Variable Asymmetry of the Circumstellar Envelope in IK Tauri Traced by SiO Maser Emission

Details Variable Asymmetry of the Circumstellar Envelope in IK Tauri Traced by SiO Maser Emission Variable Asymmetry of the Circumstellar Envelope in IK Tauri Traced by SiO Maser Emission

Oct 2008

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008pasj...60.1039m&link_type=abstract

Publications of the Astronomical Society of Japan, Vol.60, No.5, pp.1039--1050

Astronomy and Astrophysics

Astronomy

7

Circumstellar Matter, Masers, Stars: Agb And Post-Agb, Stars: Individual (Ik Tauri)

Scientific paper

We observed the SiO (v = 1 and v = 2, J = 1--0) maser emissions toward the Mira variable IK Tauri (IK Tau, NML Tau, IRC+10050) over nine epochs from 2003 November to 2005 April using the VLBI Exploration of Radio Astrometry (VERA) telescope array. We found that the SiO maser distributions around IK Tau are highly variable, depending on the stellar pulsation phase. The velocity structures were complex and also time-variable, and are inconsistent with a simply rotating shell that was suggested by previous observations. Based on fittings of the SiO maser distributions to elliptical ring models, we found that the ring size seems to vary in correlation with the pulsation phase, as previously found for TX Cam. Comparisons of the v = 1 and v = 2 maser distributions reveal that 42--50% of the maser pairs have a positional offset less than 0.5mas, suggesting that the maser pumping in these spots is likely to be dominated by line overlapping or collisional pumping, rather than pure radiative pumping. In order to model the velocity structure of the spoke-like features observed in IK Tau, we propose a ballistic-orbit model, in which a gas clump ejected from the stellar surface moves radially outward with a gravitational deceleration, and argue that the stellar mass can be deduced from that model.

Affiliated with

Also associated with

No associations

Rating

Variable Asymmetry of the Circumstellar Envelope in IK Tauri Traced by SiO Maser Emission does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Variable Asymmetry of the Circumstellar Envelope in IK Tauri Traced by SiO Maser Emission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Variable Asymmetry of the Circumstellar Envelope in IK Tauri Traced by SiO Maser Emission will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-865035