Tatsuya Kamezaki, Akiharu Nakagawa, Toshihiro Omodaka, Tomoharu Kurayama, Hiroshi Imai, Daniel Tafoya, Makoto Matsui, Yoshiro Nishida, Takumi Nagayama, Mareki Honma, Hideyuki Kobayashi, Takeshi Miyaji, Mine Takeuti
We present distance measurement of the semiregular variable RX Bootis (RX
Boo) with its annual parallax. Using the unique dual-beam system of the VLBI
Exploration of Radio Astrometry (VERA) telescope, we conducted astrometric
observations of a water maser spot accompanying RX Boo referred to the quasar
J1419+2706 separated by 1.69 degrees from RX Boo. We have measured the annual
parallax of RX Boo to be 7.31 +/- 0.50 mas, corresponding to a distance of 136
+10/-9 pc, from the one-year monitoring observation data of one maser spot at
VLSR = 3.2 km/s. The distance itself is consistent with the one obtained with
Hipparcos. The distance uncertainty is reduced by a factor of two, allowing us
to determine the stellar properties more accurately. Using our distance, we
discuss the location of RX Boo in various sequences of Period-Luminosity (PL)
relations. We found RX Boo is located in the Mira sequence of PL relation. In
addition, we calculated the radius of photosphere and the mass limitation of RX
Boo and discussed its evolutionary status.
View original:
http://arxiv.org/abs/1201.3721
No comments:
Post a Comment