TY - JOUR
T1 - Nearly polar orbit of the sub-Neptune HD 3167 c
T2 - Constraints on the dynamical history of a multi-planet system
AU - Dalal, S.
AU - Hébrard, G.
AU - Lecavelier Des Étangs, A.
AU - Petit, A. C.
AU - Bourrier, V.
AU - Laskar, J.
AU - König, P. C.
AU - Correia, A. C.M.
N1 - Publisher Copyright:
© 2019 S. Dalal et al.
PY - 2019/11/1
Y1 - 2019/11/1
N2 - 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.
AB - 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.
KW - Planet-star interactions
KW - Planets and satellites: fundamental parameters
KW - Planets and satellites: individual: HD 3167
KW - Techniques: radial velocities
U2 - 10.1051/0004-6361/201935944
DO - 10.1051/0004-6361/201935944
M3 - Article
AN - SCOPUS:85081691570
SN - 0004-6361
VL - 631
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A28
ER -