15 Ursae Majoris

15 Ursae Majoris is a star in the northern circumpolar constellation Ursa Major, located 94 light years away from the Sun.[1] It has the Bayer designation f Ursae Majoris; 15 Ursae Majoris is the Flamsteed designation. It is visible to the naked eye as a white-hued star with an apparent visual magnitude of 4.46.[2] 15 Ursae Majoris is a suspected member of the Castor stellar kinematic group, a 200 million year old association of co-moving stars.[10]

15 Ursae Majoris
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
Right ascension 09h 08m 52.25763s[1]
Declination +51° 36′ 16.7330″[1]
Apparent magnitude (V) 4.46[2]
Characteristics
Spectral type kA3VmF5IIISr[3]
B−V color index 0.288±0.013[2]
Astrometry
Radial velocity (Rv)−0.1±0.7[4] km/s
Proper motion (μ) RA: −136.33[1] mas/yr
Dec.: −32.60[1] mas/yr
Parallax (π)34.70 ± 0.24[1] mas
Distance94.0 ± 0.7 ly
(28.8 ± 0.2 pc)
Absolute magnitude (MV)2.16[2]
Details
Mass1.86[5] M☉
Radius1.3[6] R☉
Luminosity11.31[2] L☉
Surface gravity (log g)3.77±0.08[7] cgs
Temperature7,519±98[7] K
Metallicity [Fe/H]0.55±0.05[7] dex
Rotational velocity (v sin i)42[8] km/s
Age220[5] Myr
Other designations
f UMa, 15 UMa, BD+52°1365, FK5 2721, GJ 3534, HD 78209, HIP 44901, HR 3619, SAO 27136[9]
Database references
SIMBADdata

According to Eggleton and Tokovinin (2008), this is a suspected binary star system with an orbital period of 4.9 days and an eccentricity of 0.2.[11] However, De Rosa et al. (2014) did not find a companion.[5] The primary is metallic-lined (Am) star, meaning it has unusually strong absorption lines of metals in its spectrum. Classification of the spectrum is difficult due to the peculiarities. An MK classification of 15 UMa using the calcium K line is A3 V, but using metallic spectral lines it can appear as a cooler and more luminous star. Spectral lines in the blue region give a classification of F5 Ib, while in the violet region the lines suggest F5 III/IV.[3]

Nomenclature

With τ, h, υ Ursae Majoris, φ, θ dan e it composed the Arabic asterism Sarīr Banāt al-Na'sh, the Throne of the daughters of Na'sh, and Al-Haud, the Pond.[12] According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al-Haud were the title for seven stars : this star (f) as Alhaud I, τ as Alhaud II, e as Alhaud III, h as Alhaud IV, θ as Alhaud V, υ as Alhaud VI and φ as Alhaud VII.[13]

In Chinese, 文昌 (Wén Chāng), meaning Administrative Center, refers to an asterism consisting six stars, such as 15 Ursae Majoris, υ Ursae Majoris, θ Ursae Majoris and φ Ursae Majoris.[14][15]

References
  1. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  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. Sreedhar Rao, S.; Abhyankar, K. D. (1991). "MK morphological study of AM stars at 66 A/mm". Journal of Astrophysics and Astronomy. 12 (2): 133. Bibcode:1991JApA...12..133S. doi:10.1007/BF02709302. S2CID 59324843.
  4. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012). "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project". Astronomy & Astrophysics. 546: 14. arXiv:1208.3048. Bibcode:2012A&A...546A..61D. doi:10.1051/0004-6361/201219219. S2CID 59451347. A61.
  5. De Rosa, R. J.; Patience, J.; Wilson, P. A.; Schneider, A.; Wiktorowicz, S. J.; Vigan, A.; Marois, C.; Song, I.; MacIntosh, B.; Graham, J. R.; Doyon, R.; Bessell, M. S.; Thomas, S.; Lai, O. (2014). "The VAST Survey - III. The multiplicity of A-type stars within 75 pc". Monthly Notices of the Royal Astronomical Society. 437 (2): 1216. arXiv:1311.7141. Bibcode:2014MNRAS.437.1216D. doi:10.1093/mnras/stt1932. S2CID 88503488.
  6. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (Third ed.), 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  7. Prugniel, P.; et al. (2011). "The atmospheric parameters and spectral interpolator for the MILES stars". Astronomy & Astrophysics. 531: A165. arXiv:1104.4952. Bibcode:2011A&A...531A.165P. doi:10.1051/0004-6361/201116769. S2CID 54940439.
  8. Royer, F.; et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics, 393 (3): 897–911, arXiv:astro-ph/0205255, Bibcode:2002A&A...393..897R, doi:10.1051/0004-6361:20020943, S2CID 14070763
  9. "15 UMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-03-17.
  10. Nakajima, Tadashi; Morino, Jun-Ichi (2012). "Potential Members of Stellar Kinematic Groups within 30 pc of the Sun". The Astronomical Journal. 143 (1): 2. Bibcode:2012AJ....143....2N. doi:10.1088/0004-6256/143/1/2.
  11. Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  12. Allen, Richard Hinckley (1899), Star-Names and Their Meanings, New York: G. E. Stechert, p. 442
  13. Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF), Jet Propulsion Laboratory, California Institute of Technology.
  14. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 16 日
  15. Ian Ridpath's Startales - Ursa Major the Great Bear
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