Astrophysics 616: A33. doi:10.1051/0004-6361/201833111. ISSN 0004-6361. Bibcode: 2018A&A...616A..33S. https://ui.adsabs.harvard.edu/abs/2018A&A...616A..33S.  Data about this star is available here in VizieR.
  4. ↑ 4.0 4.1 4.2 Hekker, S.; Meléndez, J. (2007-12-01). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics 475 (3): 1003–1009. doi:10.1051/0004-6361:20078233. ISSN 0004-6361. Bibcode: 2007A&A...475.1003H. https://ui.adsabs.harvard.edu/abs/2007A&A...475.1003H.  Data about this star is avalilable here in VizieR.
  5. ↑ 5.0 5.1 5.2 5.3 5.4 5.5 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.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Ren, J. -J.; Raddi, R.; Rebassa-Mansergas, A.; Hernandez, M. S.; Parsons, S. G.; Irawati, P.; Rittipruk, P.; Schreiber, M. R. et al. (2020-12-01). "The White Dwarf Binary Pathways Survey. V. The Gaia White Dwarf Plus AFGK Binary Sample and the Identification of 23 Close Binaries". The Astrophysical Journal 905 (1): 38. doi:10.3847/1538-4357/abc017. ISSN 0004-637X. Bibcode: 2020ApJ...905...38R.  Data about this star is available here in VizieR.
  7. ↑ 7.0 7.1 7.2 7.3 Charbonnel, C.; Lagarde, N.; Jasniewicz, G.; North, P. L.; Shetrone, M.; Krugler Hollek, J.; Smith, V. V.; Smiljanic, R. et al. (2020-01-01). "Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era". Astronomy and Astrophysics 633: A34. doi:10.1051/0004-6361/201936360. ISSN 0004-6361. Bibcode: 2020A&A...633A..34C. https://ui.adsabs.harvard.edu/abs/2020A&A...633A..34C.  Data about this star is available here in VizieR.
  8. ↑ "University Lowbrow Astronomers Naked Eye Observer's Guide.". https://websites.umich.edu/~lowbrows/guide/eye.html. 
  9. ↑ Ford, Dominic. "HIP-48802 (Star)" (in en). https://in-the-sky.org//data/object.php?id=TYC3817-1649-1. 



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