Szczegóły seminarium
Data: 10.01.2023
Jakub Klencki (ESO, Garching)
Massive stars in nearby dwarf galaxies: key to the origin of black hole mergers
Streszczenie:
The last few years have seen an unprecedented growth in all the aspects
of gravitational-wave (GW) astrophysics. At the frontier is population
modeling of GW sources and their potential progenitors: massive stars in
binary systems. Various clues suggest that bulk of the population of
binary black hole mergers may have formed in metal-poor environments.
This is likely because low-metallicity stars experience reduced mass
loss through winds, allowing them to form more massive black holes. The
pressing question is thus now: how well do we really understand the
''basics'' of stellar evolution and the ''classical'' formation
scenarios in the regime of low metallicity? In my talk, I will argue
against the formation of massive binary black holes through the
common-envelope evolution, one of the most prominent channels discussed
in the literature. Furthermore, I will show that the textbook picture of
mass transfer evolution, where a giant star is stripped of its envelope
by an accreting companion, may no longer hold in the case of massive
stars at low metallicity. I will discuss implications of our findings
for various classes of objects (stripped stars, supernova projenitors,
X-ray binaries, LIGO/Virgo sources) and highlight the crucial role of
observational constraints coming from young stellar populations in
nearby metal-poor dwarf galaxies, now and in the future.