2003/10/23 by P. J. Diamond, A. J. Kemball · 8 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/379347
published as Astrophys.J. 599 (2003) 1372-1382 · Mpeg movie can be obtained from http://www.jb.man.ac.uk/~pdiamond/txcam_movie.mpeg
arxiv created 2003/10/23 · openalex publication_date 2003/12/20 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
We describe an observing campaign using the Very Long Baseline Array (VLBA) to monitor the time evolution of the v = 1, J = 1-0 SiO maser emission toward the Mira variable TX Cam. The data reported here cover the period 1997 May 24 to 1999 February 19, during which the SiO maser emission was imaged at approximately biweekly intervals. The result is an animated movie at an angular resolution of ~500 μas, over a full pulsation period, of the gas motions in the near circumstellar environment of this star, as traced by the SiO maser emission. This paper serves to release the movie and is the first in a series concerning the scientific results from this observing campaign. In this paper, we discuss the global proper motion of the SiO maser emission as a function of pulsation phase. We measure a dominant expansion mode between optical phases ϕ ~ 0.7 and 1.5 confirming ballistic deceleration and compare this to predictions from existing pulsation models for late-type, evolved stars. Local infall and outflow motions are superposed on the dominant expansion mode, and nonradial local gas motions are also evident for individual SiO maser components. The overall morphology and evolution of the SiO emission deviates significantly from spherical symmetry, with important implications for models of pulsation kinematics in the near-circumstellar environments of Mira variables.