University of Louisville
Infall as a Function of Position and Molecular Tracer in L1544 and L694
Institution
University of Louisville
Faculty Advisor/ Mentor
Gerard Williger; Scott Schnee; Tyler Bourke; Rachel Friesen
Abstract
Stars form within dense, cold, and compact regions of gas and dust known as prestellar cores. When the inward force of gravity overcomes the outward push of the internal pressure of these systems, they begin to collapse and a new star can be born. The standard model of core collapse suggests that this process works from the inside and moves outwards, with the fastest motions at the center. The relative abundances of many molecules also vary within cores, with certain molecules found only in specific regions characterized by narrow ranges of temperature and density. These characteristics lead to the hypothesis that the observed infall speeds in starless cores (i.e. how fast they are collapsing) depend on both the position of the observations and the molecular tracer chosen. Although surveys of infall motions in dense cores have been carried out for years, very few surveys have been awarded enough time to map infall across cores using multiple molecules as tracers. To fill this gap, we present IRAM 30 meter telescope maps of N2H+(1-0), DCO+(2-1), DCO+(3-2) and HCO+(3-2) towards two prestellar cores (L1544 and L694). We find that the measured infall velocity varies as a function of position across each core and varies with the choice of molecular line, likely as a result of radial variations in core chemistry and dynamics.
Infall as a Function of Position and Molecular Tracer in L1544 and L694
Stars form within dense, cold, and compact regions of gas and dust known as prestellar cores. When the inward force of gravity overcomes the outward push of the internal pressure of these systems, they begin to collapse and a new star can be born. The standard model of core collapse suggests that this process works from the inside and moves outwards, with the fastest motions at the center. The relative abundances of many molecules also vary within cores, with certain molecules found only in specific regions characterized by narrow ranges of temperature and density. These characteristics lead to the hypothesis that the observed infall speeds in starless cores (i.e. how fast they are collapsing) depend on both the position of the observations and the molecular tracer chosen. Although surveys of infall motions in dense cores have been carried out for years, very few surveys have been awarded enough time to map infall across cores using multiple molecules as tracers. To fill this gap, we present IRAM 30 meter telescope maps of N2H+(1-0), DCO+(2-1), DCO+(3-2) and HCO+(3-2) towards two prestellar cores (L1544 and L694). We find that the measured infall velocity varies as a function of position across each core and varies with the choice of molecular line, likely as a result of radial variations in core chemistry and dynamics.