Annual Parallax Distance and Kinematical Property of H2O Masers in IRAS 19312+1950

作者：Imai Hiroshi^*; Tafoya Daniel; Honma Mareki; Hirota Tomoya; Miyaji Takeshi

来源：Publications of the Astronomical Society of Japan, 2011, 63(1): 81-87.

• masers
• stars: AGB and post-AGB
• stars: individual (IRAS 19312+1950)

We report on results of astrometric observations of H2O masers in the pre-planetary nebula candidate source IRAS 19312+1950 with the VLBI Exploration of Radio Astrometry (VERA), yielding an annual parallax, pi = 263 +/- 47 mu as, and a secular motion, (mu(alpha), mu(delta)) = (-2.61 +/- 0.47, -6.73 +/- 0.14) [mas yr(-1)], for IRAS 19312+1950. We then derived a heliocentric distance of D = 3.80(-0.58)(+0.83) kpc, a location in the Galaxy (R, z) = (7.07 +/- 0.12 kpc, 28 +/- 3 pc), and a three-dimensional velocity vector (V-R, V-theta, V-z) = (33 +/- 28, 214 +/- 4, -14 +/- 8) [km s(-1)] in galactic cylindrical coordinates. Based on these parameters, we discuss the intrinsic properties of IRAS 19312+1950. We estimated the mass of the central star to be similar to 8 M-circle dot and the deviation of the source motion from the circular galactic rotation to be similar to 40 km s(-1). These are consistent with this source being an intermediate-mass late AGB or early post-AGB star.

• 出版日期2011
• 单位中国科学院国家天文台