3.6 AND 4.5<i>μ</i>m PHASE CURVES OF THE HIGHLY IRRADIATED ECCENTRIC HOT JUPITER WASP-14b

Abstract

We present full-orbit phase curve observations of the eccentric ($e\\sim\n0.08$) transiting hot Jupiter WASP-14b obtained in the 3.6 and 4.5 $\\mu$m bands\nusing the \\textit{Spitzer Space Telescope}. We use two different methods for\nremoving the intrapixel sensitivity effect and compare their efficacy in\ndecoupling the instrumental noise. Our measured secondary eclipse depths of\n$0.1882\\%\\pm 0.0048\\%$ and $0.2247\\%\\pm 0.0086\\%$ at 3.6 and 4.5 $\\mu$m,\nrespectively, are both consistent with a blackbody temperature of $2402\\pm 35$\nK. We place a $2\\sigma$ upper limit on the nightside flux at 3.6 $\\mu$m and\nfind it to be $9\\%\\pm 1\\%$ of the dayside flux, corresponding to a brightness\ntemperature of 1079 K. At 4.5 $\\mu$m, the minimum planet flux is $30\\%\\pm 5\\%$\nof the maximum flux, corresponding to a brightness temperature of $1380\\pm 65$\nK. We compare our measured phase curves to the predictions of one-dimensional\nradiative transfer and three-dimensional general circulation models. We find\nthat WASP-14b's measured dayside emission is consistent with a model atmosphere\nwith equilibrium chemistry and a moderate temperature inversion. These same\nmodels tend to over-predict the nightside emission at 3.6 $\\mu$m, while\nunder-predicting the nightside emission at 4.5 $\\mu$m. We propose that this\ndiscrepancy might be explained by an enhanced global C/O ratio. In addition, we\nfind that the phase curves of WASP-14b ($7.8 M_{\\mathrm{Jup}}$) are consistent\nwith a much lower albedo than those of other Jovian mass planets with thermal\nphase curve measurements, suggesting that it may be emitting detectable heat\nfrom the deep atmosphere or interior processes.\n