Astrometry of OH/IR Stars Using 1612MHz Hydroxyl Masers. I. Annual Parallaxes of WX Psc and OH138.0+7.2 MEConference on Why Galaxies Care About AGB Stars III: A Closer Look in Space and Time, JUL 28-AUG
Artikel i vetenskaplig tidskrift, 2017

We report on the measurement of the trigonometric parallaxes of 1612 MHz hydroxyl masers around two asymptotic giant branch stars, WX. Psc and OH. 138.0+7.2, using the NRAO Very Long Baseline Array with in-beam phase referencing calibration. We obtain a 3s upper limit of. <= 5.3 mas on the parallax of WX. Psc, corresponding to a lower limit distance estimate of. 190 pc. The obtained parallax of OH. 138.0+7.2 is 0.52 +/- 0.09 mas (+/- 18%), corresponding to a distance of 1.9(-0.3)(+0.4)kpc, making this the first hydroxyl maser parallax below one milliarcsecond. We also introduce a new method of error analysis for detecting systematic errors in the astrometry. Finally, we compare our trigonometric distances to published phase-lag distances toward these stars and find a good agreement between the two methods.



proper motions



stars: individual (WX Psc

agb stars


stars: AGB and post-AGB

circumstellar oh masers

vlbi astrometry

OH 138.0+7.2)


Astronomy & Astrophysics



h2o masers


G. Orosz

Kagoshima University

H. Imai

Kagoshima University

R. Dodson

University of Western Australia

M. J. Rioja

Observatorio Astronómico Nacional (OAN)

CSIRO Astronomy and Space Science

University of Western Australia

S. Frey

Magyar Tudomanyos Akademia

R. A. Burns

Joint Institute for VLBI in Europe (JIVE)

Kagoshima University

S. Etoka

Universität Hamburg

A. Nakagawa

Kagoshima University

H. Nakanishi

JAXA Institute of Space and Astronautical Science

SKA Organisation

Kagoshima University

Y. Asaki

National Institutes of Natural Sciences

Atacama Large Millimeter-submillimeter Array (ALMA)

S. R. Goldman

Keele University

Daniel Tafoya Martinez

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

Astronomical Journal

0004-6256 (ISSN) 1538-3881 (eISSN)

Vol. 153 3 119- 119


Astronomi, astrofysik och kosmologi


Grundläggande vetenskaper


Onsala rymdobservatorium



Mer information

Senast uppdaterat