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HD 85945

Coordinates: Sky map 09h 57m 13.61s, +57° 25′ 05.54″
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HD 85945
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major[a]
Right ascension 09h 57m 13.61s[1]
Declination +57° 25′ 05.54″[1]
Apparent magnitude (V) 5.959±0.009[1]
Characteristics
Evolutionary stage Horizontal branch[2]
Spectral type G6III:Fe-0.5[1]
Apparent magnitude (B) 6.854±0.015[1]
Apparent magnitude (G) 5.733[1]
Apparent magnitude (J) 4.513±0.028[1]
Apparent magnitude (H) 4.141±0.036[1]
Apparent magnitude (K) 3.978±0.3[1]
B−V color index 0.895[3]
Astrometry
Radial velocity (Rv)−46.55±0.12[4] km/s
Proper motion (μ) RA: 31.347 mas/yr[4]
Dec.: -61.766 mas/yr[4]
Parallax (π)7.4137 ± 0.024 mas[4]
Distance432.08 ly
(132.54 pc)[4]
Absolute magnitude (MV)0.32[5]
Details
Mass2.5[2] M☉
Radius10.28±0.14[6] R☉
Luminosity77.62[7][b] L☉
Surface gravity (log g)2.6866[4] cgs
Temperature5281±22[6] K
Metallicity [Fe/H]–0.4[7] dex
Rotational velocity (v sin i)7.53[3] km/s
Age660.7[2][c] Myr
Other designations
BD+58 1224, Gaia DR2 1046383298937140864, Gaia DR3 1046383298937140864, HIP 48802, HR 3922, PPM 32387, TIC 377368616, 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

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It is an evolved G-type giant star, based on its spectral type of G6III:Fe-0.5, which also indicates that is has a [Fe/H] metallicity of -0.5.[1] HD 85945 is 2.5 times more massive than the Sun and has expanded to 10.28 times the Sun's size.[2][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.[2] The age of HD 85945 is estimated at 660 million years,[2] and it rotates under its axis at a speed of 7.53 km/s.[3] It is slightly metal-poor compared to the Sun, with an abundance of iron equivalent to 40% of the solar abundance.[7][d]

HD 85945 is located within the Ursa Major constellation, based on its celestial coordinates.[a] The distance to HD 85945 is of 132.54 parsecs (432.3 ly), based on spectra from Gaia DR3.[4] The apparent magnitude of the star is of 5.96,[1] 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.[5] 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.[4] It has a high proper motion in the sky.[6][1]

Notes

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  1. ^ a b Obtained with a right ascension of 09h 57m 13.61s and a declination of +57° 25′ 05.54″[1] on this website.
  2. ^ From a logarithm of 1.62.
  3. ^ from a logarithm of 8.82.
  4. ^ From a logarithm of -0.4

References

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  1. ^ a b c d e f g h i j k l m "HD 85945". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 7, 2024.
  2. ^ a b c d e f 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. arXiv:1805.04094. Bibcode:2018A&A...616A..33S. doi:10.1051/0004-6361/201833111. ISSN 0004-6361. Data about this star is available here in VizieR.
  3. ^ a b c Hekker, S.; Meléndez, J. (2007-12-01). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics. 475 (3): 1003–1009. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233. ISSN 0004-6361. Data about this star is avalilable here in VizieR.
  4. ^ a b c d e f g Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  5. ^ a b Ford, Dominic. "HIP-48802 (Star)". In-The-Sky.org. Retrieved 2024-05-07.
  6. ^ a b c d e f Ren, J. -J.; Raddi, R.; Rebassa-Mansergas, A.; Hernandez, M. S.; Parsons, S. G.; Irawati, P.; Rittipruk, P.; Schreiber, M. R.; Gänsicke, B. T.; Torres, S.; Wang, H. -J.; Zhang, J. -B.; Zhao, Y.; Zhou, Y. -T.; Han, Z. -W. (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. arXiv:2010.02885. Bibcode:2020ApJ...905...38R. doi:10.3847/1538-4357/abc017. ISSN 0004-637X. Data about this star is available here in VizieR.
  7. ^ a b c d Charbonnel, C.; Lagarde, N.; Jasniewicz, G.; North, P. L.; Shetrone, M.; Krugler Hollek, J.; Smith, V. V.; Smiljanic, R.; Palacios, A.; Ottoni, G. (2020-01-01). "Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era". Astronomy and Astrophysics. 633: A34. arXiv:1910.12732. Bibcode:2020A&A...633A..34C. doi:10.1051/0004-6361/201936360. ISSN 0004-6361. Data about this star is available here in VizieR.
  8. ^ "University Lowbrow Astronomers Naked Eye Observer's Guide". websites.umich.edu. Retrieved 2024-05-07.
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