SUPERFAST LINE PROFILE VARIATIONS IN STELLAR SPECTRA

Abstract

The regular line profiles variations (LPVs) with periods ranging from a few  hours to days in spectra of stars are well investigated. At the same time the LPVs at minute time scale are badly known. In order to study the spectral variability on such short timescales, we launched Large Project to search for the superfast line profile variations (sfLPVs) in spectra of bright stars. By the end of 2022 year we have obtained over 20000 spectra of selected OBAFGKM stars at the 6-m and 1-m telescopes of the Special
Astrophysical Observatory (Northern Caucasus, Russia) and at the 1.25-m telescope of Crimean Astronomical Station of the Sternberg Astronomical Institute (Moscow State University, Russia). Both regular LPVs with periods from 2 to 140 minutes and non-regular LPVs with amplitudes of 1-3% of the continuum level were detected for all studied stars. Such short-term spectral
variability was not studied systematically in the past, while it can be crucial for the future theoretical understanding of the stellar physics and for modeling the stellar evolution. We plan to use additional telescopes for spectral observations with an ultra-high temporal resolution and in particular the Shamakhy Astrophysical Observatory (SHAO) 2-m telescope. In future we are also going to study the sfLPVs for bright stars at the pre-main stage of stellar evolution.