Issue |
A&A
Volume 385, Number 1, April I 2002
|
|
---|---|---|
Page(s) | L1 - L4 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20020233 | |
Published online | 15 April 2002 |
Letter to the Editor
Submilliarcsecond-resolution mapping of the 43 GHz SiO maser emission in the bipolar post-AGB nebula OH231.8+4.2*
1
Observatorio Astronómico Nacional (OAN), Apdo. 1143, 28800 Alcalá de Henares, Spain e-mail: sanchez,bujarrabal,desmurs,j.alcolea,colomer@oan.es
2
Jet Propulsion Laboratory, California Institute of Technology, MS 183-900, 4800 Oak Grove Dr., Pasadena, CA 91109 e-mail: sanchez@eclipse.jpl.nasa.gov
Corresponding author: C. Sánchez Contreras, sanchez@eclipse.jpl.nasa.gov
Received:
30
November
2001
Accepted:
11
February
2002
We present ~0.3 milliarcsec-resolution maps of
the SiO (,
) maser emission in the bipolar post-AGB
nebula obtained with the Very Long Baseline
Array. These observations have provided for the first time the
structure and kinematics of the close stellar environment in a
proto-Planetary Nebula. Our observations reveal the SiO maser
emission arising in several bright spots of less than
~1013 cm in size forming a structure elongated in the
direction perpendicular to the symmetry axis of the nebula. Such a
distribution is consistent with an equatorial torus with a radius
of ~6 AU around the central star. A complex velocity
gradient is found along the torus, which suggests rotation and
infall of material towards the star. The rotation and infalling
velocities deduced are of the same order and range between
~7 and ~10 km s-1. From our data, we estimate
the mass of the SiO torus and the central star, as well as a
stringent upper limit to the present stellar mass-loss rate.
Key words: masers / stars: AGB and post-AGB / stars: mass-loss / circumstellar matter / stars: individual: OH231.8+4.2 / stars: variables: general
© ESO, 2002
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.