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Modelling the atmosphere of lava planet K2-141b: implications for low and high resolution spectroscopy
- Publication Year :
- 2020
-
Abstract
- Transit searches have uncovered Earth-size planets orbiting so close to their host star that their surface should be molten, so-called lava planets. We present idealized simulations of the atmosphere of lava planet K2-141b and calculate the return flow of material via circulation in the magma ocean. We then compare how pure Na, SiO, or SiO$_2$ atmospheres would impact future observations. The more volatile Na atmosphere is thickest followed by SiO and SiO$_2$, as expected. Despite its low vapour pressure, we find that a SiO$_2$ atmosphere is easier to observe via transit spectroscopy due to its greater scale height near the day-night terminator and the planetary radial velocity and acceleration are very high, facilitating high dispersion spectroscopy. The special geometry that arises from very small orbits allows for a wide range of limb observations for K2-141b. After determining the magma ocean depth, we infer that the ocean circulation required for SiO steady-state flow is only $10^{-4}$ m/s while the equivalent return flow for Na is several orders of magnitude greater. This suggests that a steady-state Na atmosphere cannot be sustained and that the surface will evolve over time.<br />Comment: 8 pages, 7 figures
- Subjects :
- Astrophysics - Earth and Planetary Astrophysics
Physics - Space Physics
Subjects
Details
- Database :
- arXiv
- Publication Type :
- Report
- Accession number :
- edsarx.2010.14101
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1093/mnras/staa2487