2020/08/31 by Fei Dai, Arpita Roy, Benjamin Fulton +44 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Atmospheric model #Celestial mechanics #Constraint (computer-aided design) #Differential (mechanical device) #Orbit (dynamics) #Planet #Planetary system #Stellar, planetary, and galactic studies #Terrestrial planet #Transit (satellite) #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.3847/1538-3881/abb3bd
Accepted to AJ
arxiv created 2020/08/31 · openalex created_date 2020/09/08 · openalex publication_date 2020/09/30 · arxiv updated 2020/10/07 · openalex updated_date 2026/08/06
Abstract We report the measurement of a spectroscopic transit of TOI-1726c, one of two planets transiting a G-type star with V = 6.9 in the Ursa Major Moving Group (∼400 Myr). With a precise age constraint from cluster membership, TOI-1726 provides a great opportunity to test various obliquity excitation scenarios that operate on different timescales. By modeling the Rossiter–McLaughlin (RM) effect, we derived a sky-projected obliquity of . This result rules out a polar/retrograde orbit and is consistent with an aligned orbit for planet c. Considering the previously reported, similarly prograde RM measurement of planet b and the transiting nature of both planets, TOI-1726 tentatively conforms to the overall picture that compact multitransiting planetary systems tend to have coplanar, likely aligned orbits. TOI-1726 is also a great atmospheric target for understanding differential atmospheric loss of sub-Neptune planets (planet b 2.2 R ⊕ and c 2.7 R ⊕ both likely underwent photoevaporation). The coplanar geometry points to a dynamically cold history of the system that simplifies any future modeling of atmospheric escape.