Abstract
It is shown here how new experimental data, for the electrical properties of solid CO, can be used to fill important gaps in our understanding of the evolution of pre-stellar cores. Dust grains with a mantle of CO lead to a reduction in the degree of ionization in these cores by a factor of between 5 and 6. The lifetimes for expulsion of magnetic fields from cores, a process generally necessary for gravitational collapse, are reduced from current estimates of several Myr, by a similar factor. This removes a major inconsistency, since lifetimes now tally with typical ages of pre-stellar cores of a few hundred thousand to one million years, derived from observations. With the reduced timescales, cores also escape disruption by Galactic supernova remnants. Our results provide a natural mechanism for the generation of so-called magnetically supercritical cores, in which the magnetic field alone cannot prevent gravitational collapse. In addition we find a minimum value for the density of pre-stellar cores of ≥1.1±0.1×104 H2 cm-3, in agreement with observations.
Original language | English |
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Article number | 1 |
Number of pages | 6 |
Journal | Astrophysical Journal |
Volume | 832 |
Issue number | 1 |
Early online date | 10 Nov 2016 |
DOIs | |
Publication status | Published - 20 Nov 2016 |
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Martin R. S. McCoustra
Person: Academic (Research & Teaching)