VLBI Astrometry of AGB Variables with VERA -- A Semiregular Variable S Crateris --

Akiharu Nakagawa; Miyuki Tsushima; Kazuma Ando; Takeshi Bushimata; Yoon Kyung Choi; Tomoya Hirota; Mareki Honma; Hiroshi Imai; Kenzaburo Iwadate; Takaaki Jike; Seiji Kameno; Osamu Kameya; Ryuichi Kamohara; Yukitoshi Kan-Ya; Noriyuki Kawaguchi; Masachika Kijima; Mi Kyoung Kim; Hideyuki Kobayashi; Seisuke Kuji; Tomoharu Kurayama; Toshihisa Maeda; Seiji Manabe; Kenta Maruyama; Makoto Matsui; Naoko Matsumoto; Takeshi Miyaji; Takumi Nagayama; Kayoko Nakamura; Daisuke Nyu; Chung Sik Oh; Toshihiro Omodaka; Tomoaki Oyama; Nicolas Pradel; Satoshi Sakai; Tetsuo Sasao; Katsuhisa Sato; Mayumi Sato; Katsunori M. Shibata; Hiroshi Suda; Yoshiaki Tamura; Kousuke Ueda; Yuji Ueno; Kazuyoshi Yamashita

doi:10.1093/pasj/60.5.1013

VLBI Astrometry of AGB Variables with VERA -- A Semiregular Variable S Crateris --

Astrophysics 2015-05-13 v1

Authors: Akiharu Nakagawa , Miyuki Tsushima , Kazuma Ando , Takeshi Bushimata , Yoon Kyung Choi , Tomoya Hirota , Mareki Honma , Hiroshi Imai , Kenzaburo Iwadate , Takaaki Jike , Seiji Kameno , Osamu Kameya , Ryuichi Kamohara , Yukitoshi Kan-Ya , Noriyuki Kawaguchi , Masachika Kijima , Mi Kyoung Kim , Hideyuki Kobayashi , Seisuke Kuji , Tomoharu Kurayama , Toshihisa Maeda , Seiji Manabe , Kenta Maruyama , Makoto Matsui , Naoko Matsumoto , Takeshi Miyaji , Takumi Nagayama , Kayoko Nakamura , Daisuke Nyu , Chung Sik Oh , Toshihiro Omodaka , Tomoaki Oyama , Nicolas Pradel , Satoshi Sakai , Tetsuo Sasao , Katsuhisa Sato , Mayumi Sato , Katsunori M. Shibata , Hiroshi Suda , Yoshiaki Tamura , Kousuke Ueda , Yuji Ueno , Kazuyoshi Yamashita

View on arXiv ↗ PDF ↗ DOI ↗

Abstract

We present a distance measurement for the semiregular variable S Crateris (S Crt) based on its annual parallax. With the unique dual beam system of the VLBI Exploration for Radio Astrometry (VERA) telescopes, we measured the absolute proper motion of a water maser spot associated with S Crt, referred to the quasar J1147-0724 located at an angular separation of 1.23 $^{\circ}$ . In observations spanning nearly two years, we have detected the maser spot at the LSR velocity of 34.7 km s $^{-1}$ , for which we measured the annual parallax of 2.33 $\pm$ 0.13 mas corresponding to a distance of 430 $^{+25}_{-23}$ pc. This measurement has an accuracy one order of magnitude better than the parallax measurements of HIPPARCOS. The angular distribution and three-dimensional velocity field of maser spots indicate a bipolar outflow with the flow axis along northeast-southwest direction. Using the distance and photospheric temperature, we estimate the stellar radius of S Crt and compare it with those of Mira variables.

Keywords

VLBI astrometry AGB variables semiregular variable water maser annual parallax distance measurement bipolar outflow

Cite

@article{arxiv.0808.1151,
  title  = {VLBI Astrometry of AGB Variables with VERA -- A Semiregular Variable S Crateris --},
  author = {Akiharu Nakagawa and Miyuki Tsushima and Kazuma Ando and Takeshi Bushimata and Yoon Kyung Choi and Tomoya Hirota and Mareki Honma 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 Hideyuki Kobayashi and Seisuke Kuji and Tomoharu Kurayama and Toshihisa Maeda and Seiji Manabe and Kenta Maruyama and Makoto Matsui and Naoko Matsumoto and Takeshi Miyaji and Takumi Nagayama and Kayoko Nakamura and Daisuke Nyu and Chung Sik Oh and Toshihiro Omodaka and Tomoaki Oyama and Nicolas Pradel and Satoshi Sakai and Tetsuo Sasao and Katsuhisa Sato and Mayumi Sato and Katsunori M. Shibata and Hiroshi Suda and Yoshiaki Tamura and Kousuke Ueda and Yuji Ueno and Kazuyoshi Yamashita},
  journal= {arXiv preprint arXiv:0808.1151},
  year   = {2015}
}

Comments

9 pages, 4 figures, accepted for publication in PASJ (Vol.60, No.5, October 25, VERA special issue)

VLBI Astrometry of AGB Variables with VERA -- A Semiregular Variable S Crateris --

Abstract

Keywords

Cite

Comments

Related papers