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General description

The TEMPO project (Temporal Evolution and Metamorphosis of exoPlanets and their atmOspheres, PI: Jorge Lillo-Box) aims at tackling the study of the evolution of exoplanets and their atmospheres focused on two aspects, 1) their evolution over time as the star ages and 2) the imprints on the atmospheric properties caused by the architectural evolution of planetary systems (e.g., migration).

After the detection of the first transiting exoplanets, the characterization of their atmospheres rapidly became one of the most relevant focuses in the field. This external planetary envelope contains key information about the formation and evolution processes and hides the interior of the planet as seen from us. In an astrobiological context, as well, the atmosphere is the most obvious layer where we could detect the imprints of the existence of life on a planet, through the remote detection of the so-called biomarkers. This field has largely grown in the past decade and we are now in the time for JWST and high-resolution spectrographs attached to large telescopes to move on to the next steps. The techniques are settled and the instrumentation is ready to explore the different chemical components. Within this decade, the field will get the highest precision atmospheric spectra from gaseous and potentially rocky planets. The challenge for this decade is how to use these techniques and information at hand to farther study the exoplanet diversity and to understand what chemical species (or combinations of them) can define a planet as inhabited.

On the other hand, the large population of planets around main-sequence stars is already providing key insights about the planet formation process and how planetary systems are built to finally reach their present architecture. By contrast, very little is known about the evolution of these systems once the star ages towards the red giant branch. Indeed, the life and properties of a planet are closely linked to the life and properties of its host star. The detection of extrasolar planets beyond the main sequence thus represents an opportunity to study the coupling between stellar and planetary evolution. However, among the more than 5000 planets discovered around other stars, only 200 have been detected around evolved stars ascending the red giant branch (RGB). And this relatively small population is dominated by long-period planets orbiting beyond 0.5 AU, with a paucity of planets in the close-in regions, pointing to the engulfment of close-in planets once the star evolves off the main sequence. However, a small population of ~20 daring exoplanets stands up to their giant parents and has been able to elude their fate. This population started with the detection of Kepler-91b (Lillo-Box et al., 2014a, 2014b). The challenge for this decade is to study the evolution of planetary systems as their host star ages to understand our own future and to learn about planet occurrence in more massive stars. Likewise, stellar age is a key factor both for understanding the different processes of the formation of planetary systems and for understanding abiogenesis and the possible evolutionary stage of life that may have arisen on the planets.

TEMPO will exploit (over the two years comprising the awarded project) ground and space-based observations for exoplanet atmospheric characterisation in different niches. Some of these proposals have already been awarded to the PI of this proposal in state-of-the-art instrumentation like ESPRESSO and HARPS-NIRPS (ESO) and will be executed along 2024. These observations will become a first in the exoplanet field (see description below) and will provide key insights into how exoplanets evolve in time.

TEMPO is a project funded by the Spanish Ministry of Science, Innovation and Universities (MICIU/AEI /10.13039/501100011033) and the European Union NextGenerationEU/PRTR under code CNS2023-144309.

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