Revealing the inner circumstellar disk of the T Tauri star S Coronae Australis N using the VLTI
Abstract
Aims: We investigate the structure of the circumstellar disk of the T Tauri star S CrA N and test whether the observations agree with the standard picture proposed for Herbig Ae stars.
Methods: Our observations were carried out with the VLTI/AMBER instrument in the H and K bands with the low spectral resolution mode. For the interpretation of our near-infrared AMBER and archival mid-infrared MIDI visibilities, we employed both geometric and temperature-gradient models.
Results: To characterize the disk size, we first fitted geometric models consisting of a stellar point source, a ring-shaped disk, and a halo structure to the visibilities. In the H and K bands, we measured ring-fit radii of 0.73 ± 0.03 mas (corresponding to 0.095 ± 0.018 AU for a distance of 130 pc) and 0.85 ± 0.07 mas (0.111 ± 0.026 AU), respectively. This K-band radius is approximately two times larger than the dust sublimation radius of ≈0.05 AU expected for a dust sublimation temperature of 1500 K and gray dust opacities, but approximately agrees with the prediction of models including backwarming (namely a radius of ≈0.12 AU). The derived temperature-gradient models suggest that the disk is approximately face-on consisting of two disk components with a gap between star and disk. The inner disk component has a temperature close to the dust sublimation temperature and a quite narrow intensity distribution with a radial extension from 0.11 AU to 0.14 AU.
Conclusions: Both our geometric and temperature-gradient models suggest that the T Tauri star S CrA N is surrounded by a circumstellar disk that is truncated at an inner radius of ≈ 0.11 AU. The narrow extension of the inner temperature-gradient disk component implies that there is a hot inner rim.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- July 2012
- DOI:
- 10.1051/0004-6361/201218892
- arXiv:
- arXiv:1207.2467
- Bibcode:
- 2012A&A...543A.162V
- Keywords:
-
- stars: individual: S Coronae Australis N;
- stars: pre-main sequence;
- circumstellar matter;
- protoplanetary disks;
- accretion;
- accretion disks;
- techniques: interferometric;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for publication in A&