Tyc 8241 2652 1 And The Case Of The Disappearing Disk: No Smoking Gun Yet

TYC 8241 2652 1 is a young star that showed a strong mid-infrared (mid-IR, \n8-25 mu) excess in all observations before 2008 consistent with a dusty disk. \nBetween 2008 and 2010 the mid-IR luminosity of this system dropped dramatically \nby at least a factor of 30 suggesting a loss of dust mass of an order of \nmagnitude or more. We aim to constrain possible models including removal of \ndisk material by stellar activity processes, the presence of a binary \ncompanion, or other explanations suggested in the literature. We present new \nX-ray observations, optical spectroscopy, near-IR interferometry, and mid-IR \nphotometry of this system to constrain its parameters and further explore the \ncause of the dust mass loss. In X-rays TYC 8241 2652 1 has all properties \nexpected from a young star: Its luminosity is in the saturation regime and the \nabundance pattern shows enhancement of O/Fe. The photospheric Ha line is filled \nwith a weak emission feature, indicating chromospheric activity consistent with \nthe observed level of coronal emission. Interferometry does not detect a \ncompanion and sets upper limits on the companion mass of 0.2, 0.35, 0.1 and \n0.05 M_sun at projected physical separations of 0.1-4 AU,4-5 AU, 5-10 AU, and \n10-30 AU, respectively (assuming a distance of 120.9 pc). Our mid-IR \nmeasurements, the first of the system since 2012, are consistent with the \ndepleted dust level seen after 2009. The new data confirms that stellar \nactivity is unlikely to destroy the dust in the disk and shows that scenarios \nwhere either TYC 8241 2652 1 heats the disk of a binary companion or a \npotential companion heats the disk of TYC 8241 2652 1 are unlikely.