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Rocky Planet or Water World? Observability of Low-density Lava World Atmospheres
- Source :
- The Astrophysical Journal, Vol 954, Iss 1, p 29 (2023)
- Publication Year :
- 2023
- Publisher :
- IOP Publishing, 2023.
-
Abstract
- Super-Earths span a wide range of bulk densities, indicating a diversity in interior conditions beyond that seen in the solar system. In particular, an emerging population of low-density super-Earths may be explained by volatile-rich interiors. Among these, low-density lava worlds have dayside temperatures that are high enough to evaporate their surfaces, providing a unique opportunity to probe their interior compositions and test for the presence of volatiles. In this work, we investigate the atmospheric observability of low-density lava worlds. We use a radiative-convective model to explore the atmospheric structures and emission spectra of these planets, focusing on three case studies with high observability metrics and substellar temperatures spanning ∼1900–2800 K: HD 86226 c, HD 3167 b, and 55 Cnc e. Given the possibility of mixed volatile and silicate interior compositions for these planets, we consider a range of mixed volatile and rock-vapor atmospheric compositions. This includes a range of volatile fractions and three volatile compositions: water-rich (100% H _2 O), water with CO _2 (80% H _2 O+20% CO _2 ), and a desiccated O-rich scenario (67% O _2 +33% CO _2 ). We find that spectral features due to H _2 O, CO _2 , SiO, and SiO _2 are present in the infrared emission spectra as either emission or absorption features, depending on dayside temperature, volatile fraction, and volatile composition. We further simulate JWST secondary-eclipse observations for each of the three case studies, finding that H _2 O and/or CO _2 could be detected with as few as ∼five eclipses. Detecting volatiles in these atmospheres would provide crucial independent evidence that volatile-rich interiors exist among the super-Earth population.
Details
- Language :
- English
- ISSN :
- 15384357
- Volume :
- 954
- Issue :
- 1
- Database :
- Directory of Open Access Journals
- Journal :
- The Astrophysical Journal
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.69105a2e1a548ec88ec150a6948a7b3
- Document Type :
- article
- Full Text :
- https://doi.org/10.3847/1538-4357/acdef2