Decretion disk

In astronomy, a decretion disk describes a disk around a star that is fed by the star. This is different from an accretion disk , which transfers matter from outside to the star.

Decretion disks are temporarily observed around Be stars . These stars rotate at speeds close to the stability limit and even small disturbances lead to an outflow of matter along the stars' plane of rotation. The ejected matter remains in the star's gravitational field and forms a geometrically thin disk. Due to the internal friction in the disk, torque is reduced and the matter sinks back onto the star. In addition, these early stars show strong stellar winds that pull material from the surface of the disk.

Individual evidence

^ AO Simon, AV Bondar, NV Metlova: Spectral Evidence for Appearance of New Decretion Disk Around IGR J06074 + 2205 . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1211.4988 .
↑ J. Krticka, SP Owocki and G. Meynet: Mass and angular momentum loss via decretion disks . In: Astrophysics. Solar and Stellar Astrophysics . 2011, arxiv : 1101.1732 .

[1] AO Simon, AV Bondar, NV Metlova: Spectral Evidence for Appearance of New Decretion Disk Around IGR J06074 + 2205 . In: Astrophysics. Solar and Stellar Astrophysics . 2012, arxiv : 1211.4988 .

[2] J. Krticka, SP Owocki and G. Meynet: Mass and angular momentum loss via decretion disks . In: Astrophysics. Solar and Stellar Astrophysics . 2011, arxiv : 1101.1732 .