What catches your eye in this description of an exoplanetary system? Start with a ‘hot Jupiter,’ with a radius 0.87 times that of our Jupiter and an orbit of 7.1 days. This is WASP-132b, confirmed in 2016, and first discovered through the labors of the Wide-Angle Search for Planets program. Subsequent confirmation came through the CORALIE spectrograph installed on the Euler telescope at the European Southern Observatory’s La Silla site. This world orbits a K-class star 403 light years out in Lupus. The CORALIE measurements gave hints of another giant planet in a long period orbit. The system came still further into focus in 2021, when observations from TESS (Transiting Exoplanet Survey Satellite) showed a transiting super-Earth with a diameter of 1.8 Earth radii in a tight orbit of 1.01 days. The mass of the planet, as measured by the HARPS spectrograph at La Silla, is six times that of Earth. So we have both a hot-Jupiter and a super-Earth hugging the star, along with an outer gas...

Last Friday’s post on K-dwarfs as home to what researchers have taken to calling ‘superhabitable’ worlds has caught the eye of Dave Moore, a long-time Centauri Dreams correspondent and author. Readers will recall his deep dives into habitability concepts in such essays as The “Habitability" of Worlds and Super Earths/Hycean Worlds, not to mention his work on SETI (see If Loud Aliens Explain Human Earliness, Quiet Aliens Are Also Rare). Dave sent this in as a comment but I asked him to post it at the top because it so directly addresses the topic of habitability prospects around K-dwarfs, based on a quick survey of known planetary systems. It's a back of the envelope overview, but one that implies habitable planets around stars like these may be more difficult to find than we think. by Dave Moore To see whether K dwarfs made a good target for habitable planets, I decided to look into the prevalence and type of planets around K dwarfs and got carried away looking at the specs for 500...

We think of Earth as our standard for habitability, and thus the goal of finding an ‘Earth 2.0’ is to identify living worlds like ours orbiting similar Sun-like stars. But maybe Earth isn’t the best standard. Are there ways planets can be more habitable than our own, and if so where would we find them? That’s the tantalizing question posed in a paper by Iva Vilović (Technische Universität Berlin), René Heller (Max-Planck-Institut für Sonnensystemforschung) and colleagues in Germany and India. Heller has previously worked this issue in a significant paper with John Armstrong (citation below); see as well The Best of All Possible Worlds, which ran here in 2020. The term for the kind of world we are looking for is ‘superhabitable,’ and the aim of this study is to extend the discussion of K-class stars as hosts by modeling the atmospheres we may find on planets there. While much attention has focused on M-class red dwarfs, the high degree of flare activity coupled with long pre-main...