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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

G. Orosz ; H. Imai ; R. Dodson ; M. J. Rioja ; S. Frey ; R. A. Burns ; S. Etoka ; A. Nakagawa ; H. Nakanishi ; Y. Asaki ; S. R. Goldman ; Daniel Tafoya Martinez (Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium ; Institutionen för rymd- och geovetenskap, Radioastronomi och astrofysik)
Astronomical Journal (0004-6256). Vol. 153 (2017), 3, p. 119.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: astrometry, masers, stars: AGB and post-AGB, stars: individual (WX Psc, OH 138.0+7.2), techniques:, circumstellar oh masers, vlbi astrometry, proper motions, software, correlator, h2o masers, agb stars, distance, pulsars, vera, Astronomy & Astrophysics



Denna post skapades 2017-05-05.
CPL Pubid: 249135

 

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Institutioner (Chalmers)

Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium (2010-2017)
Institutionen för rymd- och geovetenskap, Radioastronomi och astrofysik (2010-2017)

Ämnesområden

Astronomi, astrofysik och kosmologi
Astronomi

Chalmers infrastruktur

Onsala rymdobservatorium