Periodic Reporting for period 2 - SPICE DUNE (A SpectroPhotometric Inquiry of Close-in Exoplanets around the Desert to Understand their Nature and Evolution)
Période du rapport: 2022-09-01 au 2024-02-29
The goal of SPICE DUNE is to determine the origin of the hot Neptune desert, a deficit of Neptune-size planets on very short orbits. This mysterious feature contains the imprint of processes that shaped the population of exoplanets orbiting close to their star - and further. The relative role and the coupling of these processes, in particular atmospheric evaporation and orbital migration on secular timescales, remain unclear. This is because we lack optimal observational tracers to validate and constrain numerical models of exoplanet evolution. SPICE DUNE thus aims at gathering observations of escaping atmospheres from gas giants to super-hot rocky planets all around the desert. These data will drive the development of self-consistent models of upper atmosphere then used to derive the planets' erosion rate. We will combine for the first time these erosion rates with measurement of the planets' orbital architecture to constrain population syntheses coupling long-term orbital and atmospheric evolution of close-in planets. This ambitious approach, exploiting advanced modelling informed by the most relevant tracers, will unveil the evolutionary tracks of exoplanets and bring insights into their nature.
The proposed research addresses high-priority questions related to the origins of close-in planets, and has implications for the origin of both extrasolar systems and our own solar system's evolution.
The proposed research addresses high-priority questions related to the origins of close-in planets, and has implications for the origin of both extrasolar systems and our own solar system's evolution.
SPICE DUNE articulates into three work packages (WPs): AGATE (Analyzing Giants Atmospheric Escape), JADE (Joining Atmosphere and Dynamics for Exoplanets), and JASPER (Judging the Amplitude of Small Planets ERosion). As of February 2024 the team has published 60 articles in international refereed journals, receiving more than 600 citations (source: NASA ADS). Out of these 60 articles, eight are led by SPICE DUNE team members (two are led by one of the project PhD student). Green open access has been enforced for all publications through the arXiv server, and results have been disseminated through conferences, press releases, interviews and illustrations. The team obtained several open time observing programs on space-borne and ground-based instruments (including four programs led by one of the team PhD student, and the largest transit program ever granted on the VLT) and participates in guaranteed observation programs on cutting-edge instrumentation (CHEOPS, ESPRESSO, NIRPS).
Main work and results :
- Pathfinder series of publications to study atmospheric escape and orbital architecture in a sample of planets around the Neptunian desert (DREAM I, Bourrier et al. 2023, 669, A63 - JADE; DREAM II, Attia et al. 2023, 674, A120 - JADE, DREAM III, Guilluy et al. 2023, 676, A130 – AGATE; PR: https://www.unige.ch/medias/en/2023/migration-tumultueuse-en-bordure-du-desert-des-neptunes-chaudes(s’ouvre dans une nouvelle fenêtre)).
- Design of a new technique (the Rossiter-McLaughlin “Revolutions”) to measure the orbital architecture of exoplanets, used to discover a system with two planets on perpendicular orbits (Bourrier et al. 2021, A&A 654, A152; JADE; PR: https://www.unige.ch/medias/en/2021/les-orbites-renversantes-dun-systeme-multi-planetaire(s’ouvre dans une nouvelle fenêtre))
- Development of the numerical code JADE to simulate the coupled atmospheric and dynamical evolution of a close-in planet system over secular timescales (Attia et al. 2021, A&A, 647, A40 - JADE)
- Upgrade of the 3D numerical code EVE to simulate the escaping atmosphere of hot giant planets (Dethier & Bourrier 2023, A&A 674, A86 - AGATE).
- Development of NIGHT, novel concept of spectrograph to survey helium escaping from exoplanets (Farret Jentink et al., MNRAS, 527, 3 - AGATE)
Main work and results :
- Pathfinder series of publications to study atmospheric escape and orbital architecture in a sample of planets around the Neptunian desert (DREAM I, Bourrier et al. 2023, 669, A63 - JADE; DREAM II, Attia et al. 2023, 674, A120 - JADE, DREAM III, Guilluy et al. 2023, 676, A130 – AGATE; PR: https://www.unige.ch/medias/en/2023/migration-tumultueuse-en-bordure-du-desert-des-neptunes-chaudes(s’ouvre dans une nouvelle fenêtre)).
- Design of a new technique (the Rossiter-McLaughlin “Revolutions”) to measure the orbital architecture of exoplanets, used to discover a system with two planets on perpendicular orbits (Bourrier et al. 2021, A&A 654, A152; JADE; PR: https://www.unige.ch/medias/en/2021/les-orbites-renversantes-dun-systeme-multi-planetaire(s’ouvre dans une nouvelle fenêtre))
- Development of the numerical code JADE to simulate the coupled atmospheric and dynamical evolution of a close-in planet system over secular timescales (Attia et al. 2021, A&A, 647, A40 - JADE)
- Upgrade of the 3D numerical code EVE to simulate the escaping atmosphere of hot giant planets (Dethier & Bourrier 2023, A&A 674, A86 - AGATE).
- Development of NIGHT, novel concept of spectrograph to survey helium escaping from exoplanets (Farret Jentink et al., MNRAS, 527, 3 - AGATE)
The new technique that we developed to measure orbital architectures gives access to planets that could not be studied previously, down to Earth-size and transiting faint, slow-rotating stars. This will allow extending orbital architectures measurements to a broader sample of close-in planets.
On the atmospheric side we upgraded beyond the state of the art our 3D code of evaporating exoplanets, EVE, to interpret transit spectroscopy datasets while accounting for contamination by the star. Next is the inclusion of an advanced model to describe extended upper atmospheres and interpret helium signatures. The final version of EVE will allow constraining mass losses to a high precision in a large sample of close-in planets. These constraints will be brought in part by NIGHT, a novel concept of near-infrared spectrograph (narrow-band, high-resolution, compact, and portable) that we are developing to monitor escaping helium.
Mass loss and orbital architecture measurements are used as constraints in JADE, an original model that we developed to couple the atmospheric and dynamical secular evolution of close-in exoplanets. We showed the critical feedback of the atmosphere on dynamical migration, suggesting a specific evolution for planets at the border of the Neptunian desert. We will use JADE to implement these evolutionary pathways in population synthesis and determine the origins of the various classes of close-in planets.
On the atmospheric side we upgraded beyond the state of the art our 3D code of evaporating exoplanets, EVE, to interpret transit spectroscopy datasets while accounting for contamination by the star. Next is the inclusion of an advanced model to describe extended upper atmospheres and interpret helium signatures. The final version of EVE will allow constraining mass losses to a high precision in a large sample of close-in planets. These constraints will be brought in part by NIGHT, a novel concept of near-infrared spectrograph (narrow-band, high-resolution, compact, and portable) that we are developing to monitor escaping helium.
Mass loss and orbital architecture measurements are used as constraints in JADE, an original model that we developed to couple the atmospheric and dynamical secular evolution of close-in exoplanets. We showed the critical feedback of the atmosphere on dynamical migration, suggesting a specific evolution for planets at the border of the Neptunian desert. We will use JADE to implement these evolutionary pathways in population synthesis and determine the origins of the various classes of close-in planets.