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Astrometry of H2O Masers in Nearby Star-Forming Regions with VERA III. IRAS22198+6336 in Lynds1204G

2008; Oxford University Press; Volume: 60; Issue: 5 Linguagem: Inglês

10.1093/pasj/60.5.961

2053-051X

Tomoya Hirota, Kazuma Ando, Takeshi Bushimata, Yoon Kyung Choi, 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, Seiji Manabe, Makoto Matsui, Naoko Matsumoto, Takeshi Miyaji, Atsushi Miyazaki, Takumi Nagayama, Akiharu Nakagawa, Daichi Namikawa, Daisuke Nyu, Chung Sik Oh, Toshihiro Omodaka, Tomoaki Oyama, Satoshi Sakai, Tetsuo Sasao, Katsuhisa Sato, Mayumi Sato, Katsunori M. Shibata, Yoshiaki Tamura, Kosuke Ueda, Kazuyoshi Yamashita,

Galaxies: Formation, Evolution, Phenomena

Abstract We present results of multi-epoch VLBI observations with VERA (VLBI Exploration of Radio Astrometry) of the 22GHz H$_{2}$O masers associated with a young stellar object (YSO) IRAS22198$+$6336 in a dark cloud, L1204G. Based on phase-referencing VLBI astrometry, we derived an annual parallax of IRAS22198$+$6336 to be 1.309$\pm$0.047mas, corresponding to the distance of 764$\pm$27pc from the Sun. Although the most principal error source of our astrometry is attributed to the internal structure of the maser spots, we successfully reduced the errors in the derived annual parallax by employing position measurements for all of the 26 detected maser spots. Based on this result, we reanalyzed the spectral energy distribution of IRAS22198$+$6336 and found that the bolometric luminosity and total mass of IRAS22198$+$6336 are 450$L_{\odot}$ and 7$M_{\odot}$, respectively. These values are consistent with an intermediate-mass YSO deeply embedded in the dense dust core, which has been proposed to be an intermediate-mass counterpart of a low-mass Class 0 source. In addition, we obtained absolute proper motions of the H$_{2}$O masers for the most blue-shifted components. We propose that the collimated jets aligned along the east-west direction are the most plausible explanation for the origin of the detected maser features.