Speaker
Description
Are there other planets like the Earth in the universe? 30 years ago, this question seemed only another example of some of the oldest, unsolvable questions of humanity. However, today, we are privileged to, for the first time in history, state that there are other planets orbiting distant stars.
Exoplanets are planets outside the solar system. So far, more than 5600 of them have been discovered – in fact, this number has experienced an exponential growth during the last decades. One of the main peculiarities of extrasolar planets is the huge diversity of worlds that exist, ranging from lava planets to super-Earths or hot Jupiters. Actually, planets of the solar system fall into a poor exoplanet population region regarding their period-radius relation.
For instance, most extrasolar worlds have sizes bigger than the Earth and smaller than Neptune, this is, without anything similar in our own system. These planets lead to degeneracies and contradiction regarding their compositions – they may even be ocean worlds! Therefore, they are key to understanding planetary formation and evolution.
Exoplanets are usually first spotted by space telescopes, such as Kepler/K2 and TESS, when they transit, this is, pass between the observer and their host star, producing changes on its flux. Secondly, follow up observations are made using ground-based telescopes to validate transits and obtain parameters such as the radius or the orbital period of the planet.
Next, thanks to methods such as radial velocity, based on gravitational interactions between a star and an exoplanet, the mass of the latter can be precisely measured, leading to estimations of its planetary density. Finally, the latest technological developments, such as JWST, allow to study exoplanetary atmospheres, detecting hazes, winds and even molecules such as biomarkers, this is, gases that may potentially be a consequence of the presence of life.
