论文标题
幻影还是绿洲？温暖的海王星大气中的水蒸气Toi-674 b
A Mirage or an Oasis? Water Vapor in the Atmosphere of the Warm Neptune TOI-674 b
论文作者
论文摘要
我们报告了最近发现的Neptune Toi-674 B（5.25 \ hareftth {}，23.6 \ Mearth {}）的观察结果，该观察是Hubble Space Telescope的宽场摄像头3仪器。 TOI-674 b在海王星沙漠中，在短轨道时期观察到的海王星大小的系外行星的匮乏。由于光蒸发质量损失或轨道迁移，沙漠中的行星被认为具有复杂的进化史，从而确定其大气成分对于理解其起源至关重要。我们用G141 Grism获得了行星大气的近红外传播光谱。在提取，下降和拟合光谱灯曲面以测量行星的传播光谱后，我们使用Petitradtrans大气光谱合成代码在地球的大气中进行检索，以识别存在哪些吸收剂。这些结果表明，由于水蒸气为2.9 $σ$（贝叶斯因子= 15.8），在1.4 $ $ $ m时的吸收中有中度证据，以及在2.2 $σ$（贝叶斯因子= 4.0）中存在云的弱证据。 TOI-674 B是进一步研究的有力候选者，以完善水丰度，这受我们的数据限制。我们还合并了新的苔丝短体光学光度法以及Spitzer/IRAC数据，并重新构建了行星的过境参数。我们发现行星具有以下过境参数：$ r_p/r_* = 0.1135 \ pm0.0006 $，$ t_0 = 2458544.523792 \ pm0.000452 $ bjd和$ p = 1.977198 \ pM0.007 $ d。这些测量值优化了行星半径估计值，并改善了轨道上的闪烁体，以对这种高度吸引人的温暖海王星进行未来的过境光谱观测。
We report observations of the recently discovered warm Neptune TOI-674 b (5.25 \rearth{}, 23.6 \mearth{}) with the Hubble Space Telescope's Wide Field Camera 3 instrument. TOI-674 b is in the Neptune desert, an observed paucity of Neptune-size exoplanets at short orbital periods. Planets in the desert are thought to have complex evolutionary histories due to photoevaporative mass loss or orbital migration, making identifying the constituents of their atmospheres critical to understanding their origins. We obtained near-infrared transmission spectroscopy of the planet's atmosphere with the G141 grism. After extracting, detrending, and fitting the spectral lightcurves to measure the planet's transmission spectrum, we used the petitRADTRANS atmospheric spectral synthesis code to perform retrievals on the planet's atmosphere to identify which absorbers are present. These results show moderate evidence for increased absorption at 1.4 $μ$m due to water vapor at 2.9$σ$ (Bayes factor = 15.8), as well as weak evidence for the presence of clouds at 2.2$σ$ (Bayes factor = 4.0). TOI-674 b is a strong candidate for further study to refine the water abundance, which is poorly constrained by our data. We also incorporated new TESS short-cadence optical photometry, as well as Spitzer/IRAC data, and re-fit the transit parameters for the planet. We find the planet to have the following transit parameters: $R_p/R_* = 0.1135\pm0.0006$, $T_0 = 2458544.523792\pm0.000452$ BJD, and $P = 1.977198\pm0.00007$ d. These measurements refine the planet radius estimate and improve the orbital ephemerides for future transit spectroscopy observations of this highly intriguing warm Neptune.
