热木星高清209458b的Cheops几何反照率

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热木星高清209458b的Cheops几何反照率

CHEOPS geometric albedo of the hot Jupiter HD 209458b

论文作者

Brandeker, A., Heng, K., Lendl, M., Patel, J. A., Morris, B. M., Broeg, C., Guterman, P., Beck, M., Maxted, P. F. L., Demangeon, O., Delrez, L., Demory, B. -O., Kitzmann, D., Santos, N. C., Singh, V., Alibert, Y., Alonso, R., Anglada, G., Bárczy, T., Navascues, D. Barrado y, Barros, S. C. C., Baumjohann, W., Beck, T., Benz, W., Billot, N., Bonfils, X., Bruno, G., Cabrera, J., Charnoz, S., Cameron, A. Collier, van Damme, C. Corral, Csizmadia, Sz., Davies, M. B., Deleuil, M., Deline, A., Ehrenreich, D., Erikson, A., Farinato, J., Fortier, A., Fossati, L., Fridlund, M., Gandolfi, D., Gillon, M., Güdel, M., Hoyer, S., Isaak, K. G., Kiss, L., Laskar, J., Etangs, A. Lecavelier des, Lovis, C., Luntzer, A., Magrin, D., Nascimbeni, V., Olofsson, G., Ottensamer, R., Pagano, I., Pallé, E., Peter, G., Piotto, G., Pollacco, D., Queloz, D., Ragazzoni, R., Rando, N., Rauer, H., Ribas, I., Scandariato, G., Ségransan, D., Simon, A. E., Smith, A. M. S., Sousa, S. G., Steller, M., Szabó, Gy. M., Thomas, N., Udry, S., Van Grootel, V., Walton, N., Wolter, D.

论文摘要

我们使用Cheops太空望远镜在光学/可见光中报告了热木星HD 209458B的次要食物的检测。我们对20.4 +/- 3.3 ppm的测量转化为A_G = 0.096 +/- 0.016的几何反照率。先前估计的日期温度约为1500 k，这意味着我们的几何反照率测量主要由反射的星光组成，并且在很大程度上未经热发射的污染。这使得当前结果成为任何系外行星的A_G最强大的测量之一。我们对带通综合的几何反照率的计算表明，A_G的测量值与无云的气氛一致，在这种气氛中，氢分子通过雷利散射反射的星光，水和钠丰度与明星金属性一致。我们预测，带通的苔丝几何反照率太微弱，无法检测到，如果大气确实不含云，则观察到的Cheops观察到的HD 209458B相位曲线将具有与雷利散射相关的明显形状。

We report the detection of the secondary eclipse of the hot Jupiter HD 209458b in optical/visible light using the CHEOPS space telescope. Our measurement of 20.4 +/- 3.3 ppm translates into a geometric albedo of A_g = 0.096 +/- 0.016. The previously estimated dayside temperature of about 1500 K implies that our geometric albedo measurement consists predominantly of reflected starlight and is largely uncontaminated by thermal emission. This makes the present result one of the most robust measurements of A_g for any exoplanet. Our calculations of the bandpass-integrated geometric albedo demonstrate that the measured value of A_g is consistent with a cloud-free atmosphere, where starlight is reflected via Rayleigh scattering by hydrogen molecules, and the water and sodium abundances are consistent with stellar metallicity. We predict that the bandpass-integrated TESS geometric albedo is too faint to detect and that a phase curve of HD 209458b observed by CHEOPS would have a distinct shape associated with Rayleigh scattering if the atmosphere is indeed cloud free.

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