Snellen Ignas A G, de Mooij Ernst J W, Albrecht Simon
Leiden Observatory, Leiden University, Postbus 9513, 2300 RA Leiden, The Netherlands.
Nature. 2009 May 28;459(7246):543-5. doi: 10.1038/nature08045.
Hot Jupiters are a class of extrasolar planet that orbit their parent stars at very short distances. They are expected to be tidally locked, which can lead to a large temperature difference between their daysides and nightsides. Infrared observations of eclipsing systems have yielded dayside temperatures for a number of transiting planets. The day-night contrast of the transiting extrasolar planet HD 189733b was 'mapped' using infrared observations. It is expected that the contrast between the daysides and nightsides of hot Jupiters is much higher at visual wavelengths, shorter than that of the peak emission, and could be further enhanced by reflected stellar light. Here we report the analysis of optical photometric data obtained over 36 planetary orbits of the transiting hot Jupiter CoRoT-1b. The data are consistent with the nightside hemisphere of the planet being entirely black, with the dayside flux dominating the optical phase curve. This means that at optical wavelengths the planet's phase variation is just as we see it for the interior planets in the Solar System. The data allow for only a small fraction of reflected light, corresponding to a geometric albedo of <0.20.
热木星是一类太阳系外行星，它们在非常短的距离内围绕其母恒星运行。预计它们会被潮汐锁定，这可能导致其昼侧和夜侧之间存在很大的温差。对食双星系统的红外观测已经得出了一些凌日行星的昼侧温度。利用红外观测“绘制”了凌日太阳系外行星HD 189733b的昼夜对比度。预计在视觉波长下，热木星的昼侧和夜侧之间的对比度要比峰值发射波长下的对比度高得多，并且可能会因恒星的反射光而进一步增强。在此，我们报告了对凌日热木星CoRoT-1b在36个行星轨道上获得的光学光度数据的分析。数据表明，该行星的夜侧半球完全呈黑色，昼侧通量主导了光学相位曲线。这意味着在光学波长下，该行星的相位变化与我们在太阳系内行星上看到的情况相同。这些数据仅允许有一小部分反射光，对应的几何反照率小于0.20。
