DETECTION OF H2O AND EVIDENCE FOR TiO/VO IN AN ULTRA-HOT EXOPLANET ATMOSPHERE

被引:160
作者
Evans, Thomas M. [1 ]
Sing, David K. [1 ]
Wakeford, Hannah R. [2 ]
Nikolov, Nikolay [1 ]
Ballester, Gilda E. [3 ]
Drummond, Benjamin [1 ]
Kataria, Tiffany [1 ]
Gibson, Neale P. [4 ]
Amundsen, David S. [5 ,6 ]
Spake, Jessica [1 ]
机构
[1] Univ Exeter, Sch Phys, Exeter EX4 4QL, Devon, England
[2] NASA Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
[3] Univ Arizona, Lunar & Planetary Lab, Tucson, AZ 85721 USA
[4] Queens Univ Belfast, Sch Math & Phys, Astrophys Res Ctr, Belfast BT7 1NN, Antrim, North Ireland
[5] Columbia Univ, Dept Appl Phys & Appl Math, New York, NY 10025 USA
[6] NASA Goddard Inst Space Studies, New York, NY 10025 USA
基金
欧洲研究理事会;
关键词
planets and satellites: atmospheres; stars: individual (WASP-121); techniques: photometric; techniques: spectroscopic; TRANSMISSION SPECTRAL SURVEY; HUBBLE-SPACE-TELESCOPE; GIANT PLANET ATMOSPHERES; LIMB-DARKENING LAW; OR-EQUAL-TO; EXTRASOLAR PLANET; BROWN DWARF; HD; 209458B; IRRADIATED ATMOSPHERES; SURFACE GRAVITIES;
D O I
10.3847/2041-8205/822/1/L4
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present a primary transit observation for the ultra-hot (T-eq similar to 2400 K) gas giant expolanet WASP-121b, made using the Hubble Space Telescope Wide Field Camera 3 in spectroscopic mode across the 1.12-1.64 mu m wavelength range. The 1.4 mu m water absorption band is detected at high confidence (5.4 sigma) in the planetary atmosphere. We also reanalyze ground-based photometric light curves taken in the B, r', and z' filters. Significantly deeper transits are measured in these optical bandpasses relative to the near-infrared wavelengths. We conclude that scattering by high-altitude haze alone is unlikely to account for this difference and instead interpret it as evidence for titanium oxide and vanadium oxide absorption. Enhanced opacity is also inferred across the 1.12-1.3 mu m wavelength range, possibly due to iron hydride absorption. If confirmed, WASP-121b will be the first exoplanet with titanium oxide, vanadium oxide, and iron hydride detected in transmission. The latter are important species in M/L dwarfs and their presence is likely to have a significant effect on the overall physics and chemistry of the atmosphere, including the production of a strong thermal inversion.
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页数:7
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