论文标题
LRG野兽：地面检测钠和高度膨胀热的Wasp-21b大气中的陡峭斜率
LRG-BEASTS: Ground-based Detection of Sodium and a Steep Optical Slope in the Atmosphere of the Highly Inflated Hot-Saturn WASP-21b
论文作者
论文摘要
我们使用LRG-BEAST望远镜上的ACAM仪器通过LRG-BEASTS调查（低分辨率地面地面外部球星大气调查使用传输光谱），使用三个转移介绍了高度充气的土星质量系外行星WASP-21b的光传输光谱，该光谱频谱使用了三个转运。我们的传输频谱覆盖了4635-9000埃的波长范围，与246ppm的一个大气尺度高度相比，达到197ppm的平均过境深度精度。我们检测到30盎司的bin宽度中的吸收，以> 4 $σ$置信度，它扩展了100埃埃斯特罗姆。我们没有看到来自K I的吸收的证据。散射坡度的大气检索分析表明，对于H $ _2 $的瑞利散射太陡了，但与HD 189733B非常相似。在我们的传输光谱中观察到的特征不能仅由恒星活动引起，而对WASP-21的光度监测表明它是不活跃的恒星。因此，我们得出的结论是，WASP-21b大气中的气溶胶正在引起我们观察到的陡坡，而WASP-21B是限制其大气金属性的红外观测值的绝佳目标。
We present the optical transmission spectrum of the highly inflated Saturn-mass exoplanet WASP-21b, using three transits obtained with the ACAM instrument on the William Herschel Telescope through the LRG-BEASTS survey (Low Resolution Ground-Based Exoplanet Atmosphere Survey using Transmission Spectroscopy). Our transmission spectrum covers a wavelength range of 4635-9000 Angstrom, achieving an average transit depth precision of 197ppm compared to one atmospheric scale height at 246ppm. We detect Na I absorption in a bin width of 30 Angstrom, at >4$σ$ confidence, which extends over 100 Angstrom. We see no evidence of absorption from K I. Atmospheric retrieval analysis of the scattering slope indicates it is too steep for Rayleigh scattering from H$_2$, but is very similar to that of HD 189733b. The features observed in our transmission spectrum cannot be caused by stellar activity alone, with photometric monitoring of WASP-21 showing it to be an inactive star. We therefore conclude that aerosols in the atmosphere of WASP-21b are giving rise to the steep slope that we observe, and that WASP-21b is an excellent target for infra-red observations to constrain its atmospheric metallicity.
