CS Lines Profiles in Hot Cores

TL;DR

This theoretical study analyzes CS line profiles in hot cores, showing how different transitions trace various regions and conditions, and highlighting CS as a key dense gas tracer.

Contribution

It provides detailed estimates of CS line fluxes across multiple transitions and links line features to physical conditions and evolutionary stages in hot cores.

Findings

CS(1-0) traces the envelope, higher-J lines trace the ultra-compact core

Peak temperature indicates core temperature

Older cores show stronger self-absorption in CS

Abstract

We present a theoretical study of CS line profiles in archetypal hot cores. We provide estimates of line fluxes from the CS(1-0) to the CS(15-14) transitions and present the temporal variation of these fluxes. We find that \textit{i)} the CS(1-0) transition is a better tracer of the Envelope of the hot core whereas the higher-J CS lines trace the ultra-compact core; \textit{ii)} the peak temperature of the CS transitions is a good indicator of the temperature inside the hot core; \textit{iii)} in the Envelope, the older the hot core the stronger the self-absorption of CS; \textit{iv)} the fractional abundance of CS is highest in the innermost parts of the ultra-compact core, confirming the CS molecule as one of the best tracers of very dense gas.