منابع مشابه
Improved VLBI astrometry of OH maser stars
Aims. Accurate distances to evolved stars with high mass loss rates are needed for studies of many of their fundamental properties. However, as these stars are heavily obscured and variable, optical and infrared astrometry is unable to provide enough accuracy. Methods. Astrometry using masers in the circumstellar envelopes can be used to overcome this problem. We have observed the OH masers of ...
متن کاملStars in the age of micro-arc-second astrometry
The understanding and modeling of the structure and evolution of stars is based on statistical physics as well as on hydrodynamics. Today, a precise identification and proper description of the physical processes at work in stellar interiors are still lacking (one key point being that of transport processes) while the comparison of real stars to model predictions, which implies conversions from...
متن کاملAstrometry of the OH masers of 4 Mira stars
The OH main line masers in circumstellar shells were observed with astrometric VLBI in order to accurately determine the position of the star, as well as its motion, including the parallax. Results are presented on 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 imag...
متن کاملAdaptive Optics Photometry and Astrometry of Binary Stars. Ii. a Multiplicity Survey of B Stars
We carried out a search for companions to B stars using the adaptive optics system of the Advanced ElectroOptical System 3.6 m telescope. We observed 70 B stars in the I band, finding 16 companions, 10 of which are newly discovered companions. For each system with a detected companion we give its measured astrometry and differential magnitude. We then put the observation in context of the syste...
متن کاملHigh-precision VLBI astrometry of radio-emitting stars
Multiple-epoch phase-referenced VLBI observations of 11 radio-emitting stars have been conducted as part of an astrometric program to link the Hipparcos optical reference frame to the radio extragalactic reference frame. We present the VLBI positions, proper motions and trigonometric parallaxes from this program in the ICRF (International Celestial Reference Frame). These astrometric parameters...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1971
ISSN: 0252-9211
DOI: 10.1017/s0252921100502541