A Correlation Between Stellar Activity and Hot Jupiter Emission Spectra
Abstract
We present evidence for a correlation between the observed properties of hot Jupiter emission spectra and the activity levels of the host stars measured using Ca II H & K emission lines. We find that planets with dayside emission spectra that are well-described by standard one-dimensional atmosphere models with water in absorption (HD 189733, TrES-1, TrES-3, WASP-4) orbit chromospherically active stars, while planets with emission spectra that are consistent with the presence of a strong high-altitude temperature inversion and water in emission orbit quieter stars. We estimate that active G and K stars have Lyman α fluxes that are typically a factor of 4-7 times higher than quiet stars with analogous spectral types and propose that the increased UV flux received by planets orbiting active stars destroys the compounds responsible for the formation of the observed temperature inversions. In this paper, we also derive a model-independent method for differentiating between these two atmosphere types using the secondary eclipse depths measured in the 3.6 and 4.5 μm bands on the Spitzer Space Telescope and argue that the observed correlation is independent of the inverted/non-inverted paradigm for classifying hot Jupiter atmospheres.
Additional Information
© 2010 American Astronomical Society. Received 2010 April 14; accepted 2010 July 21; published 2010 August. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by both NASA and the University of California. We thank Geoff Marcy and Debra Fischer for their generous assistance in obtaining the Keck/HIRES spectra and deriving the SME values used in this analysis, as well as Lucianne Walkowicz, Kevin Zahnle, Mark Marley, Jonathan Fortney, Drake Deming, Jean-Michel Desert, and Adam Burrows for providing invaluable commentary on various aspects of this project. H.A.K. is supported by a fellowship from the Miller Institute for Basic Research in Science. We thank the observers who contributed to the data reported here. We gratefully acknowledge the efforts and dedication of the Keck Observatory staff, especially Scott Dahm, Hien Tran, and Grant Hill for support of HIRES and Greg Wirth for support of remote observing. A. W. H. gratefully acknowledges support from a Townes Post-doctoral Fellowship at the U. C. Berkeley Space Sciences Laboratory. Finally, the authors wish to extend special thanks to those of Hawai'ian ancestry on whose sacred mountain of Mauna Kea we are privileged to be guests. Without their generous hospitality, the Keck observations presented herein would not have been possible.Attached Files
Published - 0004-637X_720_2_1569.pdf
Accepted Version - 1004.2702.pdf
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Additional details
- Eprint ID
- 36657
- Resolver ID
- CaltechAUTHORS:20130129-133640941
- Miller Institute for Basic Research in Science
- University of California, Berkeley
- Created
-
2013-01-29Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences