# Formation of wide binary stars from adjacent cores

## TL;DR

This paper proposes that wide binary stars can form from adjacent prestellar cores in low-density regions, with their formation and survival influenced by environmental density, and confirms this through recent observational data.

## Contribution

It demonstrates that wide binaries originate from adjacent cores in low-density regions and are unlikely to form or persist in dense clusters, supported by recent separation distribution studies.

## Key findings

- Wide binaries are more common in low-density star formation regions.
- Wide binaries do not form or survive in dense clusters.
- More than half of wide pairs contain subsystems, consistent with multiplicity statistics.

## Abstract

Wide gravitationally bound pairs of stars can be formed from adjacent prestellar cores that happen to move slowly enough relative to each other. These binaries are remnants of the primordial clustering. It is shown that the expected fraction of wide bound pairs in low-density star formation regions can be larger than the fraction of wide pairs in the field. On the other hand, wide binaries do not form or survive in dense clusters. Recent works on the separation distribution of young binaries, summarized here, confirm these expectations. Alternative formation mechanisms of wide binaries such as cluster dissolution or unfolding of triple stars cannot explain the large observed fraction of young wide pairs and therefore are not dominant. The fact that more than a half of wide pairs contain subsystems matches the general multiplicity statistics and does not imply that hierarchical multiplicity and wide binaries are genetically related.