2020A&A...641A..39S


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.28CET21:53:55

2020A&A...641A..39S - Astronomy and Astrophysics, volume 641A, 39-39 (2020/9-1)

Rapid elimination of small dust grains in molecular clouds.

SILSBEE K., IVLEV A.V., SIPILA O., CASELLI P. and ZHAO B.

Abstract (from CDS):

We argue that impact velocities between dust grains with sizes of less than ∼0.1µm in molecular cloud cores are dominated by drift arising from ambipolar diffusion. This effect is due to the size dependence of the dust coupling to the magnetic field and the neutral gas. Assuming perfect sticking in collisions up to ≃50m/s, we show that this effect causes rapid depletion of small grains, consistent with starlight extinction and IR and microwave emission measurements, both in the core center (n∼106cm–3) and envelope (n∼104cm–3). The upper end of the size distribution does not change significantly if only velocities arising from this effect are considered. We consider the impact of an evolved grain-size distribution on the gas temperature, and argue that if the depletion of small dust grains occurs as expected from our model, then the cosmic ray ionization rate must be well below 10–16s–1 at a number density of 105cm–3.

Abstract Copyright: © K. Silsbee et al. 2020

Journal keyword(s): dust - extinction - ISM: clouds - evolution

Simbad objects: 3

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Number of rows : 3

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1382 0
2 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 704 0
3 LDN 183 MoC 15 54 12.2 -02 49 42           ~ 690 1

    Equat.    Gal    SGal    Ecl

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2020.11.28-21:53:55

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