Extrasolar Planets: July 2020

Understanding the total flux and polarization signals of Earth-like planets and their spectral and temporal variability is essential for the future characterization of such exoplanets.

Photometric variability of a directly imaged exo-Earth conveys spatial information on its surface and can be used to retrieve a two-dimensional geography and axial tilt of the planet (spin-orbit tomography).

Using radial-velocity data from the Habitable-zone Planet Finder, we have measured the mass of the Neptune-sized planet K2-25b, as well as the obliquity of its M4.5-dwarf host star in the 600-800MYr Hyades cluster.

The rediscovery of a lost planet could pave the way for the detection of a world within the habitable 'Goldilocks zone' in a distant solar system.

Many exoplanets known today are "super-Earths", with a radius 1.3 times that of Earth, and "mini-Neptunes", with 2.4 Earth radii.

Aims: The secondary atmospheres of terrestrial planets form and evolve as a consequence of interaction with the interior over geological time. We aim to quantify the influence of planetary bulk composition on interior--atmosphere evolution to aid the interpretation of future observations of terrestrial exoplanet atmospheres.

Observations suggest an abundance of water and paucity of methane in the majority of observed exoplanetary atmospheres. We isolate the effect of atmospheric processes to investigate possible causes.

Protoplanets are able to accrete primordial atmospheres when embedded in the gaseous protoplanetary disk. The formation and structure of the proto-atmosphere are subject to the planet--disk environment and orbital effects.

The nearby super-Earth 55 Cnc e orbits a bright (V = 5.95 mag) star with a period of ~ 18 hours and a mass of ~ 8 Earth masses. Its atmosphere may be water-rich and have a large scale-height, though attempts to characterize it have yielded ambiguous results.