The hot Jupiter and magnetic activity of V830 Tau

• Main Author: VIDOTTO, ALINE
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2017
• Subjects: stars: magnetic fields – stars: formation – stars: imaging – s tars: planetary sys- tems – stars: individual: V830 Tau – techniques: polarimetr ic; narval
• Online Access: http://hdl.handle.net/2262/79159; http://people.tcd.ie/vidottoa; https://arxiv.org/pdf/1611.02055.pdf

PUBLISHED We report results of an extended spectropolarimetric and ph otometric monitoring of the weak- line T Tauri star V830 Tau and its recently-detected newborn close-in giant planet. Our obser- vations, carried out within the MaTYSSE programme, were spr ead over 91 d, and involved the ESPaDOnS and Narval spectropolarimeters linked to the 3.6- m Canada-France-Hawaii, the 2- m Bernard Lyot and the 8-m Gemini-North Telescopes. Using Ze eman-Doppler Imaging, we characterize the surface brightness distributions, magne tic topologies and surface di ff erential rotation of V830 Tau at the time of our observations, and demo nstrate that both distributions evolve with time beyond what is expected from di ff erential rotation. We also report that near the end of our observations, V830 Tau triggered one major flar e and two weaker precursors, showing up as enhanced red-shifted emission in multiple spe ctral activity proxies. With 3 di ff erent filtering techniques, we model the radial velocity (RV ) activity jitter (of semi-amplitude 1.2 km s − 1 ) that V830 Tau generates, successfully retrieve the 68 ± 11 m s − 1 RV planet signal hiding behind the jitter, further confirm th e existence of V830 Tau b and better characterize its orbital parameters. We find that the method based on Gaussian-process regression performs best thanks to its higher ability at mod elling not only the activity jitter, but also its temporal evolution over the course of our observati ons, and succeeds at reproducing our RV data down to a rms precision of 35 m s − 1 . Our result provides new observational constraints on scenarios of star / planet formation and demonstrates the scientific potential of large-scale searches for close-in giant planets around T Ta uri stars. This paper is based on observations obtained at the CFHT (ope rated by the National Research Council of Canada / CNRC, the Institut National des Sciences de l’Univers / INSU of the Centre National de la Recherche Scientifique / CNRS of France and the University of Hawaii), at ...