In early March 2022, Felipe Lagos defended his thesis to obtain the degree of PhD in Astrophysics from the University of Valparaiso. His research, entitled “White dwarfs in binaries and hierarchical triple systems as a test for mass transfer models and close binary formation mechanisms”, obtained the highest grade. Lagos, who is also a member of the Nucleus Millennium of Planetary Formation (NPF), focused his doctoral work on the formation of white dwarfs in binary and triple stellar systems and was supervised by Matthias Schreiber, Director of the NPF.

This defense was conducted in person, after more than two years in which the University of Valparaiso, due to the sanitary condition of the country, conducted them online.

The research was developed in three different contexts: type Ia supernova progenitor systems, formation of low-mass white dwarfs, and the survival of planets after the host star transformed into a white dwarf.

“In the first investigation, we found evidence that binaries with white dwarfs, formed through stable, non-conservative mass transfer, could play an important role in the formation of type Ia supernovae, and their inclusion in future simulations could be instrumental in modeling the occurrence of these explosions. In the second investigation, we used triple stellar systems to test and corroborate predictions of theoretical models of binary star evolution, while in the last investigation we demonstrated that a recently discovered planet candidate, which orbits a white dwarf at only 0.02 astronomical units, could have acquired that (very small) orbit through what we call common envelope evolution,” explains Lagos.

Regarding Lagos’ future work, in May of this year he will join the astronomy group at the University of Warwick, England, to work together with astrophysicist Boris Gansicke. While his research will continue to focus on white dwarfs, the emphasis will be on analyzing their spectra. “The ultimate goal is to be able to characterize and generate a database to study the abundance of heavy elements that could come from exoplanets, asteroids, comets, etc. being accreted by white dwarfs,” says the astronomer, who will also continue working on five other projects related to white dwarfs and evolved stars, led by his PhD mentors.