TWINKLING STARS The disappearing SiO masers of W Aql
Conference contribution, 2012

W Aql is a binary S-type AGB star showing SiO maser emission. The dust distribution around the star is asymmetric, possibly indicating gravitational interaction between the binary pair. There are indications that the gas distribution also exhibits asymmetries. To investigate the source of the circumstellar structures, we applied for and were rewarded VLBI time to map the distribution of the SiO masers around this source and to constrain the presence and distribution of a possible magnetic field. Using VERA observations we also aim at measuring an accurate parallax to determine the binary separation, however, from showing peak emission of 21 Jy in June 2010, the SiO(1-0) v=1 line at 43 GHz has now disappeared. We find no correlation with the stellar pulsational period.

stars: mass loss

stars: AGB and post-AGB

masers

Author

S. Ramstedt

Argelander-Institut für Astronomie

Wouter Vlemmings

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

S. Mohamed

South African Astronomical Observatory

Y.K. Choi

Max Planck Institute

Hans Olofsson

Chalmers, Earth and Space Sciences, Onsala Space Observatory

Proceedings of the International Astronomical Union

1743-9213 (ISSN) 1743-9221 (eISSN)

Vol. 8 S287 206 - 261

Subject Categories

Astronomy, Astrophysics and Cosmology

Roots

Basic sciences

Infrastructure

Onsala Space Observatory

DOI

10.1017/S1743921312007107

ISBN

9781107032842

More information

Latest update

9/6/2018 1