Disk Winds from T Tauri Stars
Abstract
We examine the observed characteristics of the low-velocity emission of forbidden lines in T Tauri stars and present arguments for a disk wind origin for that emission. Using the representative values of observed line luminosities and ratios, we find that the ionization fraction in the [O I] λ5577 emission region is high, ∼0.1, and that the mass-loss rate in the disk wind is considerably smaller than the mass accretion rate in the disk. Assuming that the disk wind is caused by a torque exerted by the magnetic field in the disk, we obtain relations between the properties of the disk wind and the magnetic field parameters at the base of the wind. We find that the product Bφ Bζ has a typical magnitude of ∼0.4 G2 at r = 1013 cm and that centrifugal flinging via magnetic acceleration is needed to propel the wind. However, a large portion of the energy available from accretion is lost, because of heating and ionization of the gas while it is being accelerated, to radiation.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1995
- DOI:
- 10.1086/176489
- Bibcode:
- 1995ApJ...454..382K
- Keywords:
-
- ACCRETION;
- ACCRETION DISKS;
- STARS: CIRCUMSTELLAR MATTER;
- STARS: MASS LOSS;
- STARS: PRE-MAIN-SEQUENCE