Submillimeter Emission from Small Dust Grains Orbiting Nearby Stars

The physical and chemical properties of the circumstellar envelopes of evolved stars are strongly affected by the interstellar radiation field. Other sources of UV radiation should be similarly effective, and some examples are nearby stars (including companions), chromospheres, and the central stars of planetary nebulae. We consider the particular case of Alpha Ori, which has a chromosphere and an extended CSE with a small dust to gas ratio. Its properties are dominated by the chromospheric and interstellar radiation fields. The most common species are neutral atoms and first ions, and the electron fraction is high throughout the entire CSE, i.e. at least 10−4. The abundances of neutrals peak in the outer CSE close to where the chromospheric and interstellar radiation fields are equal. An important application is KI, whose density has been measured by scattering. The theory predicts that the slope of the KI density should change from about −1.5 to −3.5 in the outer envelope, the exact values being determined by the temperature distribution. The mass loss rate implied by the KI density is of the order of 4×10−6 M⊙ yr−1.

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PROTOPLANETARY DISK MASSES IN IC348: A RAPID DECLINE IN THE POPULATION OF SMALL DUST GRAINS AFTER 1 Myr

The Astrophysical Journal ◽

10.1088/0004-637x/736/2/135 ◽

2011 ◽

Vol 736 (2) ◽

pp. 135 ◽

Cited By ~ 30

Author(s):

Nicholas Lee ◽

Jonathan P. Williams ◽

Lucas A. Cieza

Keyword(s):

Protoplanetary Disk ◽

Rapid Decline ◽

Dust Grains ◽

Small Dust

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A fast and explicit algorithm for simulating the dynamics of small dust grains with smoothed particle hydrodynamics

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stv996 ◽

2015 ◽

Vol 451 (1) ◽

pp. 813-826 ◽

Cited By ~ 41

Author(s):

Daniel J. Price ◽

Guillaume Laibe

Keyword(s):

Smoothed Particle Hydrodynamics ◽

Dust Grains ◽

Explicit Algorithm ◽

Particle Hydrodynamics ◽

Smoothed Particle ◽

Small Dust

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Observations of Unusually Small Dust Grains in the Coma of Comet Hale‐Bopp C/1995 O1

The Astrophysical Journal ◽

10.1086/319039 ◽

2001 ◽

Vol 549 (1) ◽

pp. 635-646 ◽

Cited By ~ 30

Author(s):

C. G. Mason ◽

R. D. Gehrz ◽

T. J. Jones ◽

C E. Woodward ◽

M. S. Hanner ◽

...

Keyword(s):

Dust Grains ◽

Small Dust

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Rapid elimination of small dust grains in molecular clouds

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038063 ◽

2020 ◽

Vol 641 ◽

pp. A39 ◽

Cited By ~ 1

Author(s):

Kedron Silsbee ◽

Alexei V. Ivlev ◽

Olli Sipilä ◽

Paola Caselli ◽

Bo Zhao

Keyword(s):

Size Distribution ◽

Cosmic Ray ◽

Ionization Rate ◽

Microwave Emission ◽

Dust Grains ◽

Gas Temperature ◽

Neutral Gas ◽

Cloud Cores ◽

The Impact ◽

Small Dust

We argue that impact velocities between dust grains with sizes of less than ∼0.1 μm 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 ≈50 m s−1, 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 ∼ 106 cm−3) and envelope (n ∼ 104 cm−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 10−16 s−1 at a number density of 105 cm−3.

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