Astrometry of OH/IR Stars Using 1612 MHz Hydroxyl Masers. I. Annual Parallaxes of WX Psc and OH138.0+7.2
Astrometry of OH/IR Stars Using 1612 MHz Hydroxyl Masers. I. Annual Parallaxes of WX Psc and OH138.0+7.2
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DOI：
10.3847/1538-3881/153/3/119
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发表时间：
2017-01
期刊：
影响因子：
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通讯作者：
G. Orosz;H. Imai;R. Dodson;M. Rioja;S. Frey;R. Burns;S. Etoka;A. Nakagawa;H. Nakanishi
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文献类型：
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作者：
G. Orosz;H. Imai;R. Dodson;M. Rioja;S. Frey;R. Burns;S. Etoka;A. Nakagawa;H. Nakanishi
本文报道了用NRAO甚长基线阵在束内相位参考定标测量1612 MHz氢氧脉泽在两颗渐近巨星分支星WX Psc和OH 138.0+7.2周围的三角视差。我们得到WX Psc视差的3σ上限≤5.3 mas，对应的下限距离估计为190 pc。OH 138.0+7.2的视差为0.52 ± 0.09 mas（±18%），对应的距离为，使其成为第一个低于1毫角秒的羟基脉泽视差。本文还介绍了一种新的误差分析方法，用以检测天体测量中的系统误差。最后，我们比较了我们的三角距离公布的相位滞后距离对这些恒星，并找到一个很好的协议之间的两种方法。
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 3σ 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 , 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.