Conveners
Stellar Evolution
- Inma Dominguez (Universidad de Granada)
Stellar Evolution
- Inma Dominguez (Universidad de Granada)
Stellar Evolution
- Lionel Siess (Université Livre de Bruxelles)
Stellar Evolution
- Lionel Siess (Université Livre de Bruxelles)
The initial-final mass relation of white dwarfs plays an important role across astrophysics. In a recent analysis of a few carbon-oxygen white dwarfs in intermediate-age open clusters of the Milky Way we identified a kink in the initial-final mass relation, located over a range of initial masses, 1.65 ≲ Mi/Msun ≲ 2.10, which unexpectedly interrupts the commonly assumed monotonic trend. The...
With the recent advances in infrared instruments on large telescopes, such as X-shooter and KMOS, as well as NIRSpec on JWST, near-IR spectroscopic information of different types of unresolved galaxies in various environments will increase in quantity and in quality. Stellar spectral libraries and associated stellar population models need to keep up with the times. Near-IR spectra of...
We discuss three fundamental questions in AGB star research that can be addressed by results obtained from globular clusters (GCs):
(1) Period-luminosity relations derived for the long-period variables in four GCs show a similar splitting into two sequences but also differ in the maximum luminosity reached.
(2) C/O ratios measured in O-rich AGB stars in NGC 1846 prove the increase of...
Asymptotic Giant Branch stars are of paramount importance in several fields of modern astrophysics. Their interiors are characterised by a rich nucleosynthesis, deeply connected to their surface via the recurring third dredge-up events. Nevertheless, full stellar evolution models in this phase are still plagued by uncertainties of both numeric and physics nature. The main processes that...
Binaries among post asymptotic giant branch stars (post-AGB) were historically serendipitously detected, but these turned out to have a common property: they all display a clear near-infrared excess, indicating that circumstellar dust must be close to the central star. It is now well established that this indicates the presence of a stable compact circumbinary disc. The luminous evolved...
At the end of their lives, low and intermediate mass stars scatter their envelope throughout the interstellar medium via a stellar wind. For decades, modelling endeavours of these outflows have assumed that these winds are spherically symmetric. However, recent high-spatial resolution observations reveal that the winds of evolved stars typically possess a high degree of complexity, from...
AGB stars are notoriously difficult to model with full stellar evolution codes, such as MESA, due to the various instabilities and convergence issues that arise during the thermal pulses. This makes the production of grids of AGB stars, with varying masses and metallicities, time consuming due to the large amount of human debugging required. This talk will summarise the various instabilities...
The stellar progenitors of SNe Ia are usually identified with CO WDs accreting matter in binary systems. Due to mass deposition C-burning is ignited at the center in highly degenerate physical conditions, determining the thermonuclear runaway. In this talk the interplay between weak processes and convection will be discussed and their effects on the physical and chemical properties at the...
In order to interpret the surface abundances of the most metal-poor stars detected, and infer the properties of the oldest stellar generations, it is crucial to develop models of stellar evolution and nucleosynthesis for primordial to extremely metal-poor (EMP) stars. Such models are also relevant in the context of Galactic Chemical evolution and Galactic structure formation.
We present...
Little is known about the first stars, but hints on this stellar population can be derived from the peculiar chemical composition of the most metal-poor objects in the Milky Way and in resolved stellar populations of nearby galaxies. We review the evolution and nucleosynthesis of metal-poor and extremely metal-poor (EMP) stars with low and intermediate masses. In particular, new models of 6...
The high temperature and density that develop within the cores of evolved stars, from red giants to supergiants, make them ideal sites to investigate deviations from the standard models describing the behaviour of matter in extreme conditions. Note that these conditions are often not accessible by current laboratory experiments. A growing amount of scientific papers discuss various methods to...
The explosion mechanism of core-collapse supernovae has been a longstanding problem in nuclear astrophysics. In the last decade, important steps towards a thorough understanding of what causes supernovae to explode have been made, thanks to the development of very detailed three-dimensional simulations. However, a lot of work still needs to be done. In this talk, I will focus on the connection...
We study the effects of a beyond-Horndeski theory of modified gravity in the interior of a population II star. We consider a simple phenomenological model of a 1.1M star that has left the main sequence, has a thin Hydrogen burning shell with a partially degenerate isothermal core, surrounded by a radiative envelope having two regions of distinct opacities. Using suitable matching conditions at...
