Volume 631, November 2019
|Number of page(s)||12|
|Section||Planets and planetary systems|
|Published online||15 October 2019|
Nearly polar orbit of the sub-Neptune HD 3167 c
Constraints on the dynamical history of a multi-planet system
Institut d’astrophysique de Paris (IAP), UMR 7095 CNRS, Université Pierre & Marie Curie,
98bis Boulevard Arago,
2 Observatoire de Haute-Provence (OHP), CNRS, Université d’Aix-Marseille, 04870 Saint-Michel-l’Observatoire, France
3 IMCCE, CNRS-UMR 8028, Observatoire de Paris, PSL University, Sorbonne Université, 77 avenue Denfert-Rochereau, 75014 Paris, France
4 Observatoire de l’Université de Geneve, 51 chemin des Maillettes, Versoix, Switzerland
5 CFisUC, Department of Physics, University of Coimbra, 3004-516 Coimbra, Portugal
Accepted: 26 June 2019
Aims. We present the obliquity measurement, that is, the angle between the normal angle of the orbital plane and the stellar spin axis, of the sub-Neptune planet HD 3167 c, which transits a bright nearby K0 star. We study the orbital architecture of this multi-planet system to understand its dynamical history. We also place constraints on the obliquity of planet d based on the geometry of the planetary system and the dynamical study of the system.
Methods. New observations obtained with HARPS-N at the Telescopio Nazionale Galileo (TNG) were employed for our analysis. The sky-projected obliquity was measured using three different methods: the Rossiter-McLaughlin anomaly, Doppler tomography, and reloaded Rossiter-McLaughlin techniques. We performed the stability analysis of the system and investigated the dynamical interactions between the planets and the star.
Results. HD 3167 c is found to be nearly polar with sky-projected obliquity, λ = −97°± 23°. This misalignment of the orbit of planet c with the spin axis of the host star is detected with 97% confidence. The analysis of the dynamics of this system yields coplanar orbits of planets c and d. It also shows that it is unlikely that the currently observed system can generate this high obliquity for planets c and d by itself. However, the polar orbits of planets c and d could be explained by the presence of an outer companion in the system. Follow-up observations of the system are required to confirm such a long-period companion.
Key words: techniques: radial velocities / planets and satellites: fundamental parameters / planet–star interactions / planets and satellites: individual: HD 3167
© S. Dalal et al. 2019
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.