Habitable Zones & Global Climate: April 2020

In the near future, extremely-large ground-based telescopes may conduct some of the first searches for life beyond the solar system. High-spectral resolution observations of reflected light from nearby exoplanetary atmospheres could be used to search for the biosignature oxygen.

The "liquid water habitable zone" (HZ) concept is predicated on the ability of the silicate weathering feedback to stabilize climate across a wide range of instellations.

Very little experimental work has been done to explore the properties of photochemical hazes formed in atmospheres with very different compositions or temperatures than that of the outer solar system or of early Earth.

Astrophysical observations have shown that Neptune-like water-rich exoplanets are common in our galaxy. These "water worlds" are believed to be covered with a thick layer of water, hundreds to thousands of miles deep, above a rocky mantle.

Over large timescales, a terrestrial planet may be driven towards spin-orbit synchronous rotation by tidal forces. In this particular configuration, the planet exhibits permanent dayside and nightside, which may induce strong day-night temperature gradients.

In their recent comment, Cockell et al. argue that the habitability of an environment is fundamentally a binary property; that is to say, an environment can either support the metabolic processes of a given organism or not.

While everybody agrees that our blue planet is rich in water, this observation is at odd, first, with the exploration of other rocky planets, genuinely lacking surface water, and second, with the idea of a giant impact between the proto-Earth and a planetary embryo the size of Mars that created the Moon.

Photometric variation of a directly imaged planet contains information on both the geography and spectra of the planetary surface. We propose a novel technique that disentangles the spatial and spectral information from the multi-band reflected light curve.

We develop a new retrieval scheme for obtaining two-dimensional surface maps of exoplanets from scattered light curves. In our scheme, the combination of the L1-norm and Total Squared Variation, which is one of the techniques used in sparse modeling, is adopted to find the optimal map.

The search for life on exoplanets is one of the grand scientific challenges of our time.

The habitable zone is the main tool that mission architectures utilize to select potentially habitable planets for follow up spectroscopic observation.