Mid-infrared time-domain study of recent dust production events in the extreme debris disc of TYC 4209-1322-1

Abstract

Extreme debris discs are characterized by unusually strong mid-infrared excess emission, which often proves to be variable. The warm dust in these discs is of transient nature and is likely related to a recent giant collision occurring close to the star in the terrestrial region. Here we present the results of a 877 days long, gap-free photometric monitoring performed by the Spitzer Space Telescope of the recently discovered extreme debris disc around TYC 4209-1322-1. By combining these observations with other time-domain optical and mid-infrared data, we explore the disc variability of the last four decades, with particular emphasis on the last 12 years. During the latter interval the disc showed substantial changes, the most significant was the brightening and subsequent fading between 2014 and 2018 as outlined in WISE data. The Spitzer light curves outline the fading phase and a subsequent new brightening of the disc after 2018, revealing an additional flux modulation with a period of ∼39 days on top of the long-term trend. We found that all these variations can be interpreted as the outcome of a giant collision that happened at an orbital radius of ∼0.3 au sometime in 2014. Our analysis implies that a collision on a similar scale could have taken place around 2010, too. The fact that the disc was already peculiarly dust rich 40 years ago, as implied by IRAS data, suggests that these dust production events belong to a chain of large impacts triggered by an earlier even more catastrophic collision.

RZ Piscium Hosts a Compact and Highly Perturbed Debris Disk

“…More than half of the EDDs are known to show photometry variability either in their total infrared outputs through Spitzer and Wide-field Infrared Survey Explorer (WISE) monitoring (Meng et al 2014(Meng et al , 2015Su et al 2019Su et al , 2020Moór et al 2021Moór et al , 2022Rieke et al 2021) or by irregular dips through routine all-sky optical surveys (Gaidos et al 2019;Melis et al 2021;Powell et al 2021). The characteristics of the dips are best described as star-sized dust clumps, presumably generated by large collisions within a few astronomical units, passing in front of the stars (de Wit et al 2013).…”