Pre-Supernova Neutrinos


Astronomy research
  Software Infrastructure:
     My instruments
  White dwarf pulsations:
     12C(α,γ) & overshooting
     Probe of 12C(α,γ)16O
     Impact of 22Ne
     Impact of ν cooling
     Variable white dwarfs
     MC reaction rates
  White dwarf supernova:
     Stable nickel production
     Remnant metallicities
     Colliding white dwarfs
     Merging white dwarfs
     Ignition conditions
     Metallicity effects
     Central density effects
     Detonation density
     Tracer particle burning
     Subsonic burning fronts
     Supersonic fronts
     W7 profiles
  Massive stars:
     Pop III with HST/JWST
     Rotating progenitors
     3D evolution to collapse
     MC reaction rates
     Pre-SN variations
  Massive star supernova:
     Yields of radionuclides
     26Al & 60Fe
     44Ti, 60Co & 56Ni
     SN 1987A light curve
     Constraints on Ni/Fe
     An r-process
     Effects of 12C +12C
  Neutron Stars and Black Holes:
     Black Hole spectrum
     Mass Gap with LVK
     Compact object IMF
     He burn neutron stars
  Neutrino Emission:
     Neutrino emission from stars
     Identifying the Pre-SN
     Neutrino HR diagram
     Pre-SN Beta Processes
     Pre-SN neutrinos
     Hypatia catalog
     SAGB stars
     Nugrid Yields I
     He shell convection
     BBFH at 40 years
     γ-rays within 100 Mpc
     Iron Pseudocarbynes
  Pre-Solar Grains:
     C-rich presolar grains
     SiC Type U/C grains
     Grains from massive stars
     Placing the Sun
     SiC Presolar grains
  Chemical Evolution:
     Radionuclides in 2020s
     Zone models H to Zn
     Mixing ejecta
  Thermodynamics, Opacities & Networks
     Radiative Opacity
     Skye EOS
     Helm EOS
     Five EOSs
     Equations of State
     12C(α,γ)16O Rate
     Proton-rich NSE
     Reaction networks
     Bayesian reaction rates
  Verification Problems:
     Validating an astro code
Software Instruments
AAS Journals
   2024 AAS YouTube
   2024 AAS Peer Review Workshops

2024 ASU Energy in Everyday Life
2024 MESA Classroom
Outreach and Education Materials

Other Stuff:
   Bicycle Adventures

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$_{\odot}$