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61 Ursae Majoris

Summary

61 Ursae Majoris, abbreviated 61 UMa, is a single[13] star in the northern circumpolar constellation of Ursa Major. It has a yellow-orange hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.35.[2] The distance to this star is 31.2 light years based on parallax,[1] and it is drifting closer with a radial velocity of −5.2 km/s.[6] The star has a relatively high proper motion traversing the sky at the rate of 0.381″ yr−1.[14]

61 Ursae Majoris
Observation data
Epoch J2000      Equinox J2000
Constellation Ursa Major
Right ascension 11h 41m 03.01594s[1]
Declination +34° 12′ 05.8824″[1]
Apparent magnitude (V) 5.35[2]
Characteristics
Evolutionary stage Main sequence[3]
Spectral type G8V[4]
U−B color index +0.27[5]
B−V color index +0.69[5]
Variable type Suspected
Astrometry
Radial velocity (Rv)−5.18±0.08[6] km/s
Proper motion (μ) RA: −12.247[1] mas/yr
Dec.: −381.257[1] mas/yr
Parallax (π)104.3904 ± 0.1287 mas[1]
Distance31.24 ± 0.04 ly
(9.58 ± 0.01 pc)
Absolute magnitude (MV)5.53±0.006[7]
Details
Mass0.93±0.02[8] M☉
Radius0.86±0.02[9] R☉
Luminosity0.609±0.009[10] L☉
Surface gravity (log g)4.43±0.06[3] cgs
Temperature5,488±44[3] K
Metallicity [Fe/H]−0.03±0.03[3] dex
Rotation17.1 days[11]
Rotational velocity (v sin i)3.3[3] km/s
Age2.1±1.7[8] Gyr
Other designations
61 UMa, NSV 5291, BD+35°2270, FK5 1300, GJ 434, HD 101501, HIP 56997, HR 4496, SAO 62655, WDS J11411+3412A, LTT 13200[12]
Database references
SIMBADdata

The stellar classification of 61 UMa is G8V,[4] matching a late G-type main-sequence star. Since 1943, the spectrum of this star has served as one of the stable anchor points by which other stars are classified.[15] It is considered a solar-type star, having physical properties that make it similar to the Sun.[16] The star has 93%[8] of the mass of the Sun and 86%[9] of the Sun's radius. It is roughly two[8] billion years old and is spinning with a projected rotational velocity of 3.3 km/s,[3] for a period of 17.1 days.[11] The metallicity, or abundance of elements with higher atomic number than helium, appears about the same as in the Sun.[3] The star is radiating 61%[10] of the luminosity of the Sun from its photosphere at an effective temperature of 5,488K.[3]

During the 1950s, Karl Pilowski reported that photographic plates taken of the star appeared to show a variability of 0.2 in magnitude. Follow-up studies initially failed to confirm this variability, and it was found not to be an eclipsing binary based on radial velocity measurements.[17] The star's photosphere is rotating differentially, and the rotation period, typically in the range of 16-18 days, shows a larger difference between different latitudes than for most other stars.[18] It has an active chromosphere that exhibits strong and persistent starspot activity.[9] A flare event was captured in 2013 while the star was being observed by the VATT,[19] and the star has been detected as a source of X-ray emission.[20]

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. A radial velocity survey completed in 2020 has indicated that giant planetary companions are absent.[9] A magnitude 11.35 stellar visual companion was reported by O. Struve in 1850. As of 2015, this star was located at an angular separation of 158.90″ from the brighter star, along a position angle of 86°.[21]

In popular culture edit

In the science fiction of Larry Niven's Known Space universe, the homeworld of the major race the Kzinti is the third planet in orbit around 61 Ursae Majoris.[22]

In the Star Trek universe, Archer IV is the fourth planet around 61 Ursae Majoris.[23]

References edit

  1. ^ a b c d e f 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. ^ a b 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. S2CID 120792029.
  3. ^ a b c d e f g h Marfil, E.; et al. (March 2020). "Stellar atmospheric parameters of FGK-type stars from high-resolution optical and near-infrared CARMENES spectra". Monthly Notices of the Royal Astronomical Society. 492 (4): 5470–5507. arXiv:2001.01495. Bibcode:2020MNRAS.492.5470M. doi:10.1093/mnras/staa058.
  4. ^ a b 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.
  5. ^ 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.
  6. ^ a b Nidever, David L.; et al. (August 2002). "Radial Velocities for 889 Late-Type Stars". The Astrophysical Journal Supplement Series. 141 (2): 503–522. arXiv:astro-ph/0112477. Bibcode:2002ApJS..141..503N. doi:10.1086/340570. S2CID 51814894.
  7. ^ 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. S2CID 119187733.
  8. ^ a b c d Chavero, C.; et al. (August 2019). "Emerging trends in metallicity and lithium properties of debris disc stars". Monthly Notices of the Royal Astronomical Society. 487 (3): 3162–3177. arXiv:1905.12066. Bibcode:2019MNRAS.487.3162C. doi:10.1093/mnras/stz1496.
  9. ^ a b c d Cabot, Samuel H. C.; et al. (January 2021). "EXPRES. II. Searching for Planets around Active Stars: A Case Study of HD 101501". The Astronomical Journal. 161 (1): 20. arXiv:2010.14717. Bibcode:2021AJ....161...26C. doi:10.3847/1538-3881/abc41e. S2CID 225094601. 26.
  10. ^ a b 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. S2CID 18993744. See Table 10.
  11. ^ a b 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. S2CID 119209183.
  12. ^ "61 UMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-31.
  13. ^ Fuhrmann, K.; et al. (February 2017). "Multiplicity among Solar-type Stars". The Astrophysical Journal. 836 (1): 23. Bibcode:2017ApJ...836..139F. doi:10.3847/1538-4357/836/1/139. 139.
  14. ^ Lépine, Sébastien; Shara, Michael M. (March 2005). "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)". The Astronomical Journal. 129 (3): 1483–1522. arXiv:astro-ph/0412070. Bibcode:2005AJ....129.1483L. doi:10.1086/427854. S2CID 2603568.
  15. ^ 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. Archived from the original on 2019-06-25. Retrieved 2012-02-04.
  16. ^ de Mello, G. F. Porto; et al. (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. S2CID 119459291.
  17. ^ Haupt, Hermann (August 1953). "Radial Velocity Observations of 61 Ursae Majoris". Publications of the Astronomical Society of the Pacific. 65 (385): 219. Bibcode:1953PASP...65..219H. doi:10.1086/126602.
  18. ^ Mittag, M.; et al. (November 2017). "Stellar rotation periods determined from simultaneously measured Ca II H&K and Ca II IRT lines". Astronomy & Astrophysics. 607: 39. Bibcode:2017A&A...607A..87M. doi:10.1051/0004-6361/201630262. A87.
  19. ^ Corbally, Christopher J.; et al. (January 2015). van Belle, G.; Harris, H. C. (eds.). Short-term Activity in Young Solar Analogs. 18th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Proceedings of the conference held at Lowell Observatory, 8-14 June, 2014. pp. 307–312. Bibcode:2015csss...18..307C.
  20. ^ Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009). "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources". The Astrophysical Journal Supplement. 184 (1): 138–151. arXiv:0910.3229. Bibcode:2009ApJS..184..138H. doi:10.1088/0067-0049/184/1/138. S2CID 119267456.
  21. ^ Mason, B. D.; et al. (2014). "The Washington Visual Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
  22. ^ Niven, Larry (1970). Ringworld. Ballantine Books. chapters 2 and 6. ISBN 0-345-02046-4.
  23. ^ https://memory-alpha.fandom.com/wiki/Archer_IV

External links edit

  • "61 Ursae Majoris". SolStation. Archived from the original on 26 June 2006. Retrieved 2006-07-22.
  • "61 UMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2006-07-22.
  • "Gl 434". ARICNS. Archived from the original on 24 October 2005. Retrieved 2006-07-22.

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