Precise High-cadence Time Series Observations of Five Variable Young Stars in Auriga with MOST

Author(s)

Ann Marie Cody, Jamie Tayar, Lynne A. Hillenbrand, Jaymie M. Matthews, Thomas Kallinger

Abstract

To explore young star variability on a large range of timescales, we

have used the MOST satellite to obtain 24 days of continuous, sub-minute

cadence, high-precision optical photometry on a field of classical and

weak-lined T Tauri stars (TTSs) in the Taurus-Auriga star formation

complex. Observations of AB Aurigae, SU Aurigae, V396 Aurigae, V397

Aurigae, and HD 31305 reveal brightness fluctuations at the 1%-10% level

on timescales of hours to weeks. We have further assessed the

variability properties with Fourier, wavelet, and autocorrelation

techniques, identifying one significant period per star. We present spot

models in an attempt to fit the periodicities, but find that we cannot

fully account for the observed variability. Rather, all stars exhibit a

mixture of periodic and aperiodic behavior, with the latter dominating

stochastically on timescales less than several days. After removal of

the main periodicity, periodograms for each light curve display

power-law trends consistent with those seen for other young accreting

stars. Several of our targets exhibited unusual variability patterns not

anticipated by prior studies, and we propose that this behavior

originates with the circumstellar disks. The MOST observations

underscore the need for investigation of TTS light variations on a wide

range of timescales in order to elucidate the physical processes

responsible; we provide guidelines for future time series observations.

 

Based on data from the MOST satellite, a Canadian Space Agency mission,

jointly operated by Systems Canada Inc. (MSCI), formerly part of

Dynacon, Inc., the University of Toronto Institute for Aerospace

Studies, and the University of British Columbia with the assistance of

the University of Vienna.

Organisation(s)

Department of Astrophysics

External organisation(s)

California Institute of Technology (Caltech), Ohio State University

Journal

The Astronomical Journal

Volume

145

No. of pages

16

ISSN

0004-6256

DOI

https://doi.org/10.1088/0004-6256/145/3/79

Publication date

03-2013

Peer reviewed

Yes

Austrian Fields of Science 2012

103004 Astrophysics, 103003 Astronomy

Keywords

Portal url

https://ucrisportal.univie.ac.at/en/publications/53a3f122-236d-42ee-8005-4fc2d1f60226