Short-Lived Radioisotope ^{98}Tc Synthesized by the Supernova Neutrino Process

Area of Science:

• Nuclear astrophysics
• Cosmochemistry
• Supernova physics

Background:

• The radioactive isotope Technetium-98 (Tc-98) has a long half-life and could have existed in the early Solar System.
• Understanding the origin of presolar nucleosynthesis products is crucial for Solar System formation models.

Purpose of the Study:

• To calculate the production of Tc-98 via neutrino-induced reactions (the "nu process") in core-collapse supernovae.
• To assess the potential abundance of Tc-98 at the time of Solar System formation.
• To explore the use of Tc-98 as a nuclear cosmochronometer.

Main Methods:

• Performed the first calculations of Tc-98 production through neutrino-nucleus reactions in supernovae.
• Modeled the "nu process" nucleosynthesis, including charged current reactions with electron antineutrinos.

Main Results:

• Predicted Tc-98 abundance is close to the measured upper limit, suggesting potential for future detection.
• Calculated a significant contribution (~20%) from charged current reactions with electron antineutrinos to Tc-98 nucleosynthesis.
• Demonstrated that precise Tc-98 abundance measurements could refine the timescale between supernovae and Solar System formation.

Conclusions:

• Tc-98 production via the "nu process" in supernovae is feasible and may explain its early Solar System presence.
• Tc-98 serves as a novel probe for electron antineutrino properties, particularly temperature.
• The Tc-98 nuclear cosmochronometer offers a new tool for precise dating of astrophysical events preceding Solar System formation.