AstroSem -- summer semester 2018

For the AstroSem of the Master of Astrophysics programme in the Summer Semester 2018 I propose the following paper:
"Binary stars in the Galactic thick disc" by Rob Izzard and collaborators.
The authors of this paper studied the properties of a family of peculiar red giant stars that are observed in the Thick Disk of the Milky Way. Thank to the asteroseismological data collected by the Kepler satellite, it was possible to determine the masses and ages of these stars, which is approximately 5 billion years or older. Surprisingly, a significant fraction of these stars have a mass exceeding approximately 1.3 solar masses, which means that they are more massive than they should be given their age and metallicity. In addition, these stars have rather peculiar abundance ratios. In particular, the ratio of carbon to nitrogen cannot be reproduced by standard models of single-star evolution. The authors explore the possibility that these peculiar red giant stars might have formed in binary or multiple systems, and that the anomalous masses and surface abundances might be explained by episodes of mass transfer or stellar mergers occurred in the past.

Contact me if you are interested!
In general I'm available to meet and discuss every day between 9.30(ish) and 18.30(ish), unless I'm travelling or there is a meeting or a seminar.

Previous projects.

AstroSem -- summer semester 2017

For the AstroSem of the Master of Astrophysics programme in the Summer Semester 2017 I proposed the following paper: "Merging binary black holes formed through chemically homogeneous evolution in short-period stellar binaries" by Ilya Mandel and Selma de Mink.
The paper suggests a new formation scenario to create binary black holes which merge within a Hubble time producing gravitational waves possibly detectable by the instruments of the Virgo and LIGO collaborations. Vsevolod Nedora very passionately presented it on May 15th.