A star forming ring around Kappa Ori 250 pc from the Sun

TL;DR

This study uses X-ray observations to identify young stars in a ring around Kappa Ori, suggesting the ring is a shell swept up by the star, and estimates its distance at 250-280 pc, closer than Orion A.

Contribution

It reveals a star-forming ring around Kappa Ori at 250-280 pc, proposing it as a shell swept up by the star, distinct from Orion A.

Findings

Detected 121 young stellar objects in the ring.

Estimated the ring's distance at 250-280 pc.

Proposed the ring as a shell swept up by Kappa Ori.

Abstract

X-rays are a powerful probe of activity in early stages of star formation. They allow us to identify young stars even after they have lost the IR signatures of circumstellar disks and provide constraints on their distance. Here we report on XMM-Newton observations which detect 121 young stellar objects (YSOs) in two fields between L1641S and $\kappa$ Ori. These observations extend the Survey of Orion A with XMM and Spitzer (SOXS). The YSOs are contained in a ring of gas and dust apparent at millimeter wavelengths, and in far-IR and near-IR surveys. The X-ray luminosity function of the young stellar objects detected in the two fields indicates a distance of 250-280 pc, much closer than the Orion A cloud and similar to distance estimates of $\kappa$ Ori. We propose that the ring is a 5-8 pc diameter shell that has been swept up by $\kappa$ Ori. This ring contains several groups of stars detected by Spitzer and WISE including one surrounding the Herbig Ae/Be stars V1818 Ori. In this interpretation, the $\kappa$ Ori ring is one of several shells swept up by massive stars within the Orion Eridanus Superbubble, and is unrelated to the southern portion of Orion A / L1641 S.