Multi-epoch imaging polarimetry of the SiO masers in the extended atmosphere of the Mira variable TX Cam

Athol J. Kemball, Philip J. Diamond, Ioannis Gonidakis, Modhurita Mitra, Kijeong Yim, Kuo Chuan Pan, Hsin Fang Chiang

Research output: Contribution to journalArticlepeer-review


We present a time series of synoptic images of the linearly polarized ν = 1, J = 1-0 SiO maser emission toward the Mira variable, TX Cam. These data comprise 43 individual epochs at an approximate biweekly sampling over an optical pulsation phase range of φ = 0.68 to φ = 1.82. The images have an angular resolution of ∼500 μas and were obtained using the Very Long Baseline Array (VLBA), operating in the 43 GHz band in spectral-line, polarization mode. We have previously published the total intensity time series for this pulsation phase range; this paper serves to present the linearly polarized image sequence and an associated animation representing the evolution of the linear polarization morphology over time. We find a predominantly tangential polarization morphology, a high degree of persistence in linear polarization properties over individual component lifetimes, and stronger linear polarization in the inner projected shell than at larger projected shell radii. We present an initial polarization proper motion analysis examining the possible dynamical influence of magnetic fields in component motions in the extended atmospheres of late-type, evolved stars.

Original languageEnglish (US)
Pages (from-to)1721-1739
Number of pages19
JournalAstrophysical Journal
Issue number2
StatePublished - Jun 20 2009


  • Masers
  • Polarization
  • Stars: individual (TX Cam)
  • Stars: magnetic fields

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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