[Friday Seminar]: Rocky planet or water world? Observability of low-density lava world atmospheres

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• Anjali Piette, Carnegie Institution for Science
• Friday 23 June 2023, 15:00-16:00
• Nuffield G18.

If you have a question about this talk, please contact Lalitha Sairam.

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 high enough to evaporate their surfaces, providing a unique opportunity to probe their interior compositions and test for the presence of volatiles. In this talk, I will discuss the atmospheric observability of low-density lava worlds. I 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 sub-stellar temperatures spanning _{1900-2800 K: HD86226c, HD3167b and 55Cnce. Given the possibility of mixed volatile and silicate interior compositions for these planets, I consider a range of mixed volatile and rock vapor atmospheric compositions. This includes a range of volatile fractions and three volatile compositions: water-rich, water with CO2 , and a desiccated O-rich scenario. I find that spectral features due to H2O , CO2, SiO and SiO2 are present in the infrared emission spectra as either emission or absorption features, depending on dayside temperature, volatile fraction and volatile composition. I further simulate JWST secondary eclipse observations for each of the three case studies, finding that H2O and/or CO2 could be detected with as few as} 5 eclipses. Detecting volatiles in these atmospheres would provide crucial independent evidence that volatile-rich interiors exist among the super-Earth population.

This talk is part of the Astrophysics Talks Series series.

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• Astrophysics Talks Series
• Bham Talks
• Nuffield G18
• What's on in Physics?

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