J/A+A/630/A142 HR4796 debris disk Qphi and Uphi images (Olofsson+, 2019)
Dust production in the debris disk around HR 4796 A.
Olofsson J., Milli J., Thebault P., Kral Q., Menard F., Janson M.,
Augereau J.-C., Bayo A., Beamin J.C., Henning Th., Iglesias D.,
Kennedy G.M., Montesinos M., Pawellek N., Schreiber M.R., Zamora C.,
Carbillet M., Feautrier P., Fusco T., Madec F., Rabou P., Sevin A.,
Szulagyi J., Zurlo A.
<Astron. Astrophys. 630, A142 (2019)>
=2019A&A...630A.142O 2019A&A...630A.142O (SIMBAD/NED BibCode)
ADC_Keywords: Stars, A-type ; Polarization
Keywords: circumstellar matter - techniques: high angular resolution
Abstract:
Debris disks are the natural by-products of the planet formation
process. Scatte red or polarized light observations are mostly
sensitive to small dust grains that are released from the grinding
down of bigger planetesimals. High angular resolution observations at
optical wavelengths can provide key constraints on the radial and
azimuthal distribution of the small dust grains. These constraints can
help us better understand where most of the dust grains are released
upon collisions. We present SPHERE/ZIMPOL observations of the debris
disk around HR 4796A, and model the radial profiles along several
azimuthal angles of the disk with a code that accounts for the effect
of stellar radiation pressure. This enables us to derive an
appropriate description for the radial and azimuthal distribution of
the small dust grains. Even though we only model the radial profiles
along (or close to) the semi-major axis of the disk, our best-fit
model is not only in good agreement with our observations but also
with previously published datasets (from near-IR to sub-mm
wavelengths). We find that the reference radius is located at
76.4±0.4au, and the disk has an eccentricity of
0.076-0.010+0.016, with the pericenter located on the front side
of the disk (north of the star). We find that small dust grains must
be preferentially released near the pericenter to explain the observed
brightness asymmetry. Even though parent bodies spend more time near
the apocenter, the brightness asymmetry implies that collisions happen
more frequently near the pericenter of the disk. Our model can
successfully reproduce the shape of the outer edge of the disk,
without having to invoke an outer planet shepherding the debris disk.
With a simple treatment of the effect of the radiation pressure, we
conclude that the parent planetesimals are located in a narrow ring of
about 3.6au in width.
Description:
The two fits files contain the reduced Qphi and Uphi SPHERE/ZIMPOL
observations as published in the paper. The target was observed in the
P2 polarimetric mode, and the observations took place on the
2016-05-24. There is only one PrimaryHDU per fits file, with
dimensions (512, 512). The headers contain basic information, such as
the coordinates, the reference pixel, and the size of the pixels in
units of degrees. The observations are not flux calibrated.
Objects:
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RA (2000) DE Designation(s)
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12 36 01.03 -39 52 10.2 HR 4796 = HD 109573
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 92 2 List of fits files
fits/* . 2 Individual fits files
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 31 I4 Kibyte size Size of FITS file
33- 48 A16 --- FileName Name of FITS file, in subdirectory fits
50- 92 A43 --- Title Title of the FITS file
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Acknowledgements:
Johan Olofsson, johan.olofsson(at)uv.cl
(End) Patricia Vannier [CDS] 28-Aug-2019