Proceedings of the International Astronomical Union

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

Contributed Papers

Trigonometric Parallax of the Protoplanetary Nebula OH 231.8+4.2

Y. K. Choia1 c1, A. Brunthalera1, K. M. Mentena1 and M. J. Reida2

a1 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany

a2 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

Abstract

We report a trigonometric parallax measurement for the H2O masers around the protoplanetary nebula OH 231.8+4.2 carried out with the Very Long Baseline Array (VLBA). Based on astrometric monitoring for 1 year, we measured a parallax of 0.65 ± 0.01 mas, corresponding to a distance of 1.54 +0.02 −0.01 kpc. The spatial distribution of H2O masers is consistent with that found in the previous studies. After removing the average proper motion of 1.4 mas yr−1, corresponding to 10 km s−1, the internal motions of the H2O maser spots indicate a bipolar outflow.

Keywords

  • masers;
  • astrometry;
  • stars: late-type;
  • stars: distances;
  • stars: individual (OH 231.8+4.2)

Correspondence:

c1 email: ykchoi@mpifr-bonn.mpg.de