HD 39225

HD 39225

Observation data Epoch J2000      Equinox J2000
Constellation	Auriga
Right ascension	05^h 52^m 40.09222^s[1]
Declination	+33° 55′ 02.8721″[1]
Apparent magnitude (V)	6.04[2] (5.82–6.07)[3]
Characteristics
Evolutionary stage	AGB[4]
Spectral type	M1+III Fe-1[5]
U−B color index	1.97
B−V color index	1.579±0.021
Variable type	suspected[3]
Astrometry
Radial velocity (Rv)	98.35±0.53[1] km/s
Proper motion (μ)	RA: 18.569[1] mas/yr Dec.: 8.812[1] mas/yr
Parallax (π)	5.2412 ± 0.1841 mas[1]
Distance	620 ± 20 ly (191 ± 7 pc)
Absolute magnitude (MV)	−0.77[2]
Details
Radius	43.0±3.5[1] R☉
Luminosity	398.6±16.2[1] L☉
Temperature	3,934±51[6] K
Other designations
BD+33°1179, HD 39225, HIP 27778, HR 2028, SAO 58528, GSC 02414-00524[7]
Database references
SIMBAD	data

HD 39225, also known as HR 2028, is a variable star in the northern constellation Auriga, located around 620 light years away from the Sun. It is visible to the naked eye as a faint, red-hued star with an apparent visual magnitude of around 6.04.^[2] This is a suspected runaway star^[8] that is moving away from the Sun with a heliocentric radial velocity of 98 km/s.^[1]

Currently on the asymptotic giant branch,^[4] this is an evolved red giant star with a stellar classification of M1+III Fe-1.^[5] The suffix notation indicates an underabundance of iron in the stellar atmosphere compared to similar stars of its class. It is suspected of varying in brightness between magnitudes 5.82 and 6.07.^[3] Having exhausted the hydrogen at its core, it has expanded to around 43 times the Sun's radius.^[1] It shines with a luminosity approximately 398.6^[1] times that of the Sun and has a surface temperature of 3,934 K.^[6]

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
3. Watson, Christopher (18 January 2010). "NSV 2681". The International Variable Star Index. American Association of Variable Star Observers. Retrieved 28 June 2015.
4. Eggen, Olin J. (1992). "Asymptotic giant branch stars near the sun". The Astronomical Journal. 104: 275. Bibcode:1992AJ....104..275E. doi:10.1086/116239.
5. Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
6. van Belle, G. T.; et al. (2009). "Supergiant temperatures and linear radii from near-infrared interferometry". Monthly Notices of the Royal Astronomical Society. 394 (4): 1925. arXiv:0811.4239. Bibcode:2009MNRAS.394.1925V. doi:10.1111/j.1365-2966.2008.14146.x. S2CID 118372600.
7. "HD 39225". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-03-30.
8. Tetzlaff, N.; et al. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873.