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Rayleigh Scattering in the Atmosphere of the Warm Exo-Neptune GJ 3470b

Dragomir, Diana and Benneke, Björn and Pearson, Kyle A. and Crossfield, Ian J. M. and Eastman, Jason and Barman, Travis and Biddle, Lauren I. (2015) Rayleigh Scattering in the Atmosphere of the Warm Exo-Neptune GJ 3470b. Astrophysical Journal, 814 (2). Art. No. 102. ISSN 0004-637X.

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GJ 3470b is a warm Neptune-size planet transiting an M dwarf star. Like the handful of other small exoplanets for which transmission spectroscopy has been obtained, GJ 3470b exhibits a flat spectrum in the near- and mid-infrared. Recently, a tentative detection of Rayleigh scattering in its atmosphere has been reported. This signal manifests itself as an observed increase of the planetary radius as a function of decreasing wavelength in the visible. We set out to verify this detection and observed several transits of this planet with the LCOGT network and the Kuiper telescope in four different bands (Sloan g, Sloan i, Harris B, and Harris V). Our analysis reveals a strong Rayleigh scattering slope, thus confirming previous results. This makes GJ 3470b the smallest known exoplanet with a detection of Rayleigh scattering. We find that the most plausible scenario is a hydrogen/helium-dominated atmosphere covered by clouds which obscure absorption features in the infrared and hazes which give rise to scattering in the visible. Our results demonstrate the feasibility of exoplanet atmospheric characterization from the ground, even with meter-class telescopes.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Dragomir, Diana0000-0003-2313-467X
Benneke, Björn0000-0001-5578-1498
Crossfield, Ian J. M.0000-0002-1835-1891
Eastman, Jason0000-0003-3773-5142
Barman, Travis0000-0002-7129-3002
Additional Information:© 2015 American Astronomical Society. Received 2015 June 16; accepted 2015 October 20; published 2015 November 20. The authors thank David Ehrenreich, Heather Knutson, Jacob Bean, and Rob Siverd for fruitful discussions. We are grateful to the anonymous referee for suggestions which have led to improvements in the paper. This research makes use of observations from the LCOGT network, and of the SIMBAD database, operated at CDS, Strasbourg, France. I.J.M.C.'s work was performed under a contract with the California Institute of Technology funded by NASA through the Sagan Fellowship Program.
Funding AgencyGrant Number
Subject Keywords:planetary systems; stars: individual (GJ 3470) ; techniques: photometric
Issue or Number:2
Record Number:CaltechAUTHORS:20151222-095221112
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Official Citation:Diana Dragomir et al 2015 ApJ 814 102
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63129
Deposited By: Ruth Sustaita
Deposited On:22 Dec 2015 18:41
Last Modified:11 Oct 2019 23:32

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