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Pulsed Accretion in the T Tauri Binary TWA 3A

Tofflemire, Benjamin M. and Mathieu, Robert D. and Herczeg, Gregory J. and Akeson, Rachel L. and Ciardi, David R. (2017) Pulsed Accretion in the T Tauri Binary TWA 3A. Astrophysical Journal Letters, 842 (2). Art. No. L12. ISSN 2041-8205.

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TWA 3A is the most recent addition to a small group of young binary systems that both actively accrete from a circumbinary disk and have spectroscopic orbital solutions. As such, it provides a unique opportunity to test binary accretion theory in a well-constrained setting. To examine TWA 3A's time-variable accretion behavior, we have conducted a two-year, optical photometric monitoring campaign, obtaining dense orbital phase coverage (~20 observations per orbit) for ~15 orbital periods. From U-band measurements we derive the time-dependent binary mass accretion rate, finding bursts of accretion near each periastron passage. On average, these enhanced accretion events evolve over orbital phases 0.85 to 1.05, reaching their peak at periastron. The specific accretion rate increases above the quiescent value by a factor of ~4 on average but the peak can be as high as an order of magnitude in a given orbit. The phase dependence and amplitude of TWA 3A accretion is in good agreement with numerical simulations of binary accretion with similar orbital parameters. In these simulations, periastron accretion bursts are fueled by periodic streams of material from the circumbinary disk that are driven by the binary orbit. We find that TWA 3A's average accretion behavior is remarkably similar to DQ Tau, another T Tauri binary with similar orbital parameters, but with significantly less variability from orbit to orbit. This is only the second clear case of orbital-phase-dependent accretion in a T Tauri binary.

Item Type:Article
Related URLs:
URLURL TypeDescription
Herczeg, Gregory J.0000-0002-7154-6065
Akeson, Rachel L.0000-0001-9674-1564
Ciardi, David R.0000-0002-5741-3047
Additional Information:© 2017 American Astronomical Society. Received 2017 May 15. Accepted 2017 May 30. Published 2017 June 14. The authors would like to thank Lisa Prato for providing the TWA 3A spectroscopic orbital solution prior to its publication. This work makes use of observations from the LCO network and the CTIO 1.3 m telescope operated by the SMARTS Consortium. This research has made use of the VizieR catalogue access tool, CDS, Strasbourg, France. B.T. acknowledges funding from Sigma Xi Honors Society and from the University of Wisconsin-Madison Graduate School.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
University of Wisconsin-MadisonUNSPECIFIED
Subject Keywords:accretion, accretion disks; binaries: close; stars: formation; stars: individual (TWA 3A)
Issue or Number:2
Record Number:CaltechAUTHORS:20170615-125852096
Persistent URL:
Official Citation:Benjamin M. Tofflemire et al 2017 ApJL 842 L12
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78253
Deposited By: Ruth Sustaita
Deposited On:15 Jun 2017 20:22
Last Modified:03 Oct 2019 18:06

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