W Ursae Majoris

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Double star
W Ursae Majoris
W UMa Suchkarte.gif
Search card for W UMa
AladinLite
Observation
dates equinox :  J2000.0 , epoch : J2000.0
Constellation Big Bear
Right ascension 09 h 43 m 45.47 s
declination + 55 ° 57 ′ 9.1 ″
Apparent brightness 7.75 (7.75 to 8.48) mag
Typing
B − V color index +0.79 
Spectral class F8Vp + F8Vp
Variable star type EW / KW 
Astrometry
Radial velocity (−29.6 ± 1.2) km / s
parallax (19.28 ± 0.03)  mas
distance (169.09 ± 0.26)  Lj
(51.87 ± 0.09)  pc
Proper movement 
Rec. Share: (+17.15 ± 0.05)  mas / a
Dec. portion: (−29.23 ± 0.05)  mas / a
Physical Properties
Dimensions (1.19 / 0.57)  M ☉
radius (1.08 / 0.78)  R ☉
Other names
and catalog entries
Bonn survey BD + 56 ° 1400
Henry Draper Catalog HD 83950 [1]
Hipparcos catalog HIP 47727 [2]
SAO catalog SAO 27364 [3]
Tycho catalog TYC 3810-1210-1 [4]Template: Infobox star / maintenance / specification of the TYC catalog
2MASS catalog 2MASS J09434548 + 5557091 [5]
Other names AAVSO 0936 + 56 • ADS 7494

W Ursae Majoris ( W UMa ) is an eclipsing star in the constellation Ursa Major . He is the prototype of the W Ursae Majoris stars .

Its light change was discovered by the two astronomers Müller and Kempf during a zone observation for the Potsdam photometric survey in 1904.

W UMa is a contact system, whereby both stars have a common shell and exchange matter through gas flows. The period is 0.33363749 days.

Web links

Individual evidence

  1. ↑ a b c d e f W UMa. In: SIMBAD . Center de Données astronomiques de Strasbourg , accessed on November 2, 2018 .
  2. ↑ a b c W UMa. In: VSX. AAVSO, accessed November 2, 2018 .
  3. ↑ S. Bilir, Y. Karataş, O. Demircan, Eker, Z .: Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation . In: Monthly Notices of the Royal Astronomical Society . 357, No. 2, February 2005, pp. 497-517. arxiv : astro-ph / 0411291 . bibcode : 2005MNRAS.357..497B . doi : 10.1111 / j.1365-2966.2005.08609.x .
  4. ↑ K. Gazeas, K. Stȩpień: Angular momentum and mass evolution of contact binaries . In: Monthly Notices of the Royal Astronomical Society . 390, No. 4, November 2008, pp. 1577-1586. arxiv : 0803.0212 . bibcode : 2008MNRAS.390.1577G . doi : 10.1111 / j.1365-2966.2008.13844.x .