Magnetic field, activity and companions of V410 Tau

TL;DR

This study uses spectropolarimetric data to map the magnetic field and surface activity of the young star V410 Tau, revealing a heavily spotted surface, a toroidal magnetic field, weak differential rotation, and the absence of close-in giant planets.

Contribution

First detailed magnetic and activity mapping of V410 Tau using Zeeman-Doppler Imaging, showing its magnetic topology, differential rotation, and implications for planet formation.

Findings

V410 Tau has a ~550 G toroidal magnetic field.

Weak differential rotation is observed, much less than the Sun.

No hot Jupiter-mass planets within 0.1 au were detected.

Abstract

We report the analysis, conducted as part of the MaTYSSE programme, of a spectropolarimetric monitoring of the ~0.8 Myr, ~1.4 MSun disc-less weak-line T Tauri star V410 Tau with the ESPaDOnS instrument at the Canada-France-Hawaii Telescope and NARVAL at the T\'elescope Bernard Lyot, between 2008 and 2016. With Zeeman-Doppler Imaging, we reconstruct the surface brightness and magnetic field of V410 Tau, and show that the star is heavily spotted and possesses a ~550 G relatively toroidal magnetic field. We find that V410 Tau features a weak level of surface differential rotation between the equator and pole ~5 times weaker than the solar differential rotation. The spectropolarimetric data exhibit intrinsic variability, beyond differential rotation, which points towards a dynamo-generated field rather than a fossil field. Long-term variations in the photometric data suggest that spots appear at increasing latitudes over the span of our dataset, implying that, if V410 Tau has a magnetic cycle, it would have a period of more than 8 years. Having derived raw radial velocities (RVs) from our spectra, we filter out the stellar activity jitter, modeled either from our Doppler maps or using Gaussian Process Regression. Thus filtered, our RVs exclude the presence of a hot Jupiter-mass companion below ~0.1 au, which is suggestive that hot Jupiter formation may be inhibited by the early depletion of the circumstellar disc, which for V410 Tau may have been caused by the close (few tens of au) M dwarf stellar companion.