Inferring Shallow Surfaces on Sub-Neptune Exoplanets with JWST
نویسندگان
چکیده
Planets smaller than Neptune and larger Earth make up the majority of discovered exoplanets. Those with H$_2$-rich atmospheres are prime targets for atmospheric characterization. The transition between two main classes, super-Earths sub-Neptunes, is not clearly understood as rocky surface likely accessible to observations. Tracking several trace gases (specifically loss ammonia (NH$_3$) hydrogen cyanide (HCN)) has been proposed a proxy presence shallow surface. In this work, we revisit mechanism nitrogen conversion in detail find its timescale on order million years. NH$_3$ exhibits dual paths converting N$_2$ or HCN, depending UV radiation star stage system. addition, methanol (CH$_3$OH) identified robust complementary We follow fiducial example K2-18b 2D photochemical model (VULCAN) an equatorial plane. fairly uniform composition distribution below 0.1 mbar controlled by dayside, result slow chemical evolution. CH$_3$OH concluded be most unambiguous proxies infer surfaces sub-Neptunes era James Webb Space Telescope (JWST).
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ژورنال
عنوان ژورنال: The astrophysical journal
سال: 2021
ISSN: ['2041-8213', '2041-8205']
DOI: https://doi.org/10.3847/2041-8213/ac399a