%0 Journal Article
%T Nearly polar orbit of the sub-Neptune HD 3167 c - Constraints on the dynamical history of a multi-planet system
%A A. C. M. Correia
%A A. C. Petit
%A A. Lecavelier des ¨¦tangs
%A G. H¨¦brard
%A J. Laskar
%A P.-C. K£¿nig
%A S. Dalal
%A V. Bourrier
%J -
%D 2019
%R 10.1051/0004-6361/201935944
%X <i>Aims.<i/> 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.<i>Methods.<i/> New observations obtained with HARPS-N at the Telescopio Nazionale <i>Galileo<i/> (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.<i>Results.<i/> HD 3167 c is found to be nearly polar with sky-projected obliquity, <i>¦Ë<i/> = £¿97¡ã¡À 23¡ã. 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
%U https://www.aanda.org/articles/aa/full_html/2019/11/aa35944-19/aa35944-19.html