Presupernovae as powerful neutrino sources detectable by next neutrino experiments M. Kutschera, A....

Presupernovae as powerful neutrino sources

detectable by next neutrino experiments

M. Kutschera, A. Odrzywołek, M. Misiaszek

Ustroń 2009

• Neutrino astrophysics group

• Institute of Physics, Jagellonian University, Kraków, Poland:

A.Odrzywołek, M. Misiaszek, M.K.

References to our papers: arXiv

Neutrino spectra available at

• Research summary:

• Spectra of neutrinos from stars at late stages of thermonuclear burning (presupernovae) are found

• This allows us to predict counting rates in various neutrino detectors

• Presupernovae seem to be detectable by next generation of neutrino detectors

• Stars with initial mass (ZAMS) M>9Msol

after red giant phase:– ignite carbon– develope iron core – end life as core-collapse supernovae

– example: 15 Msol :

Nearby candidate:

- Betelgeuse in ORION constellation

- distance 130 pc

• After carbon ignition neutrino-cooled stars

• Photon luminosity much less

L<<Lν

than neutrino luminosity.-photon luminosity constant after carbon ignition

-neutrino luminosity grows by many orders!

Strong temperature growth in the core

Can neutrino experiments detect presupernovae?

• Pair annihilation dominant• Antineutrino flux from pair annihilation crucial !• Different than for the Sun (only neutrinos)

High density – neutrino and antineutrino spectra differ

• Near the collapse:– Total flux grows as Lν ~Tc

9

– Mean neutrino energy grows

Predictions for various detectors

• Range one day before collapse (various detectors)

Presupernova neutrinos vs geoneutrinos

• Nuclear reactions produce more neutrinos νe

than pair annihilation

• More than 1000 nuclei must be included

Weak nuclear reactions: neutrinos excess

Comparison with solar neutrinos

REAL NEUTRINO ASTRONOMY

STARTS