Climate change in hell
- Author(s)
- E. Gaidos, H. Parviainen, E. Esparza-Borges, A. Fukui, K. Isogai, K. Kawauchi, J. De Leon, M. Mori, F. Murgas, N. Narita, E. Palle, N. Watanabe
- Abstract
Context. Rocky planets on ultra-short period orbits can have surface magma oceans and rock-vapour atmospheres in which dust can condense. Observations of that dust can inform us about the composition and surface conditions on these objects. Aims. We constrained the properties and long-term (decade) behaviour of the transiting dust cloud from the evaporating planet K2-22b. Methods.We observed K2-22b around 40 predicted transits with MuSCAT ground-based multi-optical channel imagers, and complemented these data with long-term monitoring by the ground-based ATLAS (2018-2024) and space-based TESS (2021-2023) surveys. Results. We detected signals during 7 transits, none of which showed significant wavelength dependence. The expected number of MuSCAT-detected transits is ≥22, indicating a decline in mean transit depth since the K2 discovery observations in 2014. Conclusions. The lack of a significant wavelength dependence indicates that dust grains are large or the cloud is optically thick. Long-term trends of depth could be due to a magnetic cycle on the host star or to overturn of the planet's dayside surface magma ocean. The possibility that K2-22b is disappearing altogether is ruled out by the stability of the transit ephemeris against non-gravitational forces, which constrains the mass to be at least comparable to Ceres.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- University of Hawaii at Manoa, University of La Laguna, Institute of Astrophysics of the Canary Islands, University of Tokyo, Kyoto University, Ritsumeikan University, National Astronomical Observatory of Japan
- Journal
- Astronomy and Astrophysics
- Volume
- 688
- No. of pages
- 9
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361/202451332
- Publication date
- 08-2024
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy, 103004 Astrophysics
- Keywords
- ASJC Scopus subject areas
- Astronomy and Astrophysics, Space and Planetary Science
- Sustainable Development Goals
- SDG 13 - Climate Action
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/bb9ea3c9-a24e-4ee5-8b99-4f24479d84cf