Related papers: Exoplanet Biosignatures: Observational Prospects
In the last decade, about a dozen giant exoplanets have been directly imaged in the IR as companions to young stars. With photometry and spectroscopy of these planets in hand from new extreme coronagraphic instruments such as SPHERE at VLT…
Advancements in our understanding of exoplanetary atmospheres, from massive gas giants down to rocky worlds, depend on the constructive challenges between observations and models. We are now on a clear trajectory for improvements in…
Observational surveys for extrasolar planets probe the diverse outcomes of planet formation and evolution. These surveys measure the frequency of planets with different masses, sizes, orbital characteristics, and host star properties. Small…
One of the most exciting scientific challenges is to detect Earth-like planets in the habitable zones of other stars in the galaxy and search for evidence of life. The ability to observe and characterise dozens of potentially Earth-like…
The Habitable Worlds Observatory (HWO) aims to characterize habitable exoplanets in search of signs of life. However, detectable life may be rare, either because abiogenesis is intrinsically contingent and unlikely, or because biospheres…
We discuss the possibility of screening the atmosphere of exomoons for habitability. We concentrate on Earth-like satellites of extrasolar giant planets (EGP) which orbit in the Habitable Zone of their host stars. The detectability of…
Giant planets within the habitable zones of the closest several stars can currently be imaged with ground-based telescopes. Within the next decade, the Extremely Large Telescopes (ELTs) will begin to image the habitable zones of a greater…
The detection of life on rocky exoplanets in the habitable zones of nearby stars would be a paradigm-shifting advance, and it is one of the greatest scientific challenges of our time. There is no single spectral feature that is an…
Microlensing offers a unique opportunity to probe exoplanets that are temperate and beyond the snow line, as small as Jovian satellites, at extragalactic distance, and even free floating exoplanets, regimes where the sensitivity of other…
Can information theory provide insights into whether exoplanets are habitable? Here we apply information theory to a range of simulated exoplanet transmission spectra as a diagnostic tool to search for potential signatures of life on…
[Abridged] We have only been able to comprehensively characterize the atmospheres of a handful of transiting planets, because most orbit faint stars. TESS will discover transiting planets orbiting the brightest stars, enabling, in…
We review the field of exoplanetary biosignatures with a main focus upon atmospheric gas-phase species. Due to the paucity of data in Earth-like planetary atmospheres a common approach is to extrapolate knowledge from the Solar System and…
The physical bases of the detection and characterisation of extrasolar planets in the reflected light and thermal emission regimes are reviewed. They both have their advantages and disadvantages, including artefacts, in the determination of…
Theory and observation for the search for life on exoplanets via atmospheric "biosignature gases" is accelerating, motivated by the capabilities of the next generation of space- and ground-based telescopes. The most observationally…
Much of the focus of exoplanet atmosphere analysis in the coming decade will be at infrared wavelengths, with the planned launches of the James Webb Space Telescope (JWST) and the Wide-Field Infrared Survey Telescope (WFIRST). However,…
Doppler and transit surveys are finding extrasolar planets of ever smaller mass and radius, and are now sampling the domain of superEarths (1-3 Earth radii). Recent results from the Doppler surveys suggest that discovery of a transiting…
The search for signs of life through the detection of exoplanet atmosphere biosignature gases is gaining momentum. Yet, only a handful of rocky exoplanet atmospheres are suitable for observation with planned next-generation telescopes. To…
In this paper, we analyze a new possible biological surface feature for habitable worlds orbiting other stars: biofluorescence. High ultraviolet (UV) and blue radiation fluxes drive the strongest biofluorescence in terrestrial fluorescent…
Thousands of extrasolar planets have been discovered, and it is clear that the galactic planetary census draws on a diversity greatly exceeding that exhibited by the solar system's planets. We review significant landmarks in the chronology…
Future space telescopes may be able to directly image $\sim$10 - 100 planets with sizes and orbits consistent with habitable surface conditions ("exo-Earth candidates" or EECs), but observers will face difficulty in distinguishing these…