Illusion and reality in the atmospheres of exoplanets
| Autor: | Sara Seager, Drake Deming |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences James Webb Space Telescope Astrophysics::Instrumentation and Methods for Astrophysics Exoplanetology Astronomy 01 natural sciences Earth radius Exoplanet Astrobiology Geophysics Space and Planetary Science Geochemistry and Petrology Planet Neptune Sub-Earth 0103 physical sciences Earth and Planetary Sciences (miscellaneous) Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics 0105 earth and related environmental sciences Discoveries of exoplanets |
| Zdroj: | Journal of Geophysical Research: Planets. 122:53-75 |
| ISSN: | 2169-9097 |
| DOI: | 10.1002/2016je005155 |
| Popis: | The atmospheres of exoplanets reveal all their properties beyond mass, radius, and orbit. Based on bulk densities, we know that exoplanets as small as 1.5 Earth radii must have gaseous envelopes, hence atmospheres. We discuss contemporary techniques for characterization of exoplanetary atmospheres. The measurements are difficult, because - even in current favorable cases - the signals can be as small as 0.001% of the host star's flux. Consequently, some early results have been illusory, and not confirmed by subsequent investigations. Prominent illusions to date include polarized scattered light, temperature inversions, and the existence of carbon planets. The field moves from the first tentative and often incorrect conclusions, converging to the reality of exoplanetary atmospheres. That reality is revealed using transits for close-in exoplanets, and direct imaging for young or massive exoplanets in distant orbits. Several atomic and molecular constituents have now been robustly detected in exoplanets as small as Neptune. In our current observations, the effects of clouds and haze appear ubiquitous. Topics at the current frontier include the measurement of heavy element abundances in giant planets, detection of carbon-based molecules, measurement of atmospheric temperature profiles, definition of heat circulation efficiencies for tidally-locked planets, and the push to detect and characterize the atmospheres of super-Earths. Future observatories for this quest include the James Webb Space Telescope, and the new generation of Extremely Large Telescopes on the ground. On a more distant horizon, NASA's plans for the HabEx and LUVOIR missions could extend the study of exoplanetary atmospheres to true twins of Earth. |
| Databáze: | OpenAIRE |
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