Extrasolar Planets: June 2021

We present high angular resolution imaging observations of 517 host stars of TESS exoplanet candidates using the `Alopeke and Zorro speckle cameras at Gemini North and South. The sample consists mainly of bright F, G, K stars at distances of less than 500 pc.

Clouds are expected to form in a wide range of conditions in the atmosphere of exoplanets given the large range of possible condensible species.

We can't detect them yet, but radio signals from distant solar systems could provide valuable information about the characteristics of their planets.

Formation of hazes at microbar pressures has been explored by theoretical models of exoplanet atmospheres to explain Rayleigh scattering and/or featureless transmission spectra, however observational evidence of aerosols in the low pressure formation environments has proved elusive.

Context. The discovery of an extrasolar planet with an ocean has crucial importance in the search for life beyond Earth.

Since planet occurrence and primordial atmospheric retention probability increase with period, the occurrence-weighted median planets discovered by transit surveys may bear little resemblance to the low-occurrence, short-period planets sculpted by atmospheric escape ordinarily used to calibrate mass--radius relations and planet formation models.

Similar to the case of solar system planets, reflected starlight from exoplanets is expected to be polarized due to atmospheric scattering and the net disk integrated polarization should be non-zero owing to the asymmetrical illumination of the planetary disk.

An international group of collaborators, including scientists from NASA's Jet Propulsion Laboratory and The University of New Mexico, have discovered a new, temperate sub-Neptune sized exoplanet with a 24-day orbital period orbiting a nearby M dwarf star.

The preponderance of white dwarfs in the Milky Way were formed from the remnants of stars of the same or somewhat higher mass as the Sun, i.e., from G-stars. We know that life can exist around G-stars.

Many exoplanets are discovered in binary star systems in internal or in circumbinary orbits. Whether the planet can be habitable or not depends on the possibility to maintain liquid water on its surface, and therefore on the luminosity of its host stars and on the dynamical properties of the planetary orbit.

L 98-59 is an M3V dwarf star that hosts three small (R < 1.6 Earth radii) planets. The host star is bright (K = 7.1) and nearby (10.6 pc), making the system a prime target for follow-up characterization with the Hubble Space Telescope (HST) and the upcoming James Webb Space Telescope (JWST).

Stellar activity poses one of the main obstacles for the detection and characterisation of small exoplanets around cool stars, as it can induce radial velocity (RV) signals that can hide or mimic the presence of planetary companions.

We report the discovery of two planetary systems, namely G 264-012, an M4.0 dwarf with two terrestrial planets (Mbsini=2.50+0.29−0.30 M⊕ and Mcsini=3.75+0.48−0.47 M⊕), and Gl 393, a bright M2.0 dwarf with one terrestrial planet (Mbsini=1.71±0.24 M⊕).