We present results of our $R-$band polarimetry of a cometary globule, LBN 437 (Gal96-15, $ell$ $=$ 96$degree$, textit{b} $=-15degree$), to study magnetic field geometry of the cloud. We estimated a distance of $360pm65$ pc to LBN 437 (also one additi
onal cloud, CB 238) using near-IR photometric method. Foreground contribution to the observed polarisation values was subtracted by making polarimetric observations of stars that are located in the direction of the cloud and with known distances from the Hipparcos parallax measurements. The magnetic field geometry of LBN 437 is found to follow the curved shape of the globule head. This could be due to the drag that the magnetic field lines could have experienced because of the ionisation radiation from the same exciting source that caused the cometary shape of the cloud. The orientation of the outflow from the Herbig A4e star, LkH$alpha$ 233 (or V375 Lac), located at the head of LBN 437, is found to be parallel to both the initial (prior to the ionising source was turned on) ambient magnetic field (inferred from a star HD 214243 located just in front of the cloud) and the Galactic plane.
Here we examine the evolution of irradiated clouds using the Smoothed Particle Hydrodynamics ({small SPH}) algorithm coupled with a ray-tracing scheme that calculates the position of the ionisation-front at each timestep. We present results from simu
lations performed for three choices of {small IR}-flux spanning the range of fluxes emitted by a typical {small B}-type star to a cluster of {small OB}-type stars. The extent of photo-ablation, of course, depends on the strength of the incident flux and a strong flux of {small IR} severely ablates a {small MC}. Consequently, the first star-formation sites appear in the dense shocked layer along the edges of the irradiated cloud. Radiation-induced turbulence readily generates dense filamentary structure within the photo-ablated cloud although several new star-forming sites also appear in some of the densest regions at the junctions of these filaments. Prevalent physical conditions within a {small MC} play a crucial role in determining the mode, i.e., filamentary as compared to isolated pockets, of star-formation, the timescale on which stars form and the distribution of stellar masses. The probability density functions ({small PDF}s) derived for irradiated clouds in this study are intriguing due to their resemblance with those presented in a recent census of irradiated {small MC}s. Furthermore, irrespective of the nature of turbulence, the protostellar mass-functions({small MF}s) derived in this study follow a power-law distribution. When turbulence within the cloud is driven by a relatively strong flux of {small IR} such as that emitted by a massive {small O}-type star or a cluster of such stars, the {small MF} approaches the canonical form due to Salpeter, and even turns-over for protostellar masses smaller than $sim$0.2 M$_{odot}$.
