Monitoring the young planet host V1298 Tau with SPIRou: planetary system and evolving large-scale magnetic field
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Universidade Federal de Minas Gerais
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We report results of a spectropolarimetric monitoring of the young Sun-like star V1298 Tau based on data collected with the
near-infrared spectropolarimeter SPIRou at the Canada–France–Hawaii Telescope between late 2019 and early 2023. Using
Zeeman–Doppler Imaging and the Time-dependent Imaging of Magnetic Stars methods on circularly polarized spectra, we
reconstructed the large-scale magnetic topology of the star (and its temporal evolution), found to be mainly poloidal and
axisymmetric with an average strength varying from 90 to 170 G over the ∼3.5 yr of monitoring. The magnetic field features a
dipole whose strength evolves from 85 to 245 G, and whose inclination with respect to the stellar rotation axis remains stable
until 2023 where we observe a sudden change, suggesting that the field may undergo a polarity reversal, potentially similar to
those periodically experienced by the Sun. Our data suggest that the differential rotation shearing the surface of V1298 Tau is
about 1.5 times stronger than that of the Sun. When coupling our data with previous photometric results from K2 and TESS and
assuming circular orbits for all four planets, we report a 3.9σ detection of the radial velocity signature of the outermost planet
(e), associated with a most probable mass, density, and orbital period of Me = 0.95+0.33 −0.24 M, ρe = 1.66+0.61 −0.48 g cm−3, and Pe =53.0039 ± 0.0001 d, respectively. For the three inner planets, we only derive 99 per cent confidence upper limits on their mass
of 0.44, 0.22, and 0.25 M, for b, c, and d, respectively.
Abstract
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Campos magnéticos, Estrelas jovens, Estrelas - Campos magnéticos, Planetários
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Techniques: polarimetric, Stars: formation, Stars: imaging, Stars: individual: V1298 Tau, Stars: magnetic field, Stars: planetary system
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https://academic.oup.com/mnras/article/526/3/4627/7291934?login=true