相关论文: Biofluorescent Worlds I: Global Biological Fluores…

In the modern search for life elsewhere in the Universe, we are broadly looking for the following: the planets similar to Earth - physical indicators of habitability, and the manifestation of life - the biological signatures. A biosignature…

The first detected member of a new astronomical class is often not representative of the underlying population, but instead reflects the selection effects of the observing technique that found it. We apply this idea to the first remote…

Terrestrial exoplanets in habitable zones are ubiquitous. It is, however, unknown which have Earth-like or Venus-like climates. Distinguishing different planet-types is crucial for determining whether a planet could be habitable. We…

In this paper we discuss how we can read a planets spectrum to assess its habitability and search for the signatures of a biosphere. After a decade rich in giant exoplanet detections, observation techniques have now reached the ability to…

With the discovery of rocky planets in the temperate habitable zone (HZ) of the close-by cool star TRAPPIST-1 the question of whether such planets could harbour life arises. Habitable planets around red dwarf stars can orbit in radiation…

Many past studies have predicted the steady-state production and maintenance of abiotic O$_2$ and O$_3$ in the atmospheres of CO$_2$-rich terrestrial planets orbiting M dwarf stars. However, the time-dependent responses of these planetary…

Numerical simulations of starlight that is reflected by Earth-like exoplanets predict habitability signatures that can be searched for with future telescopes. We explore signatures of water oceans in the flux and polarization spectra of…

How can scientists conclude with high confidence that an exoplanet hosts life? As telescopes come on line over the next 20 years that can directly observe photons from terrestrial exoplanets, this question will dictate the activities of…

Among the many recommendations of the Decadal Survey on Astronomy and Astrophysics 2020, we found that a priority area of research is to pave the pathways towards finding and characterizing habitable worlds. In this context, we aim to…

In the search for life on other planets, the presence of photosynthetic vegetation may be detectable from the colors of light it reflects. On the modern Earth, this spectral reflectance is characterized by an increase in reflectance between…

Much of the focus of exoplanet atmosphere analysis in the coming decade will be atinfrared wavelengths, with the planned launches of the James Webb Space Telescope (JWST) and the Wide-Field Infrared Survey Telescope (WFIRST). However,…

Observations of molecular hydrogen (H$_2$) fluorescence are a potentially useful tool for measuring the H$_2$ abundance in exoplanet atmospheres. This emission was previously observed in M$\;$dwarfs with planetary systems. However, low…

On the Earth, photosynthetic organisms are responsible for the production of virtually all of the oxygen in the atmosphere. On the land, vegetation reflects in the visible, leading to a red edge that developed about 450 Myr ago and has been…

Oxygen is a well-studied biosignature. Studying potential abiotic pathways for O2 build-up in exoplanet atmospheres is essential for evaluating whether the detection of O2 would constitute a biosignature detection on other worlds. Previous…

The detection of exoplanets orbiting other stars has revolutionized our view of the cosmos. First results suggest that it is teeming with a fascinating diversity of rocky planets, including those in the habitable zone. Even our closest…

Telescope missions are currently being designed which will make direct imaging of habitable exoplanets possible in the near future, and studies are needed to quantify the detectability of biosignature features in the planet's reflectance…

The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. At present, little observational or theoretical basis exists for understanding the ultraviolet…

This chapter reviews proposed exoplanet biosignatures, including their biological origins, observable features, atmospheric sinks, and potentially confounding abiotic sources. Emphasis is placed on material published since past…

Future observations of terrestrial exoplanet atmospheres will occur for planets at different stages of geological evolution. We expect to observe a wide variety of atmospheres and planets with alternative evolutionary paths, with some…

A large number of terrestrial planets in the classical habitable zone of stars of different spectral types has already been discovered and many are expected to be discovered in near future. However, owing to the lack of knowledge on the…