Abstract.
This paper presents the results of a Ph.D thesis emphasizing the
studies of various characteristics of Young Stellar Objects (YSOs)
and their environment. The main objective of the thesis is to study
the effects of mechanical and radiative feedback of massive stars on
their surroundings including triggered star formation in Cometary
Globules (CGs) and Bright-Rimmed Clouds (BRCs) situated at the
borders of Galactic HII regions and time dependent interaction of
Pre-Main Sequence (PMS) stars with their circumstellar environment
through accretion and outflow processes. Some of the important
results of this thesis are (i) star formation in BRC SFO~38 is
triggered by massive OB type stars in HII region IC~1396 (ii)
distribution of CGs at the border of HII region Gum~Nebula is
shaped by photoevaporation powered by UV radiation of massive stars
in Vela~OB2 association (iii) interaction of Herbig Ae star V351~Ori
with its circumstellar environment is time-dependent and episodic in
nature. Dynamic magnetospheric accretion and disk wind emerge as the
most satisfactory model for interpreting the observed line profile
variations of V351~Ori. The full version of the thesis is available
from the Indian Institute of Astrophysics Repository webpage:
http://prints.iiap.res.in/handle/2248/5529
Key words: stars: formation, pre-main-sequence -- ISM: HII
regions, clouds