Query : 2014A&A...568A.103K

2014A&A...568A.103K - Astronomy and Astrophysics, volume 568A, 103-103 (2014/8-1)

Effect of dust grain porosity on the appearance of protoplanetary disks.


Abstract (from CDS):

We theoretically analyze protoplanetary disks consisting of porous dust grains. In the analysis of observations of protoplanetary disks the dust phase is often assumed to consist of spherical grains, allowing one to apply the Mie scattering formalism. However, in reality, the shape of dust grains is expected to deviate strongly from that of a sphere. We investigate the influence of porous dust grains on the temperature distribution and observable appearance of protoplanetary disks for dust grain porosities of up to 60%. We performed radiative transfer modeling to simulate the temperature distribution, spectral energy distribution, and spatially resolved intensity and polarization maps. The optical properties of porous grains were calculated using the method of discrete dipole approximation. Grain porosity has a strong influence on the spectral energy distribution and scattered-light maps of protoplanetary disks. The flux in the optical wavelength range is for porous grains higher than for compact, spherical grains. The profile of the silicate peak at 9.7µm strongly depends on the degree of grain porosity. The temperature distribution shows significant changes in the direction perpendicular to the midplane. Moreover, simulated polarization maps reveal an increase of the polarization degree by a factor of about four when porous grains are considered, regardless of the disk inclination. The polarization direction is reversed in selected disk regions, depending on the wavelength, grain porosity, and disk inclination. We discuss several possible explanations of this effect and find that multiple scattering explains the effect best. Porosity influences the observable appearance of protoplanetary disks. In particular, the polarization reversal shows a dependence on grain porosity. The physical conditions within the disk are altered by porosity, which might have an effect on the processes of grain growth and disk evolution.

Abstract Copyright:

Journal keyword(s): protoplanetary disks - stars: pre-main sequence - circumstellar matter - planets and satellites: formation - radiative transfer

Simbad objects: 7

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Number of rows : 7
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 IRAS 04158+2805 Y*O 04 18 58.1336295120 +28 12 23.355499140           M5.25 97 0
2 V* V1213 Tau Or* 04 31 37.5055489536 +18 12 24.383952396           K7 548 0
3 V* HK Tau TT* 04 31 50.5715875272 +24 24 17.775307548 16.81 16.689 15.292     M0.5 329 1
4 IRAS 04302+2247 Y*O 04 33 16.50096 +22 53 20.4000           ~ 164 0
5 V* HV Tau C TT* 04 38 35.5125950280 +26 10 41.316576204         14.90 K6 93 0
6 LDN 1439 DNe 05 00 09 +52 04.9           ~ 84 0
7 THA 15-12 Or* 15 56 09.2066646912 -37 56 06.126118692   13.12 11.93 11.45   M0e 362 0

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