Abiogenesis on Different Star Types; a Dissipative Photochemical Perspective

Abstract

From the non-equilibrium thermodynamic perspective of the origin of life as a photochemical dissipative structuring (entropy driven) process, we assess the probability of carbon-based life arising on Earth-like analogues orbiting different main-sequence stellar types (O7 V to M2 V). Using black-body spectra normalized to Earth's solar constant, we calculate surface photon fluxes for an atmosphere like early Archean Earth's in the productive dissipative structuring (P, soft UV-C + UV-B, 205-320 nm) and destructive ionization (D, hard UV-C + EUV, <205 nm) regions. Stationary concentrations of fundamental molecules and times to reach 99% of these are computed for different chemical degradation (e.g., deamination, hydrolysis, oxidation, etc.) rate constants of k = 10^{-7}, 10^{-6}, and 10^{-5} s^{-1}. For a nominal chemical degradation rate constant of k = 10^{-6} s^{-1} (t_{1/2}= 8 days), results show F-, G-, and K-type stars provide the highest stationary concentrations of fundamental molecules and short rise times (weeks to months), while quiescent M-type stars yield extremely low concentrations (~10^{-7} relative to G stars) and require years to reach even these values. Flaring M stars improve stationary concentrations by about an order of magnitude (~10^{-6} relative to G stars) but produce adverse planet surface environments for complex evolution through dissipative structuring. From this non-equilibrium thermodynamic perspective, carbon-based life like Earth's is to be found most probably on F-, G-, and high-mass K-type stars, with intelligent life arising only on G-type stars. Low mass K- and M-dwarfs are highly unlikely to harbor life unless seeded via panspermia. Biosignatures related to the thermodynamic imperative of photon dissipation are proposed.