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The radius distribution of small, close-in exoplanets has recently been shown to be bimodal. The photoevaporation model predicted this bimodality. In the photoevaporation scenario, some planets are completely stripped of their primordial H/He atmospheres, whereas others retain them. Comparisons between the photoevaporation model and observed planetary populations have the power to unveil details of the planet population inaccessible by standard observations, such as the core mass distribution and core composition. In this work, we present a hierarchical inference analysis on the distribution of close-in exoplanets using forward-models of photoevaporation evolution. We use this model to constrain the planetary distributions for core composition, core mass and initial atmospheric mass fraction. We find that the core-mass distribution is peaked, with a peak-mass of $sim 4$M$_oplus$. The bulk core-composition is consistent with a rock/iron mixture that is ice-poor and ``Earth-like; the spread in core-composition is found to be narrow ($lesssim 16%$ variation in iron-mass fraction at the 2$sigma$ level) and consistent with zero. This result favours core formation in a water/ice poor environment. We find the majority of planets accreted a H/He envelope with a typical mass fraction of $sim 4%$; only a small fraction did not accrete large amounts of H/He and were ``born-rocky. We find four-times as many super-Earths were formed through photoevaporation, as formed without a large H/He atmosphere. Finally, we find core-accretion theory over-predicts the amount of H/He cores would have accreted by a factor of $sim 5$, pointing to additional mass-loss mechanisms (e.g. ``boil-off) or modifications to core-accretion theory.
With the increasing number of exoplanets discovered, statistical properties of the population as a whole become unique constraints on planet formation models provided a link between the description of the detailed processes playing a role in this for
It is believed that Al-26, a short-lived (t1/2 = 0.73 Ma) and now extinct radionuclide, was uniformly distributed in the nascent Solar System with the initial Al-26/Al-27 ratio of ~5.2times10-5, suggesting its external stellar origin. However, the st
Gamma Ray Bursts are detectable in the gamma-ray band if their jets are oriented towards the observer. However, for each GRB with a typical theta_jet, there should be ~2/theta_jet^2 bursts whose emission cone is oriented elsewhere in space. These off
We report a new free-floating planet (FFP) candidate, KMT-2017-BLG-2820, with Einstein radius $theta_esimeq 6,muas$, lens-source relative proper motion $mu_rel simeq 8,masyr$, and Einstein timescale $t_e=6.5,$hr. It is the third FFP candidate found i
The CoRoT (COnvection, internal ROtation and Transiting planets) space mission was launched in the last days of 2006, becoming the first major space mission dedicated to the search for and study of exoplanets, as well as doing the same for asteroseis