[OI] 6300A emission in herbig Ae/Be systems: Signature of Keplerian rotation
Feb, 2005
22 pages
Published in:
- Astron.Astrophys. 436 (2005) 209-230
e-Print:
- astro-ph/0502504 [astro-ph]
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Abstract: (arXiv)
We present high spectral-resolution optical spectra of 49 Herbig Ae/Be stars in a search for the [O I] 6300A line. The vast majority of the stars in our sample show narrow (FWHM < 100 km/s) emission lines, centered on the stellar radial velocity. In only three sources is the feature much broader (~400 km/s), and strongly blueshifted (-200 km/s) compared to the stellar radial velocity. Some stars in our sample show double-peaked lines profiles, with peak-to-peak separations of ~10 km/s. The presence and strength of the [O I] line emission appears to be correlated with the far-infrared energy distribution of each source: stars with a strong excess at 60 micron have in general stronger [O I] emission than stars with weaker 60 micron excesses. We interpret these narrow [O I] 6300A line profiles as arising in the surface layers of the protoplanetary disks surrounding Herbig Ae/Be stars. A simple model for [O I] 6300A line emission due to the photodissociation of OH molecules shows that our results are in quantitative agreement with that expected from the emission of a flared disk if the fractional OH abundance is ~5 x 10^{-7}.- CIRCUMSTELLAR MATTER
- PRE-MAIN-SEQUENCE STARS
- PLANETARY SYSTEMS
- PROTOPLANETARY DISKS
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