The extended chromosphere of CoRoT-2A. Discovery and analysis of the chromospheric Rossiter-McLaughlin effect
Abstract
The young G7V dwarf CoRoT-2A is transited by a hot Jupiter and among the most active planet host-stars known to date. We report on the first detection of a chromospheric Rossiter-McLaughlin effect observed in the Ca ii H and K emission-line cores. In Ca ii H and K, the transit lasts 15% longer than that observed in visual photometry, indicating that chromospheric emission extends 100 000 km beyond the photosphere. Our analysis is based on a time series of high-resolution UVES spectra obtained during a planetary transit and simultaneously obtained photometry observed with one of the PROMPT telescopes. The chromospheric Rossiter-McLaughlin effect provides a new tool to spatially resolve the chromospheres of active planet host-stars.
Based on observations obtained with UVES at the ESO VLT Kueyen telescope (program ID 385.D-0426).- Publication:
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Astronomy and Astrophysics
- Pub Date:
- March 2012
- DOI:
- 10.1051/0004-6361/201118042
- Bibcode:
- 2012A&A...539A.150C
- Keywords:
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- stars: individual: CoRoT-2A;
- planetary systems;
- stars: late-type