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Binary system in the constellation Ursa Major
Omega Ursae Majoris (Omega UMa , ω Ursae Majoris , ω UMa ) is the
Bayer designation for a
binary star system in the northern
circumpolar
constellation of
Ursa Major . It is visible to the naked eye with an
apparent visual magnitude of 4.61.
[2] Based upon an annual
parallax shift of 13.24
mas ,
[1] it is roughly 246
light years from the
Sun . At that distance, the visual magnitude of the star is diminished by an
extinction factor of 0.11 due to
interstellar dust .
[6]
This is a single-lined
spectroscopic binary star system with an
orbital period of 15.8 days and an
eccentricity of 0.31.
[7] The primary member, component A, is an
A-type main sequence star with a
stellar classification of A1VsSi:.
[3] The
stellar spectrum has the appearance of a hot
Am star , showing overabundances of many
iron-peak and heavier elements, but an underabundance of helium.
[12] In particular, it has an abnormal abundance of silicon.
[13]
Naming
In
Chinese , 天牢 (Tiān Láo ), meaning
Celestial Prison , refers to an asterism consisting of ω Ursae Majoris,
57 Ursae Majoris ,
47 Ursae Majoris ,
58 Ursae Majoris ,
49 Ursae Majoris and
56 Ursae Majoris . Consequently, the
Chinese name for ω Ursae Majoris itself is 天牢一 (Tiān Láo yī , English: the First Star of Celestial Prison .).
[14]
References
^
a
b
c
d
e
f 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 .
^
a
b
c
d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data ,
SIMBAD ,
Bibcode :
1986EgUBV........0M .
^
a
b Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal , 74 : 375–406,
Bibcode :
1969AJ.....74..375C ,
doi :
10.1086/110819 .
^
a
b Adelman, S. J. (2005), "The physical properties of normal a stars", Proceedings of the International Astronomical Union , 2004 : 1–11,
Bibcode :
2004IAUS..224....1A ,
doi :
10.1017/S1743921304004314 .
^ 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.
^
a
b
c Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters , 38 (11): 694–706,
arXiv :
1606.09028 ,
Bibcode :
2012AstL...38..694G ,
doi :
10.1134/S1063773712110035 ,
S2CID
119108982 .
^
a
b Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; et al. (2004), "SB9 : The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics , 424 (2): 727–732,
arXiv :
astro-ph/0406573 ,
Bibcode :
2004A&A...424..727P ,
doi :
10.1051/0004-6361:20041213 ,
S2CID
119387088 .
^ Pasinetti-Fracassini, L. E.; et al. (February 2001), "Catalog of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics , 367 (3rd ed.): 521–524,
arXiv :
astro-ph/0012289 ,
Bibcode :
2001A&A...367..521P ,
doi :
10.1051/0004-6361:20000451 ,
S2CID
425754 .
^
a
b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society , 427 (1): 343–57,
arXiv :
1208.2037 ,
Bibcode :
2012MNRAS.427..343M ,
doi :
10.1111/j.1365-2966.2012.21873.x ,
S2CID
118665352 .
^ Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics , 463 (2): 671–682,
arXiv :
astro-ph/0610785 ,
Bibcode :
2007A&A...463..671R ,
doi :
10.1051/0004-6361:20065224 ,
S2CID
18475298 .
^
"* ome UMa" ,
SIMBAD ,
Centre de données astronomiques de Strasbourg , retrieved 2017-02-22 .
^ Caliskan, Hulya; Adelman, Saul J. (June 1997), "Elemental abundance analyses with DAO spectrograms - XVII. The superficially normal early A stars 2 Lyncis, omicron Ursa Majoris and phiAquilae", Monthly Notices of the Royal Astronomical Society , 288 (2): 501–511,
Bibcode :
1997MNRAS.288..501C ,
doi :
10.1093/mnras/288.2.501 .
^ Renson, P.; Manfroid, J. (May 2009),
"Catalogue of Ap, HgMn and Am stars" , Astronomy and Astrophysics , 498 (3): 961–966,
Bibcode :
2009A&A...498..961R ,
doi :
10.1051/0004-6361/200810788 .
^ (in Chinese)
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