Supernovae, neutrinos and the chirality of amino acids

Abstract

A mechanism for creating an enantioenrichment in the amino acids, the building blocks of the proteins, that involves global selection of one handedness by interactions between the amino acids and neutrinos from core-collapse supernovae is defined. The chiral selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the (14)N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. It also requires an asymmetric distribution of neutrinos emitted from the supernova. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earth's proteinaceous amino acids.

Keywords: amino acids; chirality; molecular clouds; origin of life; supernova neutrinos.

Figure 1

Schematic diagram of the magnetic fields, B, surrounding a nascent neutron star and the spins of the ¹⁴N nuclei, SN, and of the neutrinos, S_ν, emitted from the supernova that created the neutron star.

Figure 2

Magnetic substate distributions for ¹⁴N nuclei resulting from the Buckingham effect. The “x” indicates the states that will undergo greater processing from the electron antineutrinos. NL refers to left-handed ¹⁴N nuclei, and NR to right-handed ¹⁴N nuclei. “Outgoing (Incoming) throat” refers to the throat of the neutron star at which the magnetic field is outgoing (incoming). The thickness of the line for each substate indicates its relative population.