The mass distribution of clumpy accretion onto the nearby young star TW Hya

Fuente: arXiv
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Main Authors: Ji, Tao, Serna, Javier, Herczeg, Gregory J., Takasao, Shinsuke, Walter, Frederick M., Chen, Yuguang, Armeni, Antonio, Johnstone, Doug, Eisloeffel, Jochen, Fang, Min, Matt, Sean P., Siwak, Michal, Venuti, Laura, Vioque, Miguel, Dai, Lixin
Format: Preprint
Published: 2025
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author Ji, Tao
Serna, Javier
Herczeg, Gregory J.
Takasao, Shinsuke
Walter, Frederick M.
Chen, Yuguang
Armeni, Antonio
Johnstone, Doug
Eisloeffel, Jochen
Fang, Min
Matt, Sean P.
Siwak, Michal
Venuti, Laura
Vioque, Miguel
Dai, Lixin
author_facet Ji, Tao
Serna, Javier
Herczeg, Gregory J.
Takasao, Shinsuke
Walter, Frederick M.
Chen, Yuguang
Armeni, Antonio
Johnstone, Doug
Eisloeffel, Jochen
Fang, Min
Matt, Sean P.
Siwak, Michal
Venuti, Laura
Vioque, Miguel
Dai, Lixin
contents The proliferation of high time-resolution and decades-long monitoring of classical T Tauri stars provides a vast opportunity to test the variability of the star-disk connections. However, most monitoring surveys use single broad-band filters, which makes the conversion of photometric variability into accretion rate difficult. In this study, we analyze accretion bursts onto the nearby young star TW Hya over short (hours, days) and long (months, years) timescales by calibrating TESS and ASAS-SN $g$-band photometry to accretion rates with simultaneous spectroscopy. The high cadence TESS light curve shows bursts of accretion in clumps with masses from a sensitivity limit of $\sim10^{-13}$~M$_\odot$ up to $3\times 10^{-11}$\,M$_\odot$. The average burst duration of 1.8 days is longer than a simple estimate of the thermal response timescale, supporting the interpretation that the photometric variability probes the instantaneous accretion rate. The reset timescale of 1.2--2 days derived from the structure function and previously reported quasi-periods of 3.5--4 days are consistent with bursts that may be related to the different rotation between the stellar magnetosphere and inner disk or with azimuthal asymmetries in the inner disk. The near-daily ASAS-SN light curve across 8 years reveals some seasonal changes in brightness with a standard deviation of $\sim 0.13$ mag, about half of the scatter seen on short timescales. This study demonstrates the importance of coordinating contemporaneous multi-epoch spectroscopy with time domain surveys to interpret light curves of young stars.
format Preprint
id arxiv_https___arxiv_org_abs_2512_17074
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The mass distribution of clumpy accretion onto the nearby young star TW Hya
Ji, Tao
Serna, Javier
Herczeg, Gregory J.
Takasao, Shinsuke
Walter, Frederick M.
Chen, Yuguang
Armeni, Antonio
Johnstone, Doug
Eisloeffel, Jochen
Fang, Min
Matt, Sean P.
Siwak, Michal
Venuti, Laura
Vioque, Miguel
Dai, Lixin
Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
The proliferation of high time-resolution and decades-long monitoring of classical T Tauri stars provides a vast opportunity to test the variability of the star-disk connections. However, most monitoring surveys use single broad-band filters, which makes the conversion of photometric variability into accretion rate difficult. In this study, we analyze accretion bursts onto the nearby young star TW Hya over short (hours, days) and long (months, years) timescales by calibrating TESS and ASAS-SN $g$-band photometry to accretion rates with simultaneous spectroscopy. The high cadence TESS light curve shows bursts of accretion in clumps with masses from a sensitivity limit of $\sim10^{-13}$~M$_\odot$ up to $3\times 10^{-11}$\,M$_\odot$. The average burst duration of 1.8 days is longer than a simple estimate of the thermal response timescale, supporting the interpretation that the photometric variability probes the instantaneous accretion rate. The reset timescale of 1.2--2 days derived from the structure function and previously reported quasi-periods of 3.5--4 days are consistent with bursts that may be related to the different rotation between the stellar magnetosphere and inner disk or with azimuthal asymmetries in the inner disk. The near-daily ASAS-SN light curve across 8 years reveals some seasonal changes in brightness with a standard deviation of $\sim 0.13$ mag, about half of the scatter seen on short timescales. This study demonstrates the importance of coordinating contemporaneous multi-epoch spectroscopy with time domain surveys to interpret light curves of young stars.
title The mass distribution of clumpy accretion onto the nearby young star TW Hya
topic Solar and Stellar Astrophysics
Earth and Planetary Astrophysics
url https://arxiv.org/abs/2512.17074