To prepare to interpret images of distant, rocky worlds, we can start by observing nearby worlds — Jupiter’s Galilean moons — as though they were exoplanets. Laura Mayorga (Harvard-Smithsonian CfA) presented lessons learned from analyzing more than 5,000 images of the Galilean moons taken by the Cassini probe, exploring how properties like the angle of the Sun’s illumination affect our interpretation of observations.

At this point, there are around 60 planets for which we have not only radius measurements, but also well-measured masses. ...

The final presentation of the session was given by Joseph Rodriguez (Harvard-Smithsonian CfA) — who opened by graciously crediting Astrobites for his talk title. Rodriguez presented on K2-266, a compact six-planet system in which just one of the planets — an ultra-short-period super-Earth — has a significantly misaligned orbit. How do systems like this form? Rodriguez outlines one possible explanation, in which an additional unseen companion could drive the odd...

The Search for Life

By measuring the temperature difference between the planet's hot and cold sides, the team concluded that there is a negligible amount of heat being transferred between the two. If an atmosphere were present, hot air on the dayside would naturally expand, generating winds that would transfer heat around the planet. On a rocky world with little to no atmosphere, like the Moon, there is no air present to transfer heat.

"The temperature contrast on this planet is about as big as it can possibly be," said CfA researcher Laura...