One year of AU Mic with HARPS: I-measuring the masses of the two transiting planets
Monthly Notices of the Royal Astronomical Society Oxford University Press 512:2 (2022) 3060-3078
Abstract:
The system of two transiting Neptune-sized planets around the bright, young M-dwarf AU Mic provides a unique opportunity to test models of planet formation, early evolution, and star-planet interaction. However, the intense magnetic activity of the host star makes measuring the masses of the planets via the radial velocity (RV) method very challenging. We report on a 1-yr, intensive monitoring campaign of the system using 91 observations with the HARPS spectrograph, allowing for detailed modelling of the ∼600 m s-1 peak-to-peak activity-induced RV variations. We used a multidimensional Gaussian Process framework to model these and the planetary signals simultaneously. We detect the latter with semiamplitudes of Kb = 5.8 ± 2.5 m s-1 and Kc = 8.5 ± 2.5 m s-1, respectively. The resulting mass estimates, Mb = 11.7 ± 5.0 M⊕ and Mc = 22.2 ± 6.7 M⊕, suggest that planet b might be less dense, and planet c considerably denser than previously thought. These results are in tension with the current standard models of core-accretion. They suggest that both planets accreted a H/He envelope that is smaller than expected, and the trend between the two planets' envelope fractions is the opposite of what is predicted by theory.Escaping Helium from TOI 560.01, a Young Mini-Neptune
The Astronomical Journal American Astronomical Society 163:2 (2022) 67
K2-99 revisited: a non-inflated warm Jupiter, and a temperate giant planet on a 522-d orbit around a subgiant
Monthly Notices of the Royal Astronomical Society Oxford University Press (OUP) 510:4 (2022) 5035-5049
A New Third Planet and the Dynamical Architecture of the HD33142 HD 33142 Planetary System
ASTRONOMICAL JOURNAL 164:4 (2022) ARTN 156
Transit timings variations in the three-planet system: TOI-270
Monthly Notices of the Royal Astronomical Society Oxford University Press 510:4 (2021) 5464-5485