The early phase of multiple proto-stellar system emerged from collapse of molecular cloud under various initial thermal states

TL;DR

This study investigates how initial thermal states of molecular clouds influence early proto-stellar structure formation, revealing a temperature-dependent transition from spiral to ring instabilities during collapse.

Contribution

It provides new insights into how initial temperature variations affect the development of instabilities and structures in collapsing molecular clouds.

Findings

Spiral structures form in clouds with initial temperatures below 10K.

Ring structures develop in clouds with initial temperatures above 10K.

A transition from spiral to ring instability occurs at approximately 10K.

Abstract

An attempt is made here to revisit structure formation in a proto-stellar cloud during the early phase of evolution. Molecular cloud subjected to a set of various initial conditions in terms of initial temperature and amplitude of azimuthal density perturbation is investigated numerically. Special emphasis remained on the analysis of ring and spiral type instabilities that have shown dependence on certain initial conditions chosen for a rotating solar mass cloud of molecular hydrogen. Generally, a star forming hydrogen gas is considered to be initially at 10K. We have found that a possible oscillation around this typical value can affect the fate of a collapsing cloud in terms of its evolving structural properties leading to proto-star formation. We explored the initial temperature range of cloud between 8K to 12K and compared physical properties of each within the first phase of proto-star formation. We suggest that the spiral structures are more likely to form in strongly perturbed molecular cores that initiate their phase of collapse from temperatures below 10K. Whereas, cores with initial temperatures above 10K develop, instead of spiral, a ring type structure which subsequently experiences the fragmentation. A transition from spiral to ring instability can be observed at a typical initial temperature of 10K.