Pre-Supernova Neutrinos


Astronomy research
  Software Infrastructure:
     My instruments
  White dwarf supernova:
     Stable nickel production
     Remnant metallicities
     Colliding white dwarfs
     Merging white dwarfs
     Ignition conditions
     Metallicity effects
     Central density effects
     Detonation density effects
     Tracer particle burning
     Subsonic burning fronts
     Supersonic burning fronts
     W7 profiles
  Massive star supernova:
     Rotating progenitors
     3D evolution
     26Al & 60Fe
     44Ti, 60Co & 56Ni
     Yields of radionuclides
     Effects of 12C +12C
     SN 1987A light curve
     Constraints on Ni/Fe ratios
     An r-process
  Neutron Stars and Black Holes:
     Black Hole mass spectrum
     Compact object IMF
     He burn on neutron stars
     Variable white dwarfs
     Pop III with JWST
     Neutrino HR diagram
     Monte Carlo massive stars
     Pre-supernova neutrinos
     Pre-supernova variations
     Monte Carlo white dwarfs
     SAGB stars
     Nugrid Yields I
     Classical novae
     He shell convection
     Presolar grains
     BBFH at 40 years
  Chemical Evolution:
     Iron Pseudocarbynes
     Radionuclides in the 2020s
     Hypatia catalog
     Zone models H to Zn
     Mixing ejecta
     γ-rays within 100 Mpc
  Thermodynamics & Networks
     Stellar EOS
     12C(α,γ)16O Rate
     Proton-rich NSE
     Reaction networks
     Bayesian reaction rates
  Verification Problems:
     Validating an astro code
Software instruments
cococubed YouTube
Bicycle adventures
Public Outreach
Education materials
2022 ASU Solar Systems Astronomy
2022 ASU Energy in Everyday Life

AAS Journals
AAS YouTube
2022 Earendel, A Highly Magnified Star
2022 TV Columbae, Micronova
2022 White Dwarfs and 12C(α,γ)16O
2022 MESA VI
2022 MESA in Don't Look Up
2022 MESA Marketplace
2012-2023 MESA Schools
2022 MESA Classroom
2021 Bill Paxton, Tinsley Prize

Contact: F.X.Timmes
my one page vitae,
full vitae,
research statement, and
teaching statement.
Presupernova neutrinos: directional sensitivity and prospects for progenitor identification (2020)

In this article we explore the potential of current and future liquid scintillator neutrino detectors of $\mathcal O (10)$ kt mass to localize a pre-supernova neutrino signal in the sky. In the hours preceding the core collapse of a nearby star (at distance $D \lesssim$ 1 kpc), tens to hundreds of inverse beta decay events will be recorded, and their reconstructed topology in the detector can be used to estimate the direction to the star. Although the directionality of inverse beta decay is weak ($\sim$8% forward-backward asymmetry for currently available liquid scintillators), we find that for a fiducial signal of 200 events (which is realistic for Betelgeuse), a positional error of $\sim$60$^\circ$ can be achieved, resulting in the possibility to narrow the list of potential stellar candidates to less than ten, typically. For a configuration with improved forward-backward asymmetry ($\sim$40%, as expected for a lithium-loaded liquid scintillator), the angular sensitivity improves to $\sim$15$^\circ$, and -- when a distance upper limit is obtained from the overall event rate -- it is in principle possible to uniquely identify the progenitor star. Any localization information accompanying an early supernova alert will be useful to multi-messenger observations and to particle physics tests using collapsing stars.


Number of events at a 17 kt liquid scintillator detector

Cumulative number at a 17 kt liquid scintillator detector

Nearby core collapse supernova candidates

Mollweide projection of nearby core collapse supernova candidates.

Geometry of inverse beta decay in liquid scintillator

Angular uncertainty of localization

Antares 4 hours before collapse

Antares 1 hour before collapse

Antares 2 min before collapse

Neutrinos from beta processes in a presupernova: probing the isotopic evolution of a massive star (2017)

In this article we present a new calculation of the neutrino flux received at Earth from a massive star in the $\sim$ 24 hours of evolution prior to its explosion as a supernova (presupernova). Using the stellar evolution code MESA, the neutrino emissivity in each flavor is calculated at many radial zones and time steps. In addition to thermal processes, neutrino production via beta processes is modeled in detail, using a network of 204 isotopes. We find that the total produced $\nu_e$ flux has a high energy spectrum tail, at E $\gtrsim$ 3 - 4 MeV, which is mostly due to decay and electron capture on isotopes with A = 50 - 60. In a tentative window of observability of E $\gtrsim$ 0.5 MeV and t < 2 hours pre-collapse, the contribution of beta processes to the $\nu_e$ flux is at the level of $\sim$ 90% . For a star at D=1 kpc distance, a 17 kt liquid scintillator detector would typically observe several tens of events from a presupernova, of which up to $\sim$ 30% due to beta processes. These processes dominate the signal at a liquid argon detector, thus greatly enhancing its sensitivity to a presupernova.

neutrino luminosity evolutions
neutrino spectra
$\nu$ luminosity evolution at different energies

fluxes at earth for 15 M$_{\odot}$
fluxes at earth for 30 M$_{\odot}$