Short- and long-term variations of the high mass accretion rate classical T Tauri star DR Tau

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Main Authors:	Zsidi, Gabriella, Kóspál, Ágnes, Ábrahám, Péter, Alecian, Evelyne, Alencar, Silvia H, Bouvier, Jérôme, Hussain, Gaitee A. J., Manara, Carlo F., Siwak, Michal, Szabó, Róbert, Bora, Zsófia, Cseh, Borbála, Kalup, Csilla, Kiss, Csaba, Kriskovics, Levente, Kun, Mária, Pál, András, Sódor, Ádam, Sárneczky, Krisztián, Szakáts, Róbert, Vida, Krisztián, Vinkó, József, Szabó, Zsófia M.
Format:	Preprint
Published:	2025
Subjects:	Solar and Stellar Astrophysics Earth and Planetary Astrophysics
Online Access:	Acceder al recurso
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_version_	1866913931661934592
author	Zsidi, Gabriella Kóspál, Ágnes Ábrahám, Péter Alecian, Evelyne Alencar, Silvia H Bouvier, Jérôme Hussain, Gaitee A. J. Manara, Carlo F. Siwak, Michal Szabó, Róbert Bora, Zsófia Cseh, Borbála Kalup, Csilla Kiss, Csaba Kriskovics, Levente Kun, Mária Pál, András Sódor, Ádam Sárneczky, Krisztián Szakáts, Róbert Vida, Krisztián Vinkó, József Szabó, Zsófia M.
author_facet	Zsidi, Gabriella Kóspál, Ágnes Ábrahám, Péter Alecian, Evelyne Alencar, Silvia H Bouvier, Jérôme Hussain, Gaitee A. J. Manara, Carlo F. Siwak, Michal Szabó, Róbert Bora, Zsófia Cseh, Borbála Kalup, Csilla Kiss, Csaba Kriskovics, Levente Kun, Mária Pál, András Sódor, Ádam Sárneczky, Krisztián Szakáts, Róbert Vida, Krisztián Vinkó, József Szabó, Zsófia M.
contents	Classical T Tauri stars are newly formed, low mass stars which may display both periodic and random variations in their brightness. The interaction between the star and its circumstellar disk is time-dependent, leading to short or long-term changes in the environment, and hence variability of the system. By compiling a large dataset with high-cadence photometric (Kepler, TESS), and high-resolution spectroscopic observations (CFHT/ESPaDOnS) of the highly variable T Tauri star DR Tau, we aim to examine the short- and long-term variability of the system, and identify the underlying physical mechanisms. Our results reveal that DR Tau exhibits stochastic photometric variability not only on daily, but also on hourly timescale with peak-to-peak amplitude of 1.4 mag probably originating from accretion related variations. Our ground-based multifilter photometry shows that the amplitude of the variability decreases with increasing wavelength. This trend towards the infrared wavelengths suggests that part of the disk may be optically thick and invariable. The spectroscopic analysis showed that the H$α$ 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, suggesting contribution from both the accretion flow and the post-shock region. DR Tau exhibits 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; and the significance of the physical mechanisms causing the observed variability changes over time.
format	Preprint
id	arxiv_https___arxiv_org_abs_2505_07684
institution	arXiv
publishDate	2025
record_format	arxiv
spellingShingle	Short- and long-term variations of the high mass accretion rate classical T Tauri star DR Tau Zsidi, Gabriella Kóspál, Ágnes Ábrahám, Péter Alecian, Evelyne Alencar, Silvia H Bouvier, Jérôme Hussain, Gaitee A. J. Manara, Carlo F. Siwak, Michal Szabó, Róbert Bora, Zsófia Cseh, Borbála Kalup, Csilla Kiss, Csaba Kriskovics, Levente Kun, Mária Pál, András Sódor, Ádam Sárneczky, Krisztián Szakáts, Róbert Vida, Krisztián Vinkó, József Szabó, Zsófia M. Solar and Stellar Astrophysics Earth and Planetary Astrophysics Classical T Tauri stars are newly formed, low mass stars which may display both periodic and random variations in their brightness. The interaction between the star and its circumstellar disk is time-dependent, leading to short or long-term changes in the environment, and hence variability of the system. By compiling a large dataset with high-cadence photometric (Kepler, TESS), and high-resolution spectroscopic observations (CFHT/ESPaDOnS) of the highly variable T Tauri star DR Tau, we aim to examine the short- and long-term variability of the system, and identify the underlying physical mechanisms. Our results reveal that DR Tau exhibits stochastic photometric variability not only on daily, but also on hourly timescale with peak-to-peak amplitude of 1.4 mag probably originating from accretion related variations. Our ground-based multifilter photometry shows that the amplitude of the variability decreases with increasing wavelength. This trend towards the infrared wavelengths suggests that part of the disk may be optically thick and invariable. The spectroscopic analysis showed that the H$α$ 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, suggesting contribution from both the accretion flow and the post-shock region. DR Tau exhibits 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; and the significance of the physical mechanisms causing the observed variability changes over time.
title	Short- and long-term variations of the high mass accretion rate classical T Tauri star DR Tau
topic	Solar and Stellar Astrophysics Earth and Planetary Astrophysics
url	https://arxiv.org/abs/2505.07684