A new kind of animal in the exoplanet zoo
astrobites | 2018 Jan 05
Atmospheric circulation, chemistry, and infrared spectra of Titan-like
Kerrin Hensley wrote:
By now, exoplanet enthusiasts will be familiar with hot Jupiters, super-Earths, mini Neptunes, and even exo-Venuses, to name just a few. As the search continues, astronomers are finding colder and smaller planets, making possible the discovery of more Solar System analogs. In today’s paper, Lora et al. consider exoplanets similar to one of the most tantalizingly Earth-like yet alien bodies in the Solar System: Titan. ...
In today’s paper, Lora et al. use theoretical models to investigate the atmospheres of Titan-like exoplanets orbiting Sun-like stars as well as K and M dwarfs, which are smaller and redder than the Sun. Thanks to Cassini, we already have an idea of what Titan might look like masquerading as an exoplanet around a Sun-like star, but Titan takes about 30 years to orbit the Sun; that’s a long time to wait to detect and confirm an exoplanet! Around an M dwarf, a planet with the same effective temperature as Titan (~80 K) takes only about 2 years to complete an orbit—much easier and quicker to detect. Titan-like exoplanets don’t need to crowd M dwarfs as closely as Earth-like planets do, so they are less susceptible to the notoriously nasty space weather of cool stars and they are less likely to be tidally locked. Though neither issue immediately disqualifies M dwarf planets from the habitability contest, considering a cooler planet appears to solve both problems at once. ...
exoplanets around different stellar types
- Juan M. Lora, Tiffany Kataria, Peter Gao