文章基本信息

标题：Diffuser-assisted Photometric Follow-up Observations of the Neptune-sized Planets K2-28b and K2-100b
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作者：Gudmundur Stefansson ; Yiting Li ; Suvrath Mahadevan 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2018
卷号：156
期号：6
页码：1-14
DOI：10.3847/1538-3881/aae6ca
语种：English
出版社：American Institute of Physics
摘要：We present precision transit observations of the Neptune-sized planets K2-28b and K2-100b using the Engineered Diffuser on the Astrophysical Research Council Telescope Imaging Camera (ARCTIC) imager on the ARC 3.5 m Telescope at Apache Point Observatory. K2-28b is a R p =2.56 R ⊕ mini-Neptune transiting a bright (J=11.7) metal-rich M4 dwarf offering compelling prospects for future atmospheric characterization. K2-100b is an R p =3.45 R ⊕ Neptune in the Praesepe Cluster and is one of few planets known in a cluster transiting a host star bright enough (V=10.5) for precision radial velocity observations. Using the precision photometric capabilities of the diffuser/ARCTIC system allows us to achieve a precision of 365 ppm and 70ppm in 30-minute bins for K2-28b and K2-100b, respectively. Our joint-fits to the K2 and ground-based light curves give an order-of-magnitude improvement in the orbital ephemeris for both planets, yielding a timing precision of 2minutes in the James Webb Space Telescope (JWST) era. Although we show that the currently available broad-band measurements of K2-28b’s radius are currently too imprecise to place useful constraints on K2-28b’s atmosphere, we demonstrate that JWST/NIRISS will be able to discern between a cloudy/clear atmosphere in a modest number of transit observations. Our light curve of K2-100b marks the first transit follow-up observation of this challenging-to-observe transit, where we obtain a transit depth of 822±50 ppm in the SDSS i′ band. We conclude that diffuser-assisted photometry can play an important role in the Transiting Exoplanet Survey Satellite (TESS) era to perform timely and precise follow-up of the expected bounty of TESS planet candidates.
关键词：planets and satellites: fundamental parameters;techniques: photometric