Volume 567, July 2014
|Number of page(s)||8|
|Section||Planets and planetary systems|
|Published online||04 July 2014|
1 Purple Mountain Observatory & Key Laboratory for Radio Astronomy, Chinese Academy of Sciences, 2 West Beijing Road, 210008 Nanjing, PR China
2 University of Chinese Academy of Sciences, 19A Yuquan Road, 100049 Beijing, PR China
3 Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
4 Astrophysics Group, University of Exeter, Stocker Road, EX4 4 QL Exeter, UK
5 Institut für Astrophysik, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
Received: 12 March 2014
Accepted: 22 May 2014
Aims. We aim to construct a spectral energy distribution (SED) for the emission from the dayside atmosphere of the hot Jupiter WASP-46b and to investigate its energy budget.
Methods. We observed a secondary eclipse of WASP-46b simultaneously in the g′r′i′z′JHK bands using the GROND instrument on the MPG/ESO 2.2 m telescope. Eclipse depths of the acquired light curves were derived to infer the brightness temperatures at multibands that cover the SED peak.
Results. We report the first detection of the thermal emission from the dayside of WASP-46b in the K band at 4.2σ level and tentative detections in the H (2.5σ) and J (2.3σ) bands, with flux ratios of 0.253 +0.063-0.060%, 0.194 ± 0.078%, and 0.129 ± 0.055%, respectively. The derived brightness temperatures (2306 +177-187 K, 2462 +245-302 K, and 2453 +198-258 K, respectively) are consistent with an isothermal temperature profile of 2386 K, which is significantly higher than the dayside-averaged equilibrium temperature, indicative of very poor heat redistribution efficiency. We also investigate the tentative detections in the g′r′i′ bands and the 3σ upper limit in the z′ band, which might indicate the existence of reflective clouds if these tentative detections do not arise from systematics.
Key words: stars: individual: WASP-46 / planets and satellites: individual: WASP-46b / planets and satellites: atmospheres / planetary systems / techniques: photometric
Based on observations collected with the Gamma Ray burst Optical and Near-infrared Detector (GROND) on the MPG/ESO 2.2 m telescope at the La Silla Observatory, Chile. Program 088.A-9016 (PI: Chen).
Appendix A is available in electronic form at http://www.aanda.org
Photometric time series are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (18.104.22.168) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A8
© ESO, 2014
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