Beta Lyrae Star

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As Beta Lyrae stars ( GCVS -Systematikkürzel: EB ) is a group of eclipsing stars whose occupation of the light curve varies continuously and its main and secondary minima have different depths. The continuous change in brightness is a result of the close proximity in the close binary star system , in which tidal forces deform the stars.

The classification according to the shape of the light curve has the disadvantage that it is not a classification based on physical properties and in the case of beta-lyrae stars there is also a dependency on the measurement accuracy. Coverage variables are preferably divided into separate, semi-separate and contact systems based on the geometry of the Roche boundary . The Beta Lyrae stars can be of all three types.

With EBs there is a dependency between the age and the period of the orbit. According to this, the mean period in star clusters decreases from 2 days at the age of some 10 million years to less than 0.5 days at the age of 10 billion years. The cause is unknown and the W-Ursae-Majoris contact systems do not show a corresponding development. Former Beta Lyrae star V1309 Sco has evolved into a Luminous Red Nova in a star merger and therefore EBs appear to be losing torque.

Occurrence in star catalogs

The General Catalog of Variable Stars currently lists around 1500 stars with the abbreviation EB , which means that 3% of all stars in this catalog belong to the Beta Lyrae class.

Examples

Individual evidence

  1. ^ Cuno Hoffmeister , G. Richter, W. Wenzel: Veränderliche Sterne . JA Barth Verlag, Leipzig 1990, ISBN 3-335-00224-5 .
  2. ^ John R. Percy: Understanding Variable Stars . Cambridge University Press, Cambridge 2007, ISBN 978-0-521-23253-1 .
  3. ↑ L. Bukowiecki, G. Maciejewski, P Konorski, R Errmann: Period-Age Correlations For Eclipsing Binaries In Stellar Clusters . In: Information Bulletin On Variable Stars . tape 6021 . Budapest 2012.
  4. ↑ R. Tylenda, M. Hajduk, T. Kamiński, A. Udalski, I. Soszyński, M. K Szymański, M. Kubiak, G. Pietrzyński, R. Poleski, Ł Wyrzykowski, K. Ulaczyk: V1309 Scorpii: merger of a contact binary . In: Astrophysics. Solar and Stellar Astrophysics . November 1, 2010, arxiv : 1012.0163 .
  5. ↑ Variability types General Catalog of Variable Stars, Sternberg Astronomical Institute, Moscow, Russia. Retrieved September 1, 2019 .