|
|
|
____________________
|
|
|
|
|
Wednesday 21 April at 2pm @ JAC
Huib Jan van Langevelde - JIVE
"Astrometry of circumstellar OH masers"
ABSTRACT: "The bright, compact masers in circumstellar shells can be observed with
astrometric VLBI in order to accurately determine the position of the
star, as well as its motion, including the parallax. Results will be
presented on OH masers from 4 Mira stars monitored for 2 - 8 years with
the VLBA. The data show that in some stars the VLBI detection is
dominated by blue-shifted emission that is associated with the stellar
image amplified by the maser shell in front of the star. In other cases
the maser is not directly tied to the stellar position, but still
persistent enough to measure proper motion and parallax. The
possibility to use H2O and SiO masers for this purpose will be discussed."
|
|
