On some Stars Probably Having Extended Atmospheres or Gas-Dust Shells, or Circumstellar Disk-like Structures, According to the Results of High-Speed Photometry of Their Lunar Occultationsстатья
Дата последнего поиска статьи во внешних источниках: 1 февраля 2021 г.
Аннотация:When the edge of the dark part of the lunar disk covers (occults) one or another star, at the movement of the Moon relatively stars in the sky, a diffraction effects arise, and as a result one can record a diffraction curve of stellar occultation. A typical duration of passing of the first Fresnel zone over line of sight of the observer for the light source with a very small angular diameter (of the order of a few milliarcseconds (mas)) is of the order of 20 milliseconds (ms), therefore for a sufficiently detailed registration of changes of the light flux in the diffraction pattern it is necessary to record them with a time resolution of the order of 1 ms. For that one should have some modern photometric recorder which allows us to record light flux from the investigated star with the mentioned time resolution. If the diffraction curve of the lunar occultation of a star is recorded then it is possible to do it’s analysis in order to distinguish it from the diffraction curve corresponding to the occultation of a point-like source, and thus to determine directly the angular size of the star under study. During more than 35 years a several tens of occultation diffraction curves of various stars have been recorded with a time resolution of 1 ms in the Observatories of Sternberg Astronomical Institute of M.V.Lomonosov Moscow State University. When processing the data obtained the angular sizes of some stars have been determined directly. Among the stars studied by the method described, the author discovered a number of objects that, in all probability, have a complex structure and include either an extended stellar atmosphere, or a gas-dust envelope, or a circumstellar disk-like structure. Some examples of such results are presented.