Investigation of Rocket Effect in BRC 18 using Gaia EDR3
  Bright-rimmed clouds (BRCs) are ideal candidates to study radiation-driven
implosion mode of star formation as they are potential sites of triggered star
formation, located at the edges of H{\sc ii} regions, showing evidence of
ongoing star formation processes. BRC 18 is located towards the eastern edge of
relatively closer ($\sim$400 pc) H{\sc ii} region excited by $\lambda$ Ori. We
made R-band polarimetric observations of 17 candidate young stellar objects
(YSOs) located towards BRC 18 to investigate any preferred orientation of the
discs with respect to the ambient magnetic field and the direction of energetic
photons from $\lambda$ Ori. We found that the discs are oriented randomly with
respect to the projected magnetic field. Using distances and proper motions
from the \textit{Gaia} EDR3 of the candidate YSOs, we investigated the possible
acceleration of BRC 18, away from $\lambda$ Ori due to the well known "Rocket
Effect", by assuming that both the candidate YSOs and BRC 18 are kinematically
coupled. The relative proper motions of the candidate YSOs are found to show a
trend of moving away from $\lambda$ Ori. We computed the offset between the
angle of the direction of the ionization front and the relative proper motion
of the candidate YSOs and found it to lie close to being parallel to each
other. Additionally, we found 12 sources that are comoving with the known
candidate YSOs towards BRC 18. These comoving sources are most likely to be
young and are missed in previous surveys conducted to identify potential YSOs
of the region.
