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Exploring the Plurality of New Worlds: Their Origins, Climate and Habitability

Periodic Reporting for period 3 - EXO-ATMOS (Exploring the Plurality of New Worlds: Their Origins, Climate and Habitability)

Reporting period: 2019-03-01 to 2020-08-31

"The aim of this proposal is to leverage exoplanet detections, as well as observational capabilities and theoretical frameworks, to deepen and broaden our understanding of planetary physics. This project will transform the field of exoplanet atmospheres by contributing to three major advances. We will: i) push exoplanet characterization new frontiers by providing the largest in-depth study of atmospheres through the measurements of precise spectra, and the retrieval of their composition, in order to constrain their origins; ii) reveal for the first time global exo-climate through a novel method to probe atmospheric structure and dynamics; and iii) pioneer an innovative approach that uses robotic small telescopes to estimate the impact of stellar radiation on atmospheres, with a particular focus on their habitability. Theses objectives will be achieved via an ambitious portfolio of cutting-edge observations, combined with state-of-the-art modelling for their interpretation. Their accomplishment would be a major breakthrough, culminating in a comprehensive comparative exoplanetology, which in turn will open up new key discoveries in planetary formation and evolution. Our expertise will also enable predictions on conditions for habitability and direct the search atmospheric biosignatures with upcoming capabilities. The impact of our discoveries will go well beyond the scientific community since the quest of our origins is of interest to mankind.

The proposal is composed of three Research Programmes (RPs), each containing three Work Pakages (WPs):
Research Programme #1 (RP1): Obtaining exoplanets’ spectra to derive their composition and origins.
Research Programme #2 (RP2): Atmospheric dynamics and climates of close-in exoplanets
Research Programme #3 (RP3): Stellar hosts activity and its impact on atmospheres and habitability
We provide below a description of the work carried out during the reporting period (ERC mid-term) towards the achievement of each listed objectives in the proposal.

RP1: My group contributed to constrain the origins of close-in giant exoplanets through the study of their atmospheric properties, by making progress on the GMOS project, the observation of WAPS-18b with HST/WFC3, and the Spitzer Science Exploration observations. The first paper for the GMOS survey is published (Huitson, Desert et al., 2017) and more papers are coming on this topic (Desert et al. in prep, Todorov et al. in prep). The Spitzer Science Exploration paper is ongoing (Baxter et al. in prep). The first paper for the emission spectrum of Wasp-18b is published (Arcangeli, Desert et al. 2018). My group worked with my collaborators on the understanding of the atmospheric properties of ultra-hot-Jupiters (Mansfield et al. 2018, Parmentier et al. 2018, Kreidberg et al. 2018).
(WP1:) Reduction and analysis pipeline have been completed during this period by PI, PD1, and PhD. My group is analyzing the data from a dozen of objects observed with GMOS.
(WP2:) We have compared the data to models for the first spectra extracted and estimated the planetary parameters, (Huitson, Desert et al., 2017, Desert et al. in prep, Todorov et al. in prep).
(WP3:) PhD2 has developed a comparative exoplanetology framework for the Spitzer data analyzed in this section of the proposal.

RP2: we improved the determination of the climate of close-in exoplanets through the study of the atmospheric dynamics of hot-Jupiters. The PI and PhD1 worked on the phase curve observation of WAPS-18b with HST/WFC3 (Arcangeli, Desert et al. submitted). Another draft paper is being written on this topic (Arcangeli, Desert et al. in prep).
(WP1:) PhD1 has developed a pipeline for phase-resolved spectroscopy using HST/WFC3. We have delivered NIR phase curves for the few best targets (WASP-18b, WASP-103b). HST/WFC3 data are already secured for a few objects and very promising. We will produce the first a comparative exoplanetology program based on spectroscopic phase curves.
(WP2:) My group collaborate closely with theorists who are Co-Is on the accepted proposals: Prof. Showman. Prof Line, Prof Parmentier to fit our data with their models. We invert our data to produce the maps of the brightness temperatures (NIR) and get constraints on the thermal structures.
(WP3:) PI, PhD1 and PD1 have worked on a JWST-ERS proposal for phase curve; proposal has been granted, and I expect my team to work on this data. PhD1 has produced simulations for phase curves with CHEOPS, and has presented the simulation at a CHEOPS science conference.

RP3: My team has started to work on preparing the estimate of the effect of stellar radiations and activity on exoplanet atmospheric properties and habitability by looking at the long term photometry of stellar host. Some LCOGT data has been secured, and analyzed. A pipeline for analyzing these datasets has been developed by PD1 together with a Master Student (Filipe Matos) in 2017/18. The first data from the LCO will appear in a Master Thesis project by Filipe Matos, and in Todorov et al. in prep.
Until mid-term:
RP1: My group defined new properties for ultra-hot-jupiters, a new class of exoplanets. We found that there dayside atmospheres are more similar to that of stars than planets. When the proper atmospheric physics are included, we find that the metallicity of these planets are consistent with Solar, and disprove previous findings that were at odds with well known formation scenarios for these objects (Arcangeli et al. 2018). We expect to see new trends in the atmospheric properties of these ultra hot planets in a statistical manner (Baxter et al. in prep).
PI is developing a new method to extract side spectra if exoplanets. This could lead to getting new type of information of exoplanet atmosphere.
PI may have found a new way to analyze the Multi-Object Spectroscopic data (MOS) which is something that we are currently exploring. If this new method works, it would mean that this method can be employ for any stars, and not limited to a small subset of stars as currently applied.
RP2: Similar peculiarities can be observed in the atmospheric dynamics of such planets, with perhaps magnetic field effect to slow down the winds (Arcangeli et al. submitted), and effect of changes of composition as function of the longitude (Arcangeli et al. in prep). We are currently developing a new method to spectral analyze phase curve observations, which would be important because would not rely on models to extract the longitudinal information of the planet.