Short- and long-term variations of the high mass accretion rate classical T Tauri star DR Tau
Year: 2025
Type: article
Abstract: Context. Classical T Tauri stars are newly formed, low-mass stars, which may display both periodic and random variations in their brightness. These systems are surrounded by a circumstellar disk, from which material falls onto the stellar surface. The interaction between the star and the circumstellar disk is time dependent, leading to short- or long-term physical changes in the physical environment, and hence variability of the system. Aims. DR Tau is a highly variable young star. By compiling a large dataset with high-cadence photometric, and high-resolution spectroscopic observations, we aim to examine the short- and long-term variability of the system, and identify the underlying physical mechanisms. Methods. We combined multifilter ground-based optical, near-infrared, and space-based mid-infrared (Spitzer Space Telescope) monitoring observations from 2009, 2017, and 2021 with high-cadence optical Kepler K2 and TESS light curves. We complemented our photometric dataset with spectropolarimetric monitoring observations obtained with the CFHT/ESPaDOnS instrument in 2016, which provided high-resolution data at optical wavelengths. Results. Our results reveal that DR Tau exhibits stochastic photometric variability not only on daily, but also on hourly timescales, with a peak-to-peak amplitude of 1.4 mag probably originating from accretion related variations. Our ground-based multifilter photometry shows that the shape of the light curves are similar at all wavelengths, although the amplitude of the variability decreases with increasing wavelength. This trend toward the infrared wavelengths suggests that part of the disk may be optically thick and invariable. In addition to this, the high-cadence Kepler and TESS data allowed us to carry out a detailed period analysis. The spectroscopic analysis showed that the Hα line presents the most complex line profile with several components, but the significance of the components changes over time. This suggests the presence and variation of both accretion flow and wind. Broad and narrow components can be clearly distinguished in the He I and the Ca II lines, which suggests a contribution from both the accretion flow and the post-shock region. The CFHT/ESPaDOnS data suggest that the strength of the longitudinal magnetic field varies between 400 and 1800 G. Conclusions. DR Tau exhibits a high level of photometric and spectroscopic variability on both short and long timescales, which is caused by the combination of accretion, wind, stellar activity, and obscuration by circumstellar matter. Furthermore, the significance of the physical mechanisms that cause the observed variability changes over time.
Source: Astronomy and Astrophysics
Authors: Gabriella Zsidi, Ágnes Kóspál, Péter Ábrahám, Evelyne Alecian, Silvia H. P. Alencar, Jérôme Bouvier, Gaitee A. J. Hussain, Carlo F. Manara, Michal Siwak, Róbert Szabó, Zsófia Bora, Borbála Cseh, Csilla Kalup, Csaba Kiss, Levente Kriskovics, Mária Kun, András Pál, Ádám Sódor, Krisztián Sárneczky, Róbert Szakáts, Krisztián Vida, József Vinkó, Zófia M. Szabó
Institutions: University of Leeds, University of Hertfordshire, Konkoly Observatory, HUN-REN Research Centre for Astronomy and Earth Sciences, Eötvös Loránd University, Max Planck Institute for Astronomy, University of Vienna, Centre National de la Recherche Scientifique, Institut de Planétologie et d'Astrophysique de Grenoble, Université Grenoble Alpes, Universidade Federal de Minas Gerais, European Space Research and Technology Centre, European Southern Observatory, Uniwersytet Komisji Edukacji Narodowej w Krakowie, University of St Andrews, Scottish Universities Physics Alliance, Max Planck Institute for Radio Astronomy
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
Funders: International Max Planck Research School for Environmental, Cellular and Molecular Microbiology, Leverhulme Trust, University of St Andrews, European Commission, Hungarian Scientific Research Fund, Magyar Tudományos Akadémia, Eötvös Loránd Tudományegyetem, Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, International Max Planck Research School for Advanced Methods in Process and Systems Engineering, European Research Council, Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, National Research, Development and Innovation Office
Awards: G104587016, G1276606689, G134384773, G1594289875, G1633738584, G1670443309, G1794428649, G1943662793, G2190636616, G2275909756, G2582899647, G2720707006, G2887042175, G298428782, G3516063596, G3544690935, G3743470659, G3919879982, G434337789, G4386331455, G4554118389, G4660793865, G4796318435, G4901146333, G4927423465, G5171098215, G5483924367, G5519330468, G5788995006, G6155711494, G6275013681, G6750004076, G7339330145, G7397826953, G7489253783, G7497467928, G7682328652, G7694217703, G7763511631, G7781198223, G7917496354, G804656356, G993751968
OpenAlex ID: W4411202376