一颗超级地球穿越一颗肉眼可见的恒星
A Super-Earth Transiting a Naked-Eye Star
摘要：
基于MOST太空望远镜两周几乎连续的光度监测，我们已经探测到了最里面的行星“e”绕55 Cnc（V=6.0）运行的凌日。凌日的周期（0.74 d）和相位与Dawson & Fabrycky预测的一致，并且与热的超级地球穿越类太阳恒星的预期持续时间和深度一致。假设恒星的质量和半径为0.963_{-0.029}^{+0.051} M_sun和0.943 +/- 0.010 R_sun，则行星的质量、半径和平均密度分别为8.63 +/- 0.35 Mearth、2.00 +/- 0.14 Rearth和5.9_{-1.1}^{+1.5} g/cm^3。平均密度与地球相当，尽管55 Cnc e内部的质量更大，因此压缩更大。这意味着岩石-铁的成分由大量的水、气体或其他轻元素补充。在凌日之外，我们检测到一个正弦信号，类似于由于行星照明相位变化而产生的预期信号，但全范围（168 +/- 70 ppm）太大，无法反射光或热发射。这个信号没有直接的解释，应该通过进一步的观察来检查。55 Cnc e的主星比任何其他已知的凌日行星都要亮，这将有助于未来的研究。
英文摘要：
We have detected transits of the innermost planet "e" orbiting 55 Cnc (V=6.0), based on two weeks of nearly continuous photometric monitoring with the MOST space telescope. The transits occur with the period (0.74 d) and phase that had been predicted by Dawson & Fabrycky, and with the expected duration and depth for the crossing of a Sun-like star by a hot super-Earth. Assuming the star's mass and radius to be 0.963_{-0.029}^{+0.051} M_sun and 0.943 +/- 0.010 R_sun, the planet's mass, radius, and mean density are 8.63 +/- 0.35 Mearth, 2.00 +/- 0.14 Rearth, and 5.9_{-1.1}^{+1.5} g/cm^3. The mean density is comparable to that of Earth, despite the greater mass and consequently greater compression of the interior of 55 Cnc e. This suggests a rock-iron composition supplemented by a significant mass of water, gas, or other light elements. Outside of transits, we detected a sinusoidal signal resembling the expected signal due to the changing illuminated phase of the planet, but with a full range (168 +/- 70 ppm) too large to be reflected light or thermal emission. This signal has no straightforward interpretation and should be checked with further observations. The host star of 55 Cnc e is brighter than that of any other known transiting planet, which will facilitate future investigations.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
