2022-05-20 Abstract
Title: Deuterium fractionation in starless cores
Speaker: Sheng-Jun Lin
Date: May 20 at 14:30
Location: R124, Physics Building
Abstract:
The ortho-to-para ratio of the most abundant molecule, H2, is an ideal timescale tracer in the star-forming process and is expected to decrease during the core formation. However, it is undetectable with (sub)millimeter observations in cold cores due to a lack of dipole moment. The enhanced deuterium fractionation affected by the o-H2/p-H2 ratio in starless cores, therefore, is a viable proxy. Measuring the deuterium fractionation in starless cores gives us a clue to estimating their lifetime scales to distinguish between different dynamical theories of core formation. To constrain the lifetime scale, we perform chemical modeling of the deuteration profiles across starless cores based on dust extinction measurements from near-infrared observations and non-local thermal equilibrium radiative transfer with multiple line observations including N2H+, N2D+, DCO+, plus H2D+ (110–111) using GBT, JCMT, and the IRAM 30 m telescope. In this talk, I will present the results for two starless cores in the Taurus molecular cloud.