Astrometric VLBI Observations of the Galactic LPVs, Miras, and OH/IR stars
Astrometric VLBI Observations of the Galactic LPVs, Miras, and OH/IR stars
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银河 LPV、Miras 和 OH/IR 恒星的天体测量 VLBI 观测
DOI：
10.1017/s1743921317009449
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
keiichi Wada
中科院分区：
文献类型：
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作者：
Akiharu Nakagawa;Tomoharu Kurayama;Gabor Orosz;Ross A. Burns;Tomoaki Oyama;Takumi Nagayama;Takashi Miyata;Mamoru Sekido;Junichi Baba;keiichi Wada
介绍了基于天体测量VLBI的银河系LPV研究。我们利用VLBI观测站“VERA”对银河系Miras进行了射电观测和K波段周期光度关系（PLR）标定。由于PLR提供了一个距离指标，它的校准对于揭示它们的空间分布至关重要。文中给出了几十个LPV的视差图。对于较长周期的恒星，质量损失很大，恒星被遮蔽，被认为是OH/IR星。我们估计了几十颗OH/IR星的中红外绝对星等，发现它们在11.6 μm的λ处显示出-14等的松散浓度，表明OH/IR星存在PLR。OH/IR星的天体测量也将帮助我们研究非定常螺旋臂，这是从最新的银河系动力学模拟研究中提出的。我们将用VERA在43 GHz对两颗OH/IR星NSV 25875和OH 127.8 +0.0进行天体测量VLBI观测。
Studies of Galactic LPVs based on astrometric VLBI are presented. We use a VLBI array, “VERA”, to measure parallaxes and calibrate the K-band period luminosity relation (PLR) of the Galactic Miras. Since the PLR offers a distance indicator, its calibration is crucial to reveal their spatial distribution. Parallaxes of dozens of LPVs are presented. For the longer period stars, the mass-loss is high and the stars are obscured and recognized as OH/IR stars. We estimated mid-infrared absolute magnitudes of dozens of OH/IR stars and found that they show a loose concentration around −14 mag at λ of 11.6 μm, indicating an existence of PLR for OH/IR stars. Astrometry of OH/IR stars will also help us to study non-steady spiral arms as proposed from the latest simulation study of the galactic dynamics. We will start astrometric VLBI observation of two OH/IR stars NSV25875 and OH127.8+0.0 at 43 GHz with VERA.