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SUMMARY:Boris Safonov (Sternberg Astronomical Institute\, MSU\, Moscow)
DTSTART:20210218T143000Z
DTEND:20210218T153000Z
DTSTAMP:20260423T021230Z
UID:CENTRA/31
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/CENTRA/31/">
 Differential Speckle Polarimetry of evolved stars\, including Betelgeuse</
 a>\nby Boris Safonov (Sternberg Astronomical Institute\, MSU\, Moscow) as 
 part of CENTRA Seminar\n\n\nAbstract\nDifferential speckle polarimetry (DS
 P) is a method aimed at study of distribution of polarized flux in astroph
 ysical objects at diffraction limited resolution. Using DSP at SAI 2.5 m\,
  telescope we detected in visual wavelength range dusty envelopes with an 
 angular size of 0.05-0.15 arcsec around a number of evolved stars\, e.g. m
 u Cep (Safonov et al\, MNRAS\, 484\, 5129). Quite frequently these envelop
 es exhibit variability of morphology associated with the photometric varia
 bility. For example\, in the circumstellar envelope of semiregular variabl
 e star V CVn we detected two regions changing their brightness with the sa
 me period as the star\, but with significant phase delays\, up to a half o
 f the period. On the basis of these data we suggest that the pulsations of
  V CVn are non-radial (Safonov et al\, AstL\, 45\, 453). In case of Betelg
 euse we confirm that the brightness minimum of 2019-2020 is due to the for
 mation of a dust cloud at the line of sight. Apart from this\, during reco
 very from minimum the amount of scattering dust in the envelope increased 
 (arXiv:2005.05215). DSP provides new interesting opportunities to study th
 e mass loss of evolved stars.\n
LOCATION:https://researchseminars.org/talk/CENTRA/31/
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