Star Forming Regions

TL;DR

This paper reviews how X-ray observations from past and current observatories have advanced understanding of star-forming regions and young stellar objects, highlighting key findings and future prospects.

Contribution

It summarizes historical and recent X-ray observational results on YSOs and discusses future directions with next-generation X-ray telescopes.

Findings

YSOs emit X-rays up to 10^4 times solar luminosity.

X-ray emission from Class I YSOs originates from hot, optically thin plasma.

X-ray observations have become essential in studying star formation processes.

Abstract

Since the '80s the \textit{Einstein} observatory has shown the Young Stellar Objects (YSOs), emit X-rays with luminosities, in the 0.3--8 keV bandpass, up to $\rm 10^3$--$\rm 10^4$ times than the Sun and that the X-ray emission is highly variable. ROSAT has confirmed the pervasiveness of X-ray emission from YSOs and ASCA has provided evidence that the emission of Class I YSOs is largely originating from optical thin-plasma at temperature of 1-50 $\times 10^6$ K. These intrinsic, unexpected, properties and the transformational capabilities of the \textit{Chandra} and \textit{XMM-Newton} observatories has made X-rays a powerful tool to trace the star formation process up to distance of a few kpc around the Sun. Starting from the early evidences of the '80s and the intriguing questions they raised, I will summarize the results obtained and how they have influenced our current understanding of physical processes at work and I will discuss some of the still open issues and some of the likely avenues that next generation X-ray observatory will open.