TY - JOUR

T1 - Density streams in the disc winds of Classical T Tauri stars

AU - Petrov, P.

AU - Grankin, K.

AU - Babina, E.

AU - Artemenko, S.

AU - Romanova, M.

AU - Gorda, S.

AU - Djupvik, A.

AU - Gameiro, J. F.

N1 - The Crimean observations in 2019–2020 by S. Artemenko, E. Babina, and P. Petrov were supported by a grant from the Russian Science Foundation 19-72-10063. The work of SYG was partially supported by the Ministry of Science and Higher Education of Russia, topic no. FEUZ-2023-0019. MMR was supported in part by NSF grant AST-2009820. JFG was supported by fundação para a Ciência e Tecnologia (FCT) through the research grants UIDB/04434/2020 and UIDP/04434/2020.

PY - 2023

Y1 - 2023

N2 - Spectral and photometric variability of the Classical T Tauri stars RY Tau and SU Aur from 2013 to 2022 is analysed. We find that in SU Aur the H alpha line's flux at radial velocity RV = -50 +/- 7 km s(-1) varies with a period P = 255 +/- 5 d. A similar effect previously discovered in RY Tau is confirmed with these new data: P = 21.6 d at RV = -95 +/- 5 km s. In both stars, the radial velocity of these variations, the period, and the mass of the star turn out to be related by Kepler's law, suggesting structural features on the disc plane orbiting at radii of 0.2 au in RY Tau and 0.9 au in SU Aur, respectively. Both stars have a large inclination of the accretion disc to the line of sight - so that the line of sight passes through the region of the disc wind. We propose there is an azimuthal asymmetry in the disc wind, presumably in the form of 'density streams,' caused by substructures of the accretion disc surface. These streams cannot dissipate until they go beyond the Alfven surface in the disc's magnetic field. These findings open up the possibility to learn about the structure of the inner accretion disc of CTTS on scales less than 1 au and to reveal the orbital distances related to the planet's formation.

AB - Spectral and photometric variability of the Classical T Tauri stars RY Tau and SU Aur from 2013 to 2022 is analysed. We find that in SU Aur the H alpha line's flux at radial velocity RV = -50 +/- 7 km s(-1) varies with a period P = 255 +/- 5 d. A similar effect previously discovered in RY Tau is confirmed with these new data: P = 21.6 d at RV = -95 +/- 5 km s. In both stars, the radial velocity of these variations, the period, and the mass of the star turn out to be related by Kepler's law, suggesting structural features on the disc plane orbiting at radii of 0.2 au in RY Tau and 0.9 au in SU Aur, respectively. Both stars have a large inclination of the accretion disc to the line of sight - so that the line of sight passes through the region of the disc wind. We propose there is an azimuthal asymmetry in the disc wind, presumably in the form of 'density streams,' caused by substructures of the accretion disc surface. These streams cannot dissipate until they go beyond the Alfven surface in the disc's magnetic field. These findings open up the possibility to learn about the structure of the inner accretion disc of CTTS on scales less than 1 au and to reveal the orbital distances related to the planet's formation.

UR - https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=tsmetrics&SrcApp=tsm_test&DestApp=WOS_CPL&DestLinkType=FullRecord&KeyUT=001046003200003

UR - http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=85168759862

U2 - 10.1093/mnras/stad2252

DO - 10.1093/mnras/stad2252

M3 - Article

VL - 524

SP - 5944

EP - 5953

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 4

ER -