2024/01/16 by М. А. Бурлак, А. В. Додин, Burlak, M. A. +17
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #Stellar, planetary, and galactic studies
paper · pdf · doi:10.48550/arxiv.2401.08387
openalex publication_date 2024/01/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The results of photometric, polarimetric and spectroscopic observations of the young star ZZ Tau IRS in the visible and near-infrared bands are presented. Against the continuum of an M spectral type star about 50 emission lines of allowed (HI, HeI, NaI, SII) and forbidden (OI, OII, OIII, NI, NII, SII, CaII, FeII, NiII) transitions were identified. It was found that from the autumn of 2020 to the beginning of 2023, the brightness of the star in the visible region decreased (ΔI ≈ 1.5m), and then began to return to initial level. As the visible brightness of the star declined, its colour indices decreased in the visible region, but increased in the near-IR bands. At light minimum, the degree of polarization in the I band reached ≈ 13%, and the equivalent widths of e.g. the Hα and [SII] 6731 A lines increased to 376 and 79 A, respectively. Arguments are given in favour of ZZ Tau IRS being a UX Ori type star, and its variability being due to eclipses by dust clouds, which are inhomogeneities in the dusty disc wind. Forbidden lines are formed both in the disc wind and in the jet, the axis of which is oriented along PA=61± 3 degrees. The jet mass-loss rate is >5 × 10-10 M_\odot/yr, what is abnormally large for a star with a mass of <0.3 M_\odot. Apparently, the disc wind of ZZ Tau IRS is not axially symmetric, probably due to the azimuthal asymmetry of the protoplanetary disc found earlier from ALMA observations.