A&A 370, 447-455 (2001)
DOI: 10.1051/0004-6361:20010199
Dynamical modeling of large scale asymmetries in the
Picto ris dust disk
J. C. Augereau1, R. P. Nelson2, A. M. Lagrange1, J. C. B. Papaloizou2 and D. Mouillet1
1 Laboratoire d'Astrophysique de l'Observatoire de Grenoble, Université J. Fourier, CNRS, BP 53, 38041 Grenoble Cedex 9, France
2 Astronomy Unit, School of Mathematical Sciences, Queen Mary & Westfield College, Mile End Road, London E1 4NS, UK
(Received 27 October 2000 / Accepted 19 January 2001)
Abstract
We report a new and complete model of the
Picto ris disk,
which succeeds in accounting for both the surface brightness
distribution, warp characteristics, the outer "butterfly"asymmetry
as observed by HST/STIS in scattered light, as well as the infrared
emission.
Our model includes the presence of a disk of planetesimals extending
out to 120-150 AU, perturbed gravitationally by a giant planet on an
inclined orbit, following the approach of Mouillet et al. (1997b). At any time,
the planetesimal disk is assumed to be the source of a distribution of
grains produced through collisional evolution, with the same initial
orbital parameter distribution. The steady state spatial grain
distribution is found incorporating the effects of radiation pressure
which can cause the distribution of the smallest particles to become
very distended.
With realistic assumptions about the grains' chemical properties, the
modeling confirms the previously evident need for an additional
population of hot grains close to the star, to account for the
12
m fluxes at short distances from the star. It also indicates
that this population cannot explain the outer 12
m flux
distribution when the effects of gravity and radiation pressure
determine the distribution. Very small grains, produced by
collisions among aggregates, are tentatively proposed to account for
this 12
m outer emission.
Key words: stars: cir cum stel lar matter -- stars:
Offprint request: J. C. Augereau, augereau@obs.ujf-grenoble.fr
SIMBAD Objects
© ESO 2001

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