Exoplanet atmospheres

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Stormy water on Mars: The distribution and saturation of atmospheric water during the dusty season

Science American Association for the Advancement of Science (AAAS) (2020) eaay9522-eaay9522

Authors:

Anna A Fedorova, Franck Montmessin, Oleg Korablev, Mikhail Luginin, Alexander Trokhimovskiy, Denis A Belyaev, Nikolay I Ignatiev, Franck Lefèvre, Juan Alday, Patrick GJ Irwin, Kevin S Olsen, Jean-Loup Bertaux, Ehouarn Millour, Anni Määttänen, Alexey Shakun, Alexey V Grigoriev, Andrey Patrakeev, Svyatoslav Korsa, Nikita Kokonkov, Lucio Baggio, Francois Forget, Colin F Wilson

Abstract:

The loss of water from Mars to space is thought to result from the transport of water to the upper atmosphere, where it is dissociated to hydrogen and escapes the planet. Recent observations have suggested large, rapid seasonal intrusions of water into the upper atmosphere, boosting the hydrogen abundance. We use the Atmospheric Chemistry Suite on the ExoMars Trace Gas Orbiter to characterize the water distribution by altitude. Water profiles during the 2018–2019 southern spring and summer stormy seasons show that high-altitude water is preferentially supplied close to perihelion, and supersaturation occurs even when clouds are present. This implies that the potential for water to escape from Mars is higher than previously thought.
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Evidence for H2 dissociation and recombination heat transport in the atmosphere of KELT-9b

Astrophysical Journal Letters American Astronomical Society 888:2 (2020) L15

Authors:

M Mansfield, JL Bean, KB Stevenson, TD Komacek, TJ Bell, Xianyu Tan, M Malik, TG Beatty, I Wong, NB Cowan, L Dang, J-M Désert, JJ Fortney, BS Gaudi, D Keating, EM-R Kempton, L Kreidberg, V Parmentier, KG Stassun
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Detection of Ionized Calcium in the Atmosphere of the Ultra-hot Jupiter KELT-9b

The Astrophysical Journal Letters American Astronomical Society 888:1 (2020) l13

Authors:

Jake D Turner, Ernst JW de Mooij, Ray Jayawardhana, Mitchell E Young, Luca Fossati, Tommi Koskinen, Joshua D Lothringer, Raine Karjalainen, Marie Karjalainen
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HARMONI - first light spectroscopy for the ELT: spectrograph camera lens mounts

Proceedings of SPIE - The International Society for Optical Engineering SPIE 11451 (2020)

Authors:

A Hidalgo, J Kariuki, J Lynn, W Cheng, A Lowe, Ft Bagci, F Clarke, I Lewis, I Tosh, H Schnetler, J Capone, M Tecza, M Booth, M Rodrigues, N Cann, N Thatte, Z Ozer, T Foster

Abstract:

HARMONI is the first light visible and near-infrared (NIR) integral field spectrograph for the Extremely Large Telescope(ELT). The HARMONI spectrograph will have four near-infrared cameras and two visible, both with seven lenses of various materials and diameters ranging from 286 to 152 mm. The lens mounts design has been optimized for each lens material to compensate for thermal stresses and maintain lens alignment at the operational temperature of 130 K. We discuss their design and mounting concept, as well as assembly and verification steps. We show initial results from two prototypes and outline improvements in the mounting procedures to reach tighter lens alignments. To conclude, we present a description of our future work to measure the decentering of the lenses when cooled down and settled.
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HARMONI: First light spectroscopy for the ELT: Final design and assembly plan of the spectrographs

Proceedings of SPIE - The International Society for Optical Engineering SPIE 11447 (2020)

Authors:

Z Ozer, H Schnetler, Ft Bagci, M Booth, M Brock, N Cann, J Capone, Jc Ortiz, G Dalton, N Dobson, T Foster, Ah Valadez, J Kariuki, I Lewis, A Lowe, J Lynn, M Rodrigues, I Tosh, F Clarke, M Tecza, N Thatte

Abstract:

HARMONI is the first light visible and near-IR integral field spectrograph for the ELT. It covers a large spectral range from 450nm to 2450nm with resolving powers from R (≡λ/Δλ) 3500 to 18000 and spatial sampling from 60mas to 4mas. It can operate in two Adaptive Optics modes - SCAO (including a High Contrast capability) and LTAO - or with NOAO. The project is preparing for Final Design Reviews. The instrument uses a field splitter and image slicer to divide the field into 4 sub-units, each providing an input slit to one of four nearly identical spectrographs. This proceeding presents the final opto-mechanical design and the AIV plan of the spectrograph units.
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