Amino Acid Chiral Selection Via Weak Interactions in Stellar Environments: Implications for the Origin of Life

Abstract

Magnetochiral phenomena may be responsible for the selection of chiral states of biomolecules in meteoric environments. For example, the Supernova Amino Acid Processing (SNAAP) Model was proposed previously as a possible mode of magnetochiral selection of amino acids by way of the weak interaction in strong magnetic fields. In earlier work, this model was shown to produce an enantiomeric excess (ee) as high as 0.014% for alanine. In this paper we present the results of molecular quantum chemistry calculations from which ees are determined for the α-amino acids plus isovaline and norvaline, which were found to have positive ees in meteorites. Calculations are performed for both isolated and aqueous states. In some cases, the aqueous state was found to produce larger ees reaching values as high as a few percent under plausible conditions.

Figure 1

The isovaline cation ee as a function of time for a meteoroid penetrating the external magnetic field for scenarios described in the text, (a) B = 800 T with high f, (b) B = 800 T with low f, (c) B = 30 T with high f, and (c) B = 30 T with low f. Values of f are indicated beside the lines. In all cases v = 0.015c. For plots (b) and (d) the values of f should be multiplied by 10⁻⁸.

Figure 2

The ee produced in zwitterionic alanine orbiting a neutron star for various average radii and times.