Related papers: The mass-radius relation of intermediate-mass plan…
Small planets ($R_{p} \leq 4 R_{\oplus}$) are divided into rocky super-Earths and gaseous sub-Neptunes separated by a radius gap, but the mechanisms that produce these distinct planet populations remain unclear. Binary stars are the only…
The detection of hot atomic hydrogen and heavy atoms and ions at high altitudes around close-in extrasolar giant planets (EGPs) such as HD209458b imply that these planets have hot and rapidly escaping atmospheres that extend to several…
The detailed interior structure models of super-Earth planets show that there is degeneracy in the possible bulk compositions of a super-Earth at a given mass and radius, determined via radial velocity and transit measurements,…
Planetary embryos form protoplanets via mutual collisions, which can lead to the development of magma oceans. During their solidification, large amounts of the mantles' volatile contents may be outgassed. The resulting H$_2$O/CO$_2$…
Atmospheric mass-loss is known to play a leading role in sculpting the demographics of small, close-in exoplanets. Knowledge of how such planets evolve allows one to ``rewind the clock'' to infer the conditions in which they formed. Here,…
At least 30\% of main sequence stars host planets with sizes of between 1 and 4 Earth radii and orbital periods of less than 100 days. We use N-body simulations including a model for gas-assisted pebble accretion and disk--planet tidal…
Close-in giant planets are thought to have formed in the cold outer regions of planetary systems and migrated inward, passing through the orbital parameter space occupied by the terrestrial planets in our own Solar System. We present…
Kepler has found hundreds of Neptune-size (2-6 R_Earth) planet candidates within 0.5 AU of their stars. The nature of the vast majority of these planets is not known because their masses have not been measured. Using theoretical models of…
The recently discovered low-density "super-Earths" Kepler-11b, Kepler-11f, Kepler-11d, Kepler-11e, and planets such as GJ 1214b represent most likely planets which are surrounded by dense H/He envelopes or contain deep H2O oceans also…
Current observations indicate that the planet formation process often produces multiple planet systems with nearly circular orbits, regular spacing, a narrow range of inclination angles, and similar planetary masses of order $m_{\rm…
The migration of planets plays an important role in the early planet-formation process. An important problem has been that standard migration theories predict very rapid inward migration, which poses problems for population synthesis…
The ever-expanding catalog of detected super-Earths calls for theoretical studies of their properties in the case of a substantial water layer. This work considers such water planets with a range of masses and water mass fractions (2 to 5…
The widespread prevalence of close-in, nearly coplanar super-Earth- and sub-Neptune-sized planets in multiple-planet systems was one of the most surprising results from the Kepler mission. By studying a uniform sample of Kepler "multis"…
We explore atmospheric escape from close-in exoplanets with the highest mass loss rates. First, we locate the transition from stellar X-ray and UV-driven escape to rapid Roche lobe overflow, which occurs once the 10-100 nbar pressure level…
The observational detection of a localized reduction in the small planet occurrence rate, sometimes termed a 'gap', is an exciting discovery because of the implications for planet evolutionary history. This gap appears to define a…
The physics of planet formation is investigated using a population synthesis approach. We develop a simple model for planetary growth including pebble and gas accretion, and orbital migration in an evolving protoplanetary disk. The model is…
The origin of close-in giant planets is a key open question in planet formation theory. The two leading models are (i) formation at the outer disk followed by migration and (ii) in situ formation. In this work we determine the atmospheric…
NASA's TESS mission is expected to discover hundreds of M dwarf planets. However, few studies focus on how planets form around low-mass stars. We aim to better characterize the formation process of M dwarf planets to fill this gap and aid…
The Kepler transit survey with follow-up spectroscopic observations has discovered numerous super-Earth sized planets and revealed intriguing features of their sizes, orbital periods, and their relations between adjacent planets. For the…
The majority of discovered exoplanetary systems harbour a new class of planets, bodies typically several times more massive than Earth but orbiting their host stars well inside the orbit of Mercury. The origin of these close-in super-Earths…