61 Ursae Majoris
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 11h 41m 03.0153s[1] |
| Declination | +34° 12′ 05.888″[1] |
| Apparent magnitude (V) | 5.35[2] |
| Characteristics | |
| Spectral type | G8V[3] |
| U−B color index | +0.27[4] |
| B−V color index | +0.69[4] |
| R−I color index | 0.37 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | −5.4[5] km/s |
| Proper motion (μ) | RA: −13.95[1] mas/yr Dec.: −380.46[1] mas/yr |
| Parallax (π) | 104.81 ± 0.72[1] mas |
| Distance | 31.1 ± 0.2 ly (9.54 ± 0.07 pc) |
| Absolute magnitude (MV) | 5.41 |
| Details | |
| Mass | 0.85[6] M☉ |
| Radius | 0.940 ± 0.010[7] R☉ |
| Luminosity | 0.609 ± 0.009[7] L☉ |
| Surface gravity (log g) | 4.69[2] cgs |
| Temperature | 5,270 ± 32[7] K |
| Metallicity [Fe/H] | +0.03[2] dex |
| Rotation | 17.1 days[8] |
| Rotational velocity (v sin i) | 8[9] km/s |
| Age | 0.8–1.2[10] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
61 Ursae Majoris (61 UMa) is an orange-yellow G8 main-sequence star in the constellation Ursa Major. It is somewhat smaller and fainter than the Sun, and can just barely be seen by the unaided eye (based on a magnitude limit of 6). Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[11]
No substellar companions have been observed in orbit around this star, and it appears to lack a dust ring as is found around some comparable stars. It lies near the same line of sight as the sub-giant star HD 101212, although it is unclear whether these two stars are gravitationally bound or even in physical proximity.
The space velocity components of this star are [U, V, W] = [+8, −16, −4] km/s. It is orbiting the galaxy at a mean distance of 7.9 kpc (26×103 ly) from the core with an eccentricity of 0.06.[12]
See also
References
- 1 2 3 4 5 Perryman, M. A. C.; et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics. 323: L49–L52. Bibcode:1997A&A...323L..49P.
- 1 2 3 Cornide, M.; Rego, M. (October 1984). "Iron abundances in G dwarfs". Astrophysics and Space Science. 105 (1): 55–65. Bibcode:1984Ap&SS.105...55C. doi:10.1007/BF00651207.
- ↑ Wilson, O. C. (November 1962). "Relationship Between Colors and Spectra of Late Main-Sequence Stars". Astrophysical Journal. 136: 793. Bibcode:1962ApJ...136..793W. doi:10.1086/147437.
- 1 2 Johnson, H. L.; Morgan, W. W. (1953). "Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas". Astrophysical Journal. 117: 313–352. Bibcode:1953ApJ...117..313J. doi:10.1086/145697.
- ↑ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
- ↑ Takeda, G.; et al. (2007). "Stellar parameters of nearby cool stars. II. Physical properties of ~1000 cool stars from the SPOCS catalog". Astrophysical Journal Supplement Series. 168: 297–318. Bibcode:2008yCat..21680297T. doi:10.1086/509763. Note: see VizieR catalogue J/ApJS/168/297.
- 1 2 3 Boyajian, Tabetha S.; et al. (February 2012), "Stellar Diameters and Temperatures. I. Main-sequence A, F, and G Stars", The Astrophysical Journal, 746 (1): 101, arXiv:1112.3316
, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101. See Table 10. - ↑ Maldonado, J.; et al. (October 2010), "A spectroscopy study of nearby late-type stars, possible members of stellar kinematic groups", Astronomy and Astrophysics, 521: A12, arXiv:1007.1132, Bibcode:2010A&A...521A..12M, doi:10.1051/0004-6361/201014948
- ↑ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1). Bibcode:1970CoAsi.239....1B.
- ↑ Mamajek, Eric E.; Hillenbrand, Lynne A. (November 2008). "Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics". The Astrophysical Journal. 687 (2): 1264–1293. arXiv:0807.1686. Bibcode:2008ApJ...687.1264M. doi:10.1086/591785.
- ↑ Garrison, R. F. (December 1993), "Anchor Points for the MK System of Spectral Classification", Bulletin of the American Astronomical Society, 25: 1319, Bibcode:1993AAS...183.1710G, retrieved 2012-02-04
- ↑ de Mello, G. F. Porto; del Peloso, E. F.; Ghezzi, L. (2006). "Astrobiologically interesting stars within 10 parsecs of the Sun". Astrobiology. 6 (2): 308–331. arXiv:astro-ph/0511180. Bibcode:2006AsBio...6..308P. doi:10.1089/ast.2006.6.308. PMID 16689649. Retrieved 2008-01-17.
External links
- "61 Ursae Majoris". SolStation. Archived from the original on 26 June 2006. Retrieved 2006-07-22.
- "HD 101501". SIMBAD. Retrieved 2006-07-22.
- "Gl 434". ARICNS. Archived from the original on 24 October 2005. Retrieved 2006-07-22.
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