61 Ursae Majoris

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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[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 mas[1]
Distance31.1 ± 0.2 ly
(9.54 ± 0.07 pc)
Absolute magnitude (MV)5.53±0.006[6]
Details
Mass0.85[7] M☉
Radius0.940 ± 0.010[8] R☉
Luminosity0.609 ± 0.009[8] L☉
Surface gravity (log g)4.69[2] cgs
Temperature5,270 ± 32[8] K
Metallicity [Fe/H]+0.03[2] dex
Rotation17.1 days[9]
Rotational velocity (v sin i)8[10] km/s
Age0.8–1.2[11] Gyr
Other designations
BD+35° 2270, FK5 1300, GCTP 2699.00, GJ 434, HD 101501, HIP 56997, HR 4496, LTT 13200, SAO 62655, NSV 5291.
Database references
SIMBADdata

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.[12]

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 (26×10^3 ly) from the core with an eccentricity of 0.06.[13]

See also

References

  1. ^ 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.
  2. ^ 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.
  3. ^ 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.
  4. ^ 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.
  5. ^ Wilson, Ralph Elmer (1953). General Catalogue of Stellar Radial Velocities. Washington: Carnegie Institution of Washington. Bibcode:1953GCRV..C......0W.
  6. ^ Park, Sunkyung; et al. (2013), "Wilson-Bappu Effect: Extended to Surface Gravity", The Astronomical Journal, 146 (4): 73, arXiv:1307.0592, Bibcode:2013AJ....146...73P, doi:10.1088/0004-6256/146/4/73.
  7. ^ 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. arXiv:astro-ph/0607235. Bibcode:2007ApJS..168..297T. doi:10.1086/509763. Note: see VizieR catalogue J/ApJS/168/297.
  8. ^ 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, arXiv:1112.3316, Bibcode:2012ApJ...746..101B, doi:10.1088/0004-637X/746/1/101. See Table 10.
  9. ^ 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
  10. ^ 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.
  11. ^ 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.
  12. ^ 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
  13. ^ 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

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