Proceedings of the International Astronomical Union

Table of Contents - January 2012 - Volume 8, Symposium S287 (Cosmic Masers - from OH to H0)  

Contributed Papers

Annual Parallax Measurements of an Infrared Dark Cloud MSXDC G034.43+00.24

Tomoharu Kurayamaa1

a1 Department of Physics and Astronomy, Graduate School of Science and Engineering, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065, Japan email: kurayama@sci.kagoshima-u.ac.jp

Abstract

We have measured the annual parallax of the H2O maser associated with an infrared dark cloud, MSXDC G034.43+00.24, with VERA. The parallax is 0.643 ± 0.049 mas, corresponding to a distance of 1.56+0.12 −0.11 kpc. This value is less than half of the previous kinematic distance of 3.7 kpc. We revised the core-mass estimates of MSXDC G034.43+00.24 from the previous estimations of 1000M ⊙ to hundreds of M ⊙. The spectral type is still consistent with that of the massive star.

Keywords

  • astrometry;
  • IRDC;
  • star formation