Sensitivity of Dry Lava Planet Atmospheric Emission Spectra to Changes in Lava Compositions

Fuente: arXiv
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Main Authors: van Buchem, Christiaan P. A., Buddhacharya, Rojita, Zilinskas, Mantas, Zieba, Sebastian, Miguel, Yamila, van Westrenen, Wim
Format: Preprint
Published: 2026
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author van Buchem, Christiaan P. A.
Buddhacharya, Rojita
Zilinskas, Mantas
Zieba, Sebastian
Miguel, Yamila
van Westrenen, Wim
author_facet van Buchem, Christiaan P. A.
Buddhacharya, Rojita
Zilinskas, Mantas
Zieba, Sebastian
Miguel, Yamila
van Westrenen, Wim
contents The atmospheres of hot rocky exoplanets are among the first primary targets of the JWST. Interpreting their atmospheric spectra requires understanding the link between silicate lava compositions and overlying atmospheres. We investigate the sensitivity of simulated emission spectra of dry lava planets to variations in oxide abundances in silicate melt. Our goal is to determine which molten surface features could be distinguishable with future observations. We combine our vaporisation code with gas chemical equilibrium and radiative transfer codes to self-consistently compute atmospheric chemistry and thermal structure. Alongside varying lava compositions, we assess the impact of host star spectral type on emission spectra. TiO2 melt abundance dictates atmospheric TiO, which strongly influences surface temperature and emission spectra due to its short-wave opacity. This creates a degeneracy with heat redistribution efficiency, potentially broken by observing the optical TiO emission feature. Atmospheric SiO and SiO2 abundances depend on melt SiO2 content, with stronger SiO and SiO2 emission features at higher melt abundances. For the currently best observable HREs, changes in TiO2 and SiO2 abundance of about an order of magnitude with respect to BSE, could potentially be observable with 12 JWST eclipse observations.
format Preprint
id arxiv_https___arxiv_org_abs_2604_18301
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Sensitivity of Dry Lava Planet Atmospheric Emission Spectra to Changes in Lava Compositions
van Buchem, Christiaan P. A.
Buddhacharya, Rojita
Zilinskas, Mantas
Zieba, Sebastian
Miguel, Yamila
van Westrenen, Wim
Earth and Planetary Astrophysics
The atmospheres of hot rocky exoplanets are among the first primary targets of the JWST. Interpreting their atmospheric spectra requires understanding the link between silicate lava compositions and overlying atmospheres. We investigate the sensitivity of simulated emission spectra of dry lava planets to variations in oxide abundances in silicate melt. Our goal is to determine which molten surface features could be distinguishable with future observations. We combine our vaporisation code with gas chemical equilibrium and radiative transfer codes to self-consistently compute atmospheric chemistry and thermal structure. Alongside varying lava compositions, we assess the impact of host star spectral type on emission spectra. TiO2 melt abundance dictates atmospheric TiO, which strongly influences surface temperature and emission spectra due to its short-wave opacity. This creates a degeneracy with heat redistribution efficiency, potentially broken by observing the optical TiO emission feature. Atmospheric SiO and SiO2 abundances depend on melt SiO2 content, with stronger SiO and SiO2 emission features at higher melt abundances. For the currently best observable HREs, changes in TiO2 and SiO2 abundance of about an order of magnitude with respect to BSE, could potentially be observable with 12 JWST eclipse observations.
title Sensitivity of Dry Lava Planet Atmospheric Emission Spectra to Changes in Lava Compositions
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2604.18301