Speaker
Jordi Jose
(Institut d'Estudis Espacials de Catalunya/UPC)
Description
Classical nova outbursts are powered by thermonuclear runaways (hereafter,
TNRs) that take place in the hydrogen-rich accreted envelopes of white dwarfs in
close binary systems. Extensive numerical simulations of nova outbursts have shown
that the accreted envelopes attain peak temperatures ranging between 100 and 400 MK
for about several hundred seconds, and therefore, their ejecta is expected to show
signatures of a significant nuclear activity, Indeed, it has been claimed that novae
can play a certain role in the enrichment of the interstellar medium through a
number of intermediate-mass elements. This includes 17O, 15N and 13C, systematically
overproduced in huge amounts with respect to solar abundances, with a lower
contribution in a number of other species with A < 40, such as 7Li, 19F, or 26Al.
Estimates of the contribution of novae to the Galactic abundances usually
rely on poorly known quantities, and implicitly assume that novae have been the same
sort of objects during the whole Galaxy's history: that is, an explosion on a
particular white dwarf, of a given mass and luminosity, is today similar to those
contaminating the interstellar medium in the early epochs of the Galaxy. In this
presentation, we analyse the first nova explosions and demonstrate that these
objects were more important contributors to the Galactic abundances in the past.
Author
Jordi Jose
(Institut d'Estudis Espacials de Catalunya/UPC)
Co-authors
Prof.
Enrique García-Berro
(Institut d'Estudis Espacials de Catalunya/UPC)
Dr
Margarita Hernanz
(Institut d'Estudis Espacials de Catalunya/CSIC)
Dr
Pilar Gil-Pons
(Univ. Politecnica de Catalunya)
