Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-03-28
Astronomy and Astrophysics
Astrophysics
4 pages, 3 figures
Scientific paper
10.1051/0004-6361:20066969
We aim to study the structure of the nebula around the post-AGB, binary star 89 Her. The presence of a rotating disk around this star had been proposed but not been yet confirmed by observations. We present high-resolution PdBI maps of CO J=2-1 and 1-0. Properties of the nebula are directly derived from the data and model fitting. We also present N-band interferometric data on the extent of the hot dust emission, obtained with the VLTI. Two nebular components are found: (a) an extended hour-glass-like structure, with expansion velocities of about 7 km/s and a total mass ~ 3 10$^{-3}$ Mo, and (b) an unresolved very compact component, smaller than ~ 0.4" and with a low total velocity dispersion of ~ 5 km/s. We cannot determine the velocity field in the compact component, but we argue that it can hardly be in expansion, since his would require too recent and too sudden an ejection of mass. On the other hand, assuming that this component is a keplerian disk, we derive disk properties that are compatible with expectations for such a structure; in particular, the size of the rotating gas disk should be very similar to the extent of the hot dust component from our VLTI data. Assuming that the equator of the extended nebula coincides with the binary orbital plane, we provide new results on the companion star mass and orbit.
Alcolea Javier
Bujarrabal Valentin
Castro-Carrizo Arancha
Deroo Pieter
Neri Roberto.
No associations
LandOfFree
The nebula around the post-AGB star 89 Her does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The nebula around the post-AGB star 89 Her, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The nebula around the post-AGB star 89 Her will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-271985