MSV-2035 Astronomy Document - Inside Design - FINAL - FINAL

Astronomy & Astrophysics 22 For instance, the dependence on stellar age, effect of detailed abundances, metallicity threshold for efficiency of formation, are important areas that are less explored. The mass functions, orbital eccentricity, and metallicity of giant planets strongly suggest multiple formation channels which need confirmation with the growing database. The need of the hour is to resolve intrinsic biases and sensitivities of different techniques that have made it very challenging to combine demographics over a large parameter space. The driving force behind exoplanetary research is the search for habitable planets beyond the solar system. From the scientific perspective, conditions of habitability depend on intrinsic planetary characteristics, the external space environment governed by the stellar host, their interactions and coupled evolution. Short term fluctuations in stellar activity due to flares and mass ejections produce intense high energy radiation and energetic particles which perturb planetary atmospheres. Slower, long-term evolution of stellar winds influence planetary atmospheres and play a role in their evolution, phenomena which are governed by the presence, or lack of planetary magnetospheres. It has come to be recognized in recent times that these aspects of star-planet interactions play a critical role, along with intrinsic evolution, in determining exoplanetary habitability. Therefore, characterizing host star activity levels, searching for detectable signatures of star planet interactions and presence or absence of magnetospheres in exoworlds, either through stellar monitoring programmes, transit spectroscopy of exoplanets, auroral radio emission or other means has become an area of immense topical interest. Recent observations have shown beyond doubt that the grain growths in protoplanetary discs starts early, and they even have significant structures in the dust distributions observable with sub-mm interferometry. Are these structures indicators of successful fast planet formation? While we have a good understanding of forming centimeter sized pebbles from grains, the method of growing the larger sized planetesimals out of pebbles is still not fully understood. What are the mechanisms by which planetesimals are grown into full scale planets and can they explain the exoplanet demographics currently observed around our nearby stars, are still all open questions. The thermal and chemical environments in protoplanetary discs and how they evolve over time to influence the planet formation is also something that is not fully understood. This is important to explain the volatile and non-volatile elemental abundance gradients we see in our own solar systemas well as in other exoplanets. The field of exoplanetary science has also entered the era of detailed atmospheric characterization. The spectra of planetary atmospheres reveal not only their physical and chemical properties, but also unravels crucial information about the various atmospheric processes. One of the most fundamental scientific advancements in the next decade is the detailed comparative exoplanetology of hundreds of exoplanets using transit spectroscopy, direct imaging, and high-resolution Doppler spectroscopy. Elemental abundances of exoplanetary atmospheres is essential to understand the formation, evolution and migration scenarios. The origin of hot-Jupiters, that have been in the limelight since the last 25 years, is hypothesized to be either in situ formation or migration to the current location. Migration can occur either through interaction with the protoplanetary disk during their formation or by 'disk-free' mechanisms such as gravitational interactions with a third body. The observed spin-orbit misalignment in such systems may hint at a disk- free migration but migration can also happen through misaligned disks. Recent theoretical studies suggest that chemical abundances could provide new constraints on the mode of migration thus highlighting the need for detailed atmospheric characterization. Exoplanet detection surveys have revealed the high occurrence rate of rocky exoplanets in the solar neighbourhood with a dozen in their habitable zones. The goal is to detect biosignatures in this population with the low-mass stellar hosts being the best suited. Defining a robust biosignature is theoretically challenging but MEGA SCIENCE VISION-2035