A Bipolar Outflow of the M-Type Giant IRC-10414 Traced by H2O Maser Emission

作者：Maeda Toshihisa^*; Imai Hiroshi; Omodaka Toshihiro; Kobayashi Hideyuki; Shibata Katsunori M; Bushimata Takeshi; Choi Yoon Kyung; Hirota Tomoya; Honma Mareki; Horiai Koji; Inomata Noritomo; Iwadate Kenzaburo; Jike Takaaki; Kameno Seiji; Kameya Osamu; Kamohara Ryuichi; Kan ya Yukitoshi; Kawaguchi Noriyuki; Kuji Seisuke; Kurayama Tomoharu; Manabe Seiji; Miyaji Takeshi; Nagayama Takumi; Nakagawa Akiharu; Nakashima Kouichiro; Oh Chung Sik; Oyama Tomoaki; Sakai Satoshi

来源：Publications of the Astronomical Society of Japan, 2008, 60(5): 1057-1067.

• masers
• stars: AGB and post-AGB
• stars: individual (IRC-10414)
• stars: late-type

We report on results of five-epoch VLBI observations of H2O maser emission in the M-type star IRC -10414, carried out with the VLBI Exploration of Radio Astrometry (VERA). The maser distribution extends overall area of 70 mas x 260 mas and exhibits a bipolar structure. The relative proper motions of 17 maser features were measured during the monitoring observations spanning nine months. The distance to IRC-10414 was re-estimated on the basis of the statistical treatment of parallax and the model-fitting method, yielding D = 3.1 +/- 0.4 kpc and D 2.0 +/- 0.2 kpc, respectively. The estimated distance, D = 2-3 kpc, is much larger than that previously adopted. The stellar luminosity of IRC -10414 is also re-estimated to be L-* similar to 9 x 10(4) (D/2 kpc)(2) L-circle dot, much brighter by a factor of 10-20 than previously adopted (L-* similar to 10000 L-circle dot). The maser motions exhibit not only a spherically expanding flow with a velocity of similar to 10 (D/2 kpc) km s(-1), but also a faster bipolar outflow with a major axis in the north-south direction and at a small inclination angle with respect to the celestial sphere. These characteristics of the star and the circumstellar envelope seen in IRC-10414 are very similar to those in some supergiants exhibiting bipolar stellar mass loss.

• 出版日期2008
• 单位中国科学院国家天文台