Korean VLBI Network (KVN)



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01/23/2015   01/30/2015   02/13/2015   02/27/2015   03/20/2015   04/10/2015   05/08/2015   05/15/2015   05/22/2015   05/29/2015   06/05/2015   06/12/2015   07/03/2015   07/24/2015   07/31/2015   08/07/2015   08/28/2015   09/04/2015   09/18/2015   09/25/2015   10/02/2015   10/30/2015   11/06/2015   11/27/2015  

Date
05/08/2015
Speaker
Dr. Yoon Kyung Choi (Radio Research Group)
Title
Distance to the Protoplanetary Nebula OH 231.8+4.2
Abstract

We present results of the Very Long Baseline Array (VLBA) observations of 22 GHz H2O and 43 GHz SiO masers toward the protoplanetary nebula OH 231.8+4.2. Our observations were carried out at 4 epochs over 1 year in order to measure an accurate distance and proper motions of OH 231.8+4.2. Based on astrometric monitoring for 1 year, we detected an annual parallax of OH 231.8+4.2 to be 0.65 \pm 0.01 mas, corresponding to a distance of 1.54 (+0.02/-0.01) kpc.

The measured proper motion of OH 231.8+4.2 is mu_x = -4.35 \pm 0.02 mas/yr eastward and mu_y = 0.71 \pm 0.59 mas/yr northward.

The spatial distribution of the H 2 O masers is consistent with that found in previous studies.

After removing the average proper motion of 1.4 mas/yr, corresponding to 10 km/s, the internal motions of the H2O maser spots indicate a bipolar outflow.


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