Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b
Hubble Space Telescope hot Jupiter transmission spectral survey: a detection of Na and strong optical absorption in HAT-P-1b
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DOI：
10.1093/mnras/stt1859
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发表时间：
2013-09
影响因子：
4.8
通讯作者：
N. Nikolov;D. Sing;F. Pont;A. Burrows;J. Fortney;G. Ballester;T. Evans;C. Huitson;H. Wakeford;P. Wilson;S. Aigrain;D. Deming;N. Gibson;G. Henry;H. Knutson;A. D. Étangs;A. Showman;A. Vidal-Madjar;K. Zahnle
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作者：
N. Nikolov;D. Sing;F. Pont;A. Burrows;J. Fortney;G. Ballester;T. Evans;C. Huitson;H. Wakeford;P. Wilson;S. Aigrain;D. Deming;N. Gibson;G. Henry;H. Knutson;A. D. Étangs;A. Showman;A. Vidal-Madjar;K. Zahnle
基于哈勃太空望远镜的观测，利用空间望远镜成像光谱仪（STIS），结合最近的宽视场相机3 （WFC3）凌日（1.087 ~ 1.687 μm），绘制了热木星HAT-P-1b的光学到近红外透射光谱，覆盖了0.29 ~ 1.027 μm的光谱范围。我们得到了HAT-P-1系统的精细化物理参数，包括改进的轨道星历。透射光谱在0.55 μm处有较强的吸收特征，在近紫外波段有较强的向蓝斜率。我们检测到大气钠吸收在3.3σ显著水平，但没有发现钾特征的证据。红色数据表明，在波长大于~ 0.85 μm时，光谱略微平坦，吸收增强。STIS和WFC3光谱在绝对半径水平（4.3±1.6压力标度高度）上差异显著，表明HAT-P-1b在大气中有很强的光吸收。光学和近红外的差异不能用恒星活动来解释，因为同时对G0V HAT-P-1b主星及其相同伴星的恒星活动监测显示，没有显著的活动可以解释这一结果。我们将完整的sts和WFC3传输光谱与包含雾霾、钠和额外光学吸收剂的理论大气模型进行了比较。我们发现光学吸收剂和超级太阳钠水丰度比可能是解释HAT-P-1b观测结果的一个场景。我们的研究结果表明，在一些热木星系外行星中，强光学吸收体可能是主要的大气特征。
We present an optical to near-infrared transmission spectrum of the hot Jupiter HAT-P-1b, based on Hubble Space Telescope observations, covering the spectral regime from 0.29 to 1.027 μm with Space Telescope Imaging Spectrograph (STIS), which is coupled with a recent Wide Field Camera 3 (WFC3) transit (1.087 to 1.687 μm). We derive refined physical parameters of the HAT-P-1 system, including an improved orbital ephemeris. The transmission spectrum shows a strong absorption signature shortward of 0.55 μm, with a strong blueward slope into the near-ultraviolet. We detect atmospheric sodium absorption at a 3.3σ significance level, but find no evidence for the potassium feature. The red data imply a marginally flat spectrum with a tentative absorption enhancement at wavelength longer than ∼0.85 μm. The STIS and WFC3 spectra differ significantly in absolute radius level (4.3 ± 1.6 pressure scaleheights), implying strong optical absorption in the atmosphere of HAT-P-1b. The optical to near-infrared difference cannot be explained by stellar activity, as simultaneous stellar activity monitoring of the G0V HAT-P-1b host star and its identical companion show no significant activity that could explain the result. We compare the complete STIS and WFC3 transmission spectrum with theoretical atmospheric models which include haze, sodium and an extra optical absorber. We find that both an optical absorber and a supersolar sodium to water abundance ratio might be a scenario explaining the HAT-P-1b observations. Our results suggest that strong optical absorbers may be a dominant atmospheric feature in some hot Jupiter exoplanets.