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