61 Ursae Majoris
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| 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[citation needed] |
| 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] |
| 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 | |
61 Ursae Majoris (61 UMa) is an orange-yellow main sequence dwarf star in the constellation Ursa Major. This star 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 sub-stellar 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 presently 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 kly) from the core with an eccentricity of 0.06.[12]
[edit] See also
[edit] References
- ^ a b c d e Perryman, M. A. C.; et al. (April 1997). "The HIPPARCOS Catalogue". Astronomy & Astrophysics 323: L49–L52. Bibcode 1997A&A...323L..49P.
- ^ a b c 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.
- ^ a b 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 1953QB901.W495......
- ^ 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. Note: see VizieR catalogue J/ApJS/168/297.
- ^ a b c 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, 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, 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. 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, http://www.astro.utoronto.ca/~garrison/mkstds.html, 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.
[edit] External links
- "61 Ursae Majoris". SolStation. http://www.solstation.com/stars/61uma.htm. Retrieved 2006-07-22.
- "HD 101501". SIMBAD. http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=61+Ursae+Majoris&NbIdent=1&Radius=10&Radius.unit=arcmin&CooFrame=FK5&CooEpoch=2000&CooEqui=2000&output.max=all&o.catall=on&output.mesdisp=N&Bibyear1=1983&Bibyear2=2006&Frame1=FK5&Frame2=FK4&Frame3=G&Equi1=2000.0&Equi2=1950.0&Equi3=2000.0&Epoch1=2000.0&Epoch2=1950.0&Epoch3=2000.0. Retrieved 2006-07-22.
- "Gl 434". ARICNS. http://www.ari.uni-heidelberg.de/aricns/cnspages/4c00894.htm. Retrieved 2006-07-22.[dead link]
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