Beta Lyrae
Sheliak ( from Arabic الشلياق, DMG aš - šiliyāq ), better known as β Lyrae (Beta Lyrae ) is about 900 light years distant star system in the constellation Lyra.
Sheliak is the namesake of the β Lyrae stars, a class of eclipsing binaries whose components are so close together that they deform elliptically by their mutual gravity. Sheliak changed its apparent brightness by with a period of 12.9075 days between 3.4 and 4.6 might like.
In the main star is a spectroscopic binary; its two components (Aa and Ab) are so close together that they can not be resolved with optical telescopes. However, they can be detected spectroscopically: In the mutual rotation of the star, a Doppler effect occurs, thereby shifting their spectral lines periodically.
The primary star is a B6- B8II giant with a mass of 8 solar masses, the mass of a B0.5V loses companion with a mass transfer rate of 10-5 solar masses per year. The companion can not be observed directly, because it is obscured by an accretion disk. However, its mass could be estimated at 12.5 solar masses. In addition, has been proved by interferometry as a result of accretion of a jet or bipolar outflow. Furthermore shortened due to the mass transfer, the period of the binary system at 19 seconds per year.
The system includes the two additional visual components B and F. The component B is located at a distance of 45.7 " at a position angle of 149 °, it is of spectral type B5, has an apparent magnitude of 7.1 may and can already be seen in the prism binoculars. component F is at a position angle of 19 ° at an angular distance of 85.8 " and has an apparent magnitude of 10.6 mag. Three other potential components (C, D and E) do not seem physically associated with the system.
Itemization
- Lyra ( constellation )
- Individual fourth star size
- Triple-star
- Variable star