The role of protostellar heating in star formation
Jones, Michael Oliver
Date: 18 June 2018
Publisher
University of Exeter
Degree Title
PhD in Physics
Abstract
Previous studies have shown that thermal feedback from protostars plays a key role in the
process of low-mass star formation. In this thesis, we explore the effects of protostellar
heating on the formation of stellar clusters. We describe new methods for modelling protostellar
accretion luminosities and protostellar evolution in ...
Previous studies have shown that thermal feedback from protostars plays a key role in the
process of low-mass star formation. In this thesis, we explore the effects of protostellar
heating on the formation of stellar clusters. We describe new methods for modelling protostellar
accretion luminosities and protostellar evolution in calculations of star formation.
We then present results of a series of numerical simulations of stellar cluster formation
which include these effects, and examine their impact.
We begin by investigating the dependence of stellar properties on the initial density
of molecular clouds. We find that the dependence of the median stellar mass on the
initial density of the cloud is weaker than the dependence of the thermal Jeans mass when
radiative effects are included. We suggest that including protostellar accretion luminosities
and protostellar evolution may weaken this dependence further, and may account for the
observed invariance of the median stellar mass in Galactic star-forming regions.
Next, we investigate the effects of including accretion feedback from sink particles
on the formation of small stellar groups. We find that including accretion feedback in
calculations suppresses fragmentation even further than calculations that only include
radiative transfer within the gas. Including feedback also produces a higher median stellar
mass, which is insensitive to the sink particle accretion radius used.
Finally, we compare calculations of small stellar clusters which model the evolution of
protostars using a live stellar model with those which use a fixed stellar structure. We find
that the dynamics of the clusters are primarily determined by the accretion luminosities of
protostars, but that the relative effects of protostellar evolution depend on the accretion
rate and advection of energy into the protostar. We also demonstrate how such calculations
may be used to study the properties of young stellar populations.
Doctoral Theses
Doctoral College
Item views 0
Full item downloads 0