Luc Dessart (Lagrange)
Thursday June 9th - 11am
IRAM Seminar Room - IRAM
In recent years, stellar explosions (or more generally supernovae, SNe), have become the focus of considerable interest in modern astrophysics. These short-lived phenomena reach extraordinary peak luminosities of 10^7 to 10^11 Lsun, making them excellent probes of the distant Universe. They represent the ultimate demise of different types of stars. The so-called SNe Ia, in part associated with the explosion of accreting white dwarfs at the Chandrasekhar mass, lead to the combustion, on a timescale of only one second, of up to a solar mass of carbon and oxygen into iron. Other SNe derive their energy not from combustion, but from the gravitational collapse
of the degenerate iron core that eventually forms at the end of the life of most massive stars. At the origin of the densest astrophysical plasmas, these core-collapse SNe are associated with neutrino and, probably, gravitational-wave emission. They produce all stellar-mass compact objects and release the oxygen we breath. SNe are the fundamental driver of the chemical evolution of the Universe since the primordial Big Bang nucleosynthesis ended.
The broad interest in SNe has driven astronomers to design better strategies to detect transient phenomena. Wide-field deep high-cadence surveys are now routinely finding SNe out to a redshift of about one, in diverse environments, as well as detecting faint and fast transients not known before.
In this talk, I will first review the properties of standard core-collapse SNe. I will then describe three types of super-luminous SNe associated with ejecta/circumstellar-medium interaction, pair-instability SNe, as well as magnetar-powered SNe. Although exotic and rare, these extraordinary events shed new perspectives on massive star mass loss and stability, the final fate of super-massive stars, as well as the physics of compact objects like magnetars.
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