The Formation of Population III Binaries from Cosmological Initial Conditions

TL;DR

This study uses cosmological simulations to show that the first stars, previously thought to form in isolation, can actually form as binary systems due to fragmentation of massive gas clumps in the early universe.

Contribution

It demonstrates that Population III stars can form as binaries from cosmological initial conditions, challenging the idea that they only form in isolation.

Findings

First stars can form as binaries through gas cloud fragmentation.

Massive gas clumps can break into multiple cores in early universe simulations.

Binary systems can continue accreting gas over 10^5 years.

Abstract

Previous high resolution cosmological simulations predict the first stars to appear in the early universe to be very massive and to form in isolation. Here we discuss a cosmological simulation in which the central 50 solar mass clump breaks up into two cores, having a mass ratio of two to one, with one fragment collapsing to densities of 10^{-8} g/cc. The second fragment, at a distance of 800 astronomical units, is also optically thick to its own cooling radiation from molecular hydrogen lines, but is still able to cool via collision-induced emission. The two dense peaks will continue to accrete from the surrounding cold gas reservoir over a period of 10^5 years and will likely form a binary star system.