Open this publication in new window or tab >>Show others...
2025 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 694, article id A257Article in journal (Refereed) Published
Abstract [en]
Context. UX Orionis stars are the most active young stars; they undergo sporadic fadings of 2–4 magnitudes in the V-band, due to variable circumstellar extinction caused by a nearly edge-on star–disc system. The long-lasting monitoring of a number of stars of this type with the Nordic Optical Telescope from 2019 to 2024 has given a rich collection of material of high-resolution (R ∼ 25 000) spectra obtained during different brightness states of the stars. In this paper, we present the results of observations for UX Ori itself. Until now only one spectrum of high resolution had been obtained for this star during brightness minimum, making it difficult to do a comprehensive analysis.
Aims. Our aim is to analyse how different spectral lines change during such irregular fading events, when the star is going in and out of eclipses, obscured by dust along the line of sight.
Methods. For this purpose we provide a comparative analysis of the profiles and equivalent widths of the spectral lines belonging to the different atoms and ions. In addition we compare the results for UX Ori with those made for another target in our sample: RR Tau.
Results. Common features of variability are revealed: (1) a strengthening of the Hα line relatively to the continuum during eclipses; (2) the appearance of additional emission on the frequencies of photospheric lines (e.g. FeII, CaII, SiII). The different behaviour of the spectral lines during fading found for UX Ori and RR Tau may be caused by two effects: a different contribution of the scattered light to the stellar flux during eclipses or a less intense disc wind of UX Ori.
Place, publisher, year, edition, pages
EDP Sciences, 2025
Keywords
accretion, accretion disks – techniques: spectroscopic – stars, individual, UX Ori – stars, individual, RR Tau – stars, variables, T Tauri, Herbig Ae/Be – stars, winds, outflows
National Category
Astronomy, Astrophysics and Cosmology
Research subject
Applied Physics
Identifiers
urn:nbn:se:ltu:diva-111794 (URN)10.1051/0004-6361/202451818 (DOI)2-s2.0-85218413089 (Scopus ID)
Note
Godkänd;2025;Nivå 0;2025-04-22 (u5);
Fulltext license: CC BY
2025-03-102025-03-102025-04-23Bibliographically approved