Transitional Disk
A Transitional Disk ( German translation: interface washer ) is a protoplanetary disk to a young stellar object with a dust-free inner hole or gap in the spacing of a few astronomical units ; in its outer area, corresponding to a radius of more than 10 AU, the pane is still rich in gas and dust. Transitional disks are also referred to by some authors as transition disks , weak disks , anemic disks (pale disks) or weak excess disks . They make up about 15 percent of the population of the protoplanetary disks.
One or more gaps in protoplanetary disks as well as transition disks, the inner area of which is almost completely free of dust, could be observed with the help of interferometric observations in nearby star formation regions such as the Taurus - Auriga complex. An accretion of gas onto the young star can still be detected in many cases.
At T-Tauri stars
Among the T-Tauri stars there is a group with a different spectral energy distribution : while the majority show a pronounced infrared excess in the entire range of infrared radiation , no excess can be detected in the near infrared in the range of 5 to 50 micrometers for some ; instead, an energy distribution like that of the photosphere of older stars is observed here. At longer wavelengths there is again a clear excess of infrared radiation. T-Tauri stars with transitional disks have a characteristic age of less than 10 million years.
Educational mechanisms
The following mechanisms are discussed for the dissolution of the inner parts of a protoplanetary disk:
- Photoevaporation from the young star's UV radiation
- the growth of dust particles through coagulation
- dynamic effects through stellar or planetary companions
- Formation and migration of gas planets .
Examples
Transitional disks have been proven to be
- LkCa 15 with the planet LkCa 15b
- DM dew
- GM Aur
- UX Tau A.
Individual evidence
- ^ S. Bruderer: Survival of molecular gas in cavities of transition disks (I. CO) . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1308.2966v1 .
- ↑ Andrea Isella, Laura M. Pe'rez, John M. Carpenter, Luca Ricci, Sean Andrews, Katherine Rosenfeld: An azimuthal asymmetry in the LkHa 330 disk . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1307.5848v1 .
- ^ Tobias WA Müller, Wilhelm Kley: Modeling Accretion in Transitional Disks . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1310.4398v1 .
- ↑ Aurora Sicilia-Aguilar, Jinyoung Serena Kim, Andrej Sobolev, Konstantin Getman, Thomas Henning, Min Fang: The low-mass stellar population in the young cluster Tr37: Disk evolution, accretion, and environment . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1308.0114v1 .
- ^ Jack Dobinson, Zoë M. Leinhardt, Sarah E. Dodson-Robinson, Nick A. Teanby: Hiding in the Shadows: Searching for Planets in Pre-transitional and Transitional Disks . In: Astrophysics. Solar and Stellar Astrophysics . 2013, arxiv : 1309.6480v2 .