VLTI/AMBER unveils a possible dusty pinwheel nebula in WR118
Abstract
Context: Most Wolf-Rayet stars (WR) of the WC9 subtype exhibit a dusty circumstellar envelope, but it is still a matter of debate how dust can form in their harsh environment. In a few cases, a pinwheel-like structure of the dusty envelope has been detected; therefore, it has been suggested that dust formation in all dusty WR stars might be linked to colliding winds in a binary system.
Aims: We probed the innermost region of the circumstellar dust shell of the deeply embedded WR star
Methods: We carried out spectro-interferometric observations using the AMBER instrument of ESO's Very Large Telescope Interferometer in low-spectral resolution mode (R=35). The K-band observations were obtained with three 1.8 m telescopes spanning projected baselines between 9.2 and 40.1 m.
Results: At high spatial frequencies, the AMBER visibilities exhibit a prominent lobe, indicating that the envelope contains one or several zones with a large local intensity gradient. The strong closure phase signal clearly shows that the circumstellar envelope of
Conclusions:
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 2009
- DOI:
- 10.1051/0004-6361/200912992
- arXiv:
- arXiv:0909.4207
- Bibcode:
- 2009A&A...506L..49M
- Keywords:
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- stars: individual: <ASTROBJ>WR 118</ASTROBJ>;
- stars: Wolf-Rayet;
- stars: winds;
- outflows;
- stars: circumstellar matter;
- techniques: interferometric;
- techniques: spectroscopic;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Letter accepted in A&