论文标题
GTC系外行驶光谱调查XI。可能检测土星质量星球WASP-69B大气中的瑞利散射
The GTC exoplanet transit spectroscopy survey XI. Possible detection of Rayleigh scattering in the atmosphere of the Saturn-mass planet WASP-69b
论文作者
论文摘要
瑞利散射是从地面和太空设施中可检测的系外行星大气中的主要大气特征之一。在以氢为主的行星气氛中，瑞利散射导致测得的行星半径在光学范围内朝着蓝色波长增加。我们使用Gran Telescopio Canarias上的Osiris仪器获得了土星质量WASP-69B的一个传输的分光光度度计时间序列。从数据中，我们构建了19个光谱传输曲线，代表20 nm宽的波长bin，跨度从515 nm到905 nm。我们通过将分析模型与高斯工艺拟合，以说明光曲线中的系统噪声，从而得出每个曲线的过境深度。我们发现，过境深度朝着蓝色波长增加，这表明有效行星半径较大。我们的结果与使用哈勃太空望远镜在近红外获得的空间测量结果一致，后者显示了传输光谱的兼容斜率。我们讨论了检测到的斜率的起源，并在两种可能的情况之间进行争论：源自行星大气中的瑞利散射检测或宿主恒星引起的恒星活动引起的信号。
One of the main atmospheric features in exoplanet atmospheres, detectable both from ground- and space-based facilities, is Rayleigh scattering. In hydrogen-dominated planetary atmospheres, Rayleigh scattering causes the measured planetary radius to increase toward blue wavelengths in the optical range. We obtained a spectrophotometric time series of one transit of the Saturn-mass planet WASP-69b using the OSIRIS instrument at the Gran Telescopio Canarias. From the data we constructed 19 spectroscopic transit light curves representing 20 nm wide wavelength bins spanning from 515 nm to 905 nm. We derived the transit depth for each curve individually by fitting an analytical model together with a Gaussian process to account for systematic noise in the light curves. We find that the transit depth increases toward bluer wavelengths, indicative of a larger effective planet radius. Our results are consistent with space-based measurements obtained in the near infrared using the Hubble Space Telescope, which show a compatible slope of the transmission spectrum. We discuss the origin of the detected slope and argue between two possible scenarios: a Rayleigh scattering detection originating in the planet's atmosphere or a stellar activity induced signal from the host star.
