Young Exoplanet Transit Initiative follow-up observations of the T Tauri star CVSO 30 with transit-like dips

Abstract

The T Tauri star CVSO 30, also known as PTFO 8-8695, was studied intensively with ground based telescopes as well as with satellites over the last decade. It showed a variable light curve with additional repeating planetary transit-like dips every ∼10.8 h. However, these dimming events changed in depth and duration since their discovery and from autumn 2018 on, they were not even present or near the predicted observing times. As reason for the detected dips and their changes within the complex light curve, e.g. a disintegrating planet, a circumstellar dust clump, stellar spots, possible multiplicity and orbiting clouds at a Keplerian co-rotating radius were discussed and are still under debate. In this paper, we present additional optical monitoring of CVSO 30 with the meter class telescopes of the Young Exoplanet Transit Initiative in Asia and Europe over the last seven years and characterize CVSO 30 with the new Early Data Release 3 of the ESA Gaia Mission. As a result, we describe the evolution of the dimming events in the optical wavelength range since 2014 and present explanatory approaches for the observed variabilities. We conclude that orbiting clouds of gas at a Keplerian co-rotating radius are the most promising scenario to explain most changes in CVSO 30’s light curve.

Full-frame Data Reduction Method: A Data Mining Tool to Detect the Potential Variations in Optical Photometry

“…Assuming that the shallow dip in No. 26 J210141+340327 is an intrinsic rather than artificial phenomenon, based on the similarity in morphology of the light curve with the exoplanet transits (see Bischoff et al 2020;Tran et al 2022), we boldly suspect that this may be a transitlike dip despite the insufficient evidence provided by these observation data alone.…”