Astrometry of OH/IR stars using 1612 MHz hydroxyl masers. I. Annual parallaxes of WX Psc and OH138.0+7.2

Autor:	Orosz, G., Imai, H., Dodson, R., Rioja, M. J., Frey, S., Burns, R. A., Etoka, S., Nakagawa, A., Nakanishi, H., Asaki, Y., Goldman, S. R., Tafoya, D.
Rok vydání:	2017
Předmět:	Astrophysics - Solar and Stellar Astrophysics Astrophysics - Astrophysics of Galaxies Astrophysics - Instrumentation and Methods for Astrophysics
Druh dokumentu:	Working Paper
DOI:	10.3847/1538-3881/153/3/119
Popis:	We report on the measurement of the trigonometric parallaxes of 1612 MHz hydroxyl masers around two asymptotic giant branch stars, WX Psc and OH138.0+7.2, using the NRAO Very Long Baseline Array with in-beam phase referencing calibration. We obtained a 3-sigma 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 OH138.0+7.2 is 0.52+/-0.09 mas (+/-18%), corresponding to a distance of 1.9(+0.4,-0.3) 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. Comment: Preprint, accepted for publication in The Astronomical Journal (January 17, 2017)
Databáze:	arXiv
Externí odkaz:	http://arxiv.org/abs/1701.05101 Zobrazit plný text záznamu View this record from Arxiv