Probing T Tauri Accretion and Outflow with 1 Micron Spectroscopy
Abstract
In a high-dispersion 1 μm survey of 39 classical T Tauri stars (CTTSs) veiling is detected in 80% of the stars, and He I λ10830 and Pγ line emission in 97%. On average, the 1 μm veiling exceeds the level expected from previously identified sources of excess emission, suggesting the presence of an additional contributor to accretion luminosity in the star-disk interface region. Strengths of both lines correlate with veiling, and at Pγ there is a systematic progression in profile morphology with veiling. He I λ10830 has an unprecedented sensitivity to inner winds, showing blueshifted absorption below the continuum in 71% of the CTTSs, compared to 0% at Pγ. This line is also sensitive to magnetospheric accretion flows, with redshifted absorption below the continuum found in 47% of the CTTSs, compared to 24% at Pγ. The blueshifted absorption at He I λ10830 shows considerable diversity in its breadth and penetration depth into the continuum, indicating that a range of inner wind conditions exist in accreting stars. We interpret the broadest and deepest blue absorptions as formed from scattering of the 1 μm continuum by outflowing gas whose full acceleration region envelopes the star, suggesting radial outflow from the star. In contrast, narrow blue absorption with a range of radial velocities more likely arises via scattering of the 1 μm continuum by a wind emerging from the inner disk. Both stellar and disk winds are accretion powered, since neither is seen in nonaccreting WTTSs and among the CTTSs helium strength correlates with veiling.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 2006
- DOI:
- 10.1086/504832
- arXiv:
- arXiv:astro-ph/0604006
- Bibcode:
- 2006ApJ...646..319E
- Keywords:
-
- Stars: Planetary Systems: Protoplanetary Disks;
- Stars: Formation;
- Stars: Pre-Main-Sequence;
- Stars: Winds;
- Outflows;
- Astrophysics
- E-Print:
- 55 pages, including 16 figures. Astrophysical Journal, accepted