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The Hubble Space Telescope PanCET Program: Exospheric Mg ii and Fe ii in the Near-ultraviolet Transmission Spectrum of WASP-121b Using Jitter Decorrelation
- Source :
- Astronomical Journal, Astronomical Journal, American Astronomical Society, 2019, 158 (2), pp.91. ⟨10.3847/1538-3881/ab2986⟩, The Astronomical Journal, The Astronomical Journal, American Astronomical Society, 2019, 158 (2), pp.91. ⟨10.3847/1538-3881/ab2986⟩, Sing, D K, Lavvas, P, Ballester, G E, des Etangs, A L, Marley, M S, Nikolov, N, Ben-Jaffel, L, Bourrier, V, Buchhave, L A, Deming, D L, Ehrenreich, D, Mikal-Evans, T, Kataria, T, Lewis, N K, Lopez-Morales, M, Munoz, A G, Henry, G W, Sanz-Forcada, J, Spake, J J & Wakeford, H R 2019, ' The Hubble Space Telescope PanCET Program: Exospheric Mg II and Fe II in the Near-ultraviolet Transmission Spectrum of WASP-121b Using Jitter Decorrelation ', Astronomical Journal, vol. 158, no. 2, 91 . https://doi.org/10.3847/1538-3881/ab2986
- Publication Year :
- 2019
- Publisher :
- HAL CCSD, 2019.
-
Abstract
- We present Hubble Space Telescope (HST) near-ultraviolet (NUV) transits of the hot Jupiter WASP-121b, acquired as part of the PanCET program. Time-series spectra during two transit events were used to measure the transmission spectra between 2280 and 3070 Å at a resolution of 30,000. Using HST data from 61 Space Telescope Imaging Spectrograph visits, we show that data from HST's Pointing Control System can be used to decorrelate the instrument systematic errors (jitter decorrelation), which we used to fit the WASP-121b light curves. The NUV spectra show very strong absorption features, with the NUV white light curve found to be larger than the average optical and near-infrared value at 6σ confidence. We identify and spectrally resolve absorption from the Mg ii doublet in the planetary exosphere at a 5.9σ confidence level. The Mg ii doublet is observed to reach altitudes of R pl/R star = 0.284 ± 0.037 for the 2796 Å line and 0.242 ± 0.0431 for the 2804 Å line, which exceeds the Roche lobe size as viewed in transit geometry (R eqRL/R star = 0.158). We also detect and resolve strong features of the Fe ii UV1 and UV2 multiplets, and observe the lines reaching altitudes of R pl/R star ≈ 0.3. At these high altitudes, the atmospheric Mg ii and Fe ii gas is not gravitationally bound to the planet, and these ionized species may be hydrodynamically escaping or could be magnetically confined. Refractory Mg and Fe atoms at high altitudes also indicate that these species are not trapped into condensate clouds at depth, which places constraints on the deep interior temperature.
- Subjects :
- 010504 meteorology & atmospheric sciences
[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP]
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
Spectral line
spectroscopic [Techniques]
Planet
0103 physical sciences
Hot Jupiter
Astrophysics::Solar and Stellar Astrophysics
Roche lobe
Absorption (logic)
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
ComputingMilieux_MISCELLANEOUS
0105 earth and related environmental sciences
Line (formation)
Physics
planets and satellites: atmospheres
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]
photometric [Techniques]
Astronomy and Astrophysics
Light curve
techniques photometric
individual (WASP-121) [Stars]
13. Climate action
Space and Planetary Science
atmospheres [Planets and satellites]
Astrophysics::Earth and Planetary Astrophysics
techniques: spectroscopic
Exosphere
stars: individual (WASP-121)
Subjects
Details
- Language :
- English
- ISSN :
- 00046256, 15383881, 0004637X, and 15383873
- Database :
- OpenAIRE
- Journal :
- Astronomical Journal, Astronomical Journal, American Astronomical Society, 2019, 158 (2), pp.91. ⟨10.3847/1538-3881/ab2986⟩, The Astronomical Journal, The Astronomical Journal, American Astronomical Society, 2019, 158 (2), pp.91. ⟨10.3847/1538-3881/ab2986⟩, Sing, D K, Lavvas, P, Ballester, G E, des Etangs, A L, Marley, M S, Nikolov, N, Ben-Jaffel, L, Bourrier, V, Buchhave, L A, Deming, D L, Ehrenreich, D, Mikal-Evans, T, Kataria, T, Lewis, N K, Lopez-Morales, M, Munoz, A G, Henry, G W, Sanz-Forcada, J, Spake, J J & Wakeford, H R 2019, ' The Hubble Space Telescope PanCET Program: Exospheric Mg II and Fe II in the Near-ultraviolet Transmission Spectrum of WASP-121b Using Jitter Decorrelation ', Astronomical Journal, vol. 158, no. 2, 91 . https://doi.org/10.3847/1538-3881/ab2986
- Accession number :
- edsair.doi.dedup.....e799b18c5c9ab42a7cc9a1a63f2e05da