Diagnosing Triggered Star Formation in the Galactic H II region Sh 2-142
  Stars are formed by gravitational collapse, spontaneously or, in some cases
under the constructive influence of nearby massive stars, out of molecular
cloud cores. Here we present an observational diagnosis of such triggered
formation processes in the prominent \ion{H}{2} region Sh\,2-142, which is
associated with the young star cluster NGC\,7380, and with some bright-rimmed
clouds as the signpost of photoionization of molecular cloud surfaces. Using
near- (2MASS) and mid-infrared (WISE) colors, we identified candidate young
stars at different evolutionary stages, including embedded infrared sources
having spectral energy distributions indicative of active accretion. We have
also used data from our optical observations to be used in SEDs, and from Gaia
EDR3 to study the kinematics of young objects. With this young stellar sample,
together with the latest CO line emission data (spectral resolution $\sim
0.16$~km~s$^{-1}$, sensitivity $\sim 0.5$~K), a positional and ageing sequence
relative to the neighboring cloud complex, and to the bright-rimmed clouds, is
inferred. The propagating stellar birth may be responsible, at least partially,
for the formation of the cluster a few million years ago, and for the ongoing
activity now witnessed in the cloud complex.
