Constraining stellar rotation and planetary atmospheric evolution of a dozen systems hosting sub-Neptunes and super-Earths

Abstract

We constrain the planetary atmospheric mass fraction at the time of the dispersal of the protoplanetary disk and the evolution of the stellar rotation rate for a dozen multi-planet systems that host sub-Neptunes and/or super-Earths. We employ a custom-developed Python code that we have dubbed Pasta (Planetary Atmospheres and Stellar roTation rAtes), which runs within a Bayesian framework to model the atmospheric evolution of exoplanets. The code combines MESA stellar evolutionary tracks, a model describing planetary structures, a model relating stellar rotation and activity level, and a model predicting planetary atmospheric mass-loss rates based on the results of hydrodynamic simulations. Through a MCMC scheme, we retrieved the posterior PDFs of all considered parameters. For ages older than about 2 Gyr, we find a median spin-down (i.e. $P(t)\propto t^y$) of $\bar{y}=0.38_{-0.27}^{+0.38}$, indicating a rotation decay slightly slower than classical literature values ($\approx$0.5), though still within $1\sigma$. At younger ages, we find a median spin-down (i.e. $P(t)\propto t^x$) of $\bar{x}=0.26_{-0.19}^{+0.42}$, which is below what is observed in young open clusters, though within $1\sigma$. However, these two results are likely due to a selection bias as the systems suitable to be analysed by Pasta contain at least one planet with a hydrogen-dominated atmosphere, implying that the host star has more likely evolved as a slow rotator. We further look for correlations between the initial atmospheric mass fraction of the considered planets and system parameters, but without finding any. The TESS, CHEOPS, and PLATO missions are going to be instrumental in identifying and precisely measuring systems amenable to Pasta's analysis and can thus potentially constrain planet formation and stellar evolution.

38 pages (15 in the main text), 30 figures (8 in the main text), 2 tables. Accepted for publication in A&A

References in corpus (31)

• The NumPy array: a structure for efficient numerical computation
• Improved Age Estimation for Solar-Type Dwarfs Using Activity-Rotation Diagnostics
• Planet formation around stars of various masses: The snow line and the frequency of giant planets
• Roche lobe effects on the atmospheric loss of "Hot Jupiters"
• Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
• The Mass of KOI-94d and a Relation for Planet Radius, Mass, and Incident Flux
• The Extreme Ultraviolet and X-Ray Sun in Time: High-Energy Evolutionary Tracks of a Solar-Like Star
• Revisited Mass-Radius relations for exoplanets below 120 Earth masses
• Stellar Winds on the Main-Sequence II: the Evolution of Rotation and Winds
• A generalized bayesian inference method for constraining the interiors of super Earths and sub-Neptunes
• On Correlated-noise Analyses Applied To Exoplanet Light Curves
• Revising the ages of planet-hosting stars
• Aeronomical constraints to the minimum mass and maximum radius of hot low-mass planets
• Three's Company: An additional non-transiting super-Earth in the bright HD 3167 system, and masses for all three planets
• A 1.9 Earth radius rocky planet and the discovery of a non-transiting planet in the Kepler-20 system
• Transit detection of the long-period volatile-rich super-Earth ${\nu }^2$ Lupi d with $CHEOPS$
• A comparison of gyrochronological and isochronal age estimates for transiting exoplanet host stars
• CHEOPS observations of the HD 108236 planetary system: A fifth planet, improved ephemerides, and planetary radii
• Hydrogen dominated atmospheres on terrestrial mass planets: evidence, origin and evolution
• Kepler-411: a four-planet system with an active host star
• TRADES: A new software to derive orbital parameters from observed transit times and radial velocities. Revisiting Kepler-11 and Kepler-9
• Discrepancies between isochrone fitting and gyrochronology for exoplanet host stars?
• Hydrodynamic simulations of captured protoatmospheres around Earth-like planets
• Precise Masses in the WASP-47 System
• Planet formation around stars of various masses: Hot super-Earths
• Current Population Statistics Do Not Favor Photoevaporation over Core-Powered Mass Loss as the Dominant Cause of the Exoplanet Radius Gap
• Long-Period Giant Companions to Three Compact, Multiplanet Systems
• The Kepler-11 system: evolution of the stellar high-energy emission and {initial planetary} atmospheric mass fractions
• Close-in sub-Neptunes reveal the past rotation history of their host stars: atmospheric evolution of planets in the HD3167 and K2-32 planetary systems
• Examining the Radius Valley: a Machine Learning Approach
• Why do more massive stars host larger planets?