The Fondecyt 2021 competition, of the Agencia Nacional de Investigación y Desarrollo (ANID), granted funding for 3 projects of researchers of the Núcleo Milenio de Formación Planetaria (NPF), one regular and two for postdoctoral research, which will be developed for the next 4 and 3 years, respectively. They are the associate researcher Jorge Cuadra, and the postdoctoral researchers Mario Sucerquia and Odette Toloza.
The Fondecyt research project of Jorge Cuadra focuses on the Galactic Center, a line of research that works in parallel to the NPF topics. In particular, it deals with the study of the interaction between stars, gas, and the central black hole of the Milky Way.
At the galactic center is Sgr A*, the supermassive black hole of our galaxy. Around it are about 30 very massive stars, which lose a lot of mass through stellar winds. When these winds collide with each other the gas gets very hot, but some of it can also form cold clumps. “With this project we want to use simulations to better understand how this cold gas is produced, which, although it is a small fraction, is important because it is more easily captured by the black hole. This cold gas can as well as be observed with ALMA, and we will be able to compare our simulations with the observations,” explains Jorge Cuadra, who is also an academic at the Universidad Adolfo Ibañez and leader of the Max Planck Partner Group on Galactic Centre Astrophysics.
Another interesting topic that is part of the project, adds the astrophysicist, is the development of virtual reality visualizations. One of them can be seen at the following link: https://jrcuadra.github.io/plaga/divulgacion/
Mario Sucerquia has named his research topic “The lost rings”. The thousands of exoplanets discovered to date have given us great lessons on how planetary systems are born, evolve and die, explains the researcher. “These decades of exploration beyond the far reaches of the Solar System have taught us that there are many surprising features and phenomena associated with planets never before seen among our planetary neighbors in the solar system. Evaporating planets, collisions between them, giant exo-comets, among others, are part of this collection of these recently discovered planetary systems. The curious thing is that one of the most notorious features of the Solar System for its beauty, the planetary rings, are still hidden from our telescopes, even though the conditions seem to be ripe for their discovery”, he indicates.
Where are these “lost rings” is the question that his project seeks to answer, through the modeling of how they should form and evolve, and what morphological and physical characteristics they should have, to know precisely what is the footprint of these objects in the immense photometric monitoring of the instruments designed to search for exoplanets. In this way, a systematic search for these systems can be carried out until they are discovered and characterized.
On the other hand, adds Sucerquia, these rings are the gateway to know the planetary magnetic fields, and with them, the functioning and composition of its interior, and finally, the evolutionary relationship between the planet and its possible moons.
Odette Toloza’s research project seeks to study white dwarfs contaminated by metals from planetary debris. White dwarfs are the final stage of some stars, such as the Sun. “During this evolution process, part of the solar system will survive. Then some instabilities in the system will make the orbits of planets and asteroids more eccentric. Eventually, these bodies come very close to the white dwarf and its strong gravity will tear them apart. This shattered material will form a thin disk around and begin to be deposited on the white dwarf and contaminate its atmosphere. This corresponds to the prediction for our solar system. And to be more precise, we study other exo-systems that have already gone through this process”, explains Toloza.
An important ingredient for this research is the shape of the white dwarf. These stars are incredibly compact and, therefore, the gravity is 100 million times stronger than that of the Earth, so they can disintegrate objects that pass close to it. As a consequence, the chemical elements are stratified in the star by layers (in analogy to the layers of an onion). That is, the heavier ones (e.g. carbon, oxygen, iron) sink towards the center of the white dwarf and the lighter ones float on the surface (hydrogen or helium). “We therefore expect the atmosphere of white dwarfs to be composed of hydrogen and/or helium. Based on this stratification, we can perform the analysis of the chemical composition of any material other than hydrogen and/or helium that is deposited on it, where we can finally infer the nature of the objects that have formed the disk”, clarifies the scientist.