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