Distance to VY Canis Majoris with VERA
Abstract
We report astrometric observations of H2O masers around the red supergiant VY Canis Majoris (VY CMa) carried out with VLBI Exploration of Radio Astrometry (VERA). Based on astrometric monitoring for 13 months, we successfully measured a trigonometric parallax of 0.88 +/- 0.08 mas, corresponding to a distance of 1.14 +0.11/-0.09 kpc. This is the most accurate distance to VY CMa and the first one based on an annual parallax measurement. The luminosity of VY CMa has been overestimated due to a previously accepted distance. With our result, we re-estimate the luminosity of VY CMa to be (3 +/- 0.5) x 10^5 L_sun using the bolometric flux integrated over optical and IR wavelengths. This improved luminosity value makes location of VY CMa on the Hertzsprung-Russel (HR) diagram much closer to the theoretically allowable zone (i.e. the left side of the Hayashi track) than previous ones, though uncertainty in the effective temperature of the stellar surface still does not permit us to make a final conclusion.
Cite
@article{arxiv.0808.0641,
title = {Distance to VY Canis Majoris with VERA},
author = {Yoon Kyung Choi and Tomoya Hirota and Mareki Honma and Hideyuki Kobayashi and Takeshi Bushimata and Hiroshi Imai and Kenzaburo Iwadate and Takaaki Jike and Seiji Kameno and Osamu Kameya and Ryuichi Kamohara and Yukitoshi Kan-ya and Noriyuki Kawaguchi and Masachika Kijima and Mi Kyoung Kim and Seisuke Kuji and Tomoharu Kurayama and Seiji Manabe and Kenta Maruyama and Makoto Matsui and Naoko Matsumoto and Takeshi Miyaji and Takumi Nagayama and Akiharu Nakagawa and Kayoko Nakamura and Chung Sik Oh and Toshihiro Omodaka and Tomoaki Oyama and Satoshi Sakai and Tetsuo Sasao and Katsuhisa Sato and Mayumi Sato and Katsunori M. Shibata and Yoshiaki Tamura and Miyuki Thushima and Kazuyoshi Yamashita},
journal= {arXiv preprint arXiv:0808.0641},
year = {2015}
}
Comments
7 pages, 4 figures, accepted for publication in PASJ, VERA special issue