J/A+A/633/A65 (704) Interamnia images (Hanus+, 2020)
(704) Interamnia: a transitional object between a dwarf planet and a typical
irregular-shaped minor body.
Hanus J., Vernazza P., Viikinkoski M., Ferrais M., Rambaux N.,
Podlewska-Gaca E., Drouard A., Jorda L., Jehin E., Carry B., Marsset M.,
Marchis F., Warner B., Behrend R., Asenjo V., Berger N., Bronikowska M.,
Brothers T., Charbonnel S., Colazo C., Coliac J-F., Duard R., Jones A.,
Leroy A., Marciniak A., Melia R., Molina D., Nadolny J., Person M.,
Pejcha O., Riemis H., Shappee B., Sobkowiak K., Sold'an F., Suys D.,
Szakats R., Vantomme J., Birlan M., Berthier J., Bartczak P., Dumas C.,
Dudzin'ski G., Durech J., Castillo-Rogez J., Cipriani F., Fetick R.,
Fusco T., Grice J., Kaasalainen M., Kryszczynska A., Lamy P.,
Michalowski T., Michel P., Santana-Ros T., Tanga P., Vachier F., Vigan A.,
Witasse O., Yang B.
<Astron. Astrophys. 633, A65 (2020)>
=2020A&A...633A..65H 2020A&A...633A..65H (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Minor planets
Keywords: minor planets, asteroids: individual: (704) Interamnia -
methods: observational - techniques: high angular resolution -
techniques: photometric
Abstract:
With an estimated diameter in the 320 to 350km range, (704) Interamnia
is the fifth largest main belt asteroid and one of the few bodies that
fills the gap in size between the four largest bodies with D>400km
(Ceres, Vesta, Pallas and Hygiea) and the numerous smaller bodies with
diameter 200 km. However, despite its large size, little is known
about the shape and spin state of Interamnia and, therefore, about its
bulk composition and past collisional evolution.
We aimed to test at what size and mass the shape of a small body
departs from a nearly ellipsoidal equilibrium shape (as observed in
the case of the four largest asteroids) to an irregular shape as
routinely observed in the case of smaller (D≤200km) bodies.
We observed Interamnia as part of our ESO VLT/SPHERE large program
(ID: 199.C-0074) at thirteen different epochs. In addition, several new
optical lightcurves were recorded. These data, along with stellar
occultation data from the literature, were fed to the All-Data
Asteroid Modeling (ADAM) algorithm to reconstruct the 3D-shape model
of Interamnia and to determine its spin state.
Interamnia's volume-equivalent diameter of 332±6km implies a bulk
density of ρ=1.98±0.68g/cm3, which suggests that Interamnia
- like Ceres and Hygiea - contains a high fraction of water ice,
consistent with the paucity of apparent craters. Our observations
reveal a shape that can be well approximated by an ellipsoid, and that
is compatible with a fluid hydrostatic equilibrium at the
2σlevel.
The rather regular shape of Interamnia implies that the size and mass
limit, under which the shapes of minor bodies with a high amount of
water ice in the subsurface become irregular, has to be searched among
smaller (D≤300km) less massive (m≤3x1019kg) bodies.
Description:
Deconvolved disk-resolved images of asteroid (704) Interamnia from
VLT/SPHERE/Zimpol instrument listed in Table A1.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 106 60 List of VLT/SPHERE disk-resolved images obtained
in the I filter by the ZIMPOL camera
fits/* . 60 Individual fits images, VLT/SPHERE/Zimpol,
Project ID: 199.C-0074
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 23 A23 "datime" Obs.date Observation date
25- 27 I3 s TExp Exposure time
29- 32 F4.2 --- Airmass Airmass
34- 37 F4.2 AU Delta Distance to the Earth
39- 42 F4.2 AU r Distance to the Sun
44- 47 F4.1 deg alpha Phase angle
49- 53 F5.3 arcsec Da Angular diameter
55- 63 F9.5 deg RAdeg Right Ascension of center (J2000)
64- 72 F9.5 deg DEdeg Declination of center (J2000)
74- 80 F7.5 arcsec/pix scale Scale of the image
82- 84 I3 --- Nx Number of pixels along X-axis
86- 88 I3 --- Ny Number of pixels along Y-axis
90- 92 I3 Kibyte size Size of FITS file
94-106 A13 --- FileName Name of FITS file, in subdirectory fits
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Acknowledgements:
Josef Hanus, hanus.home(at)gmail.com
(End) Patricia Vannier [CDS] 02-Dec-2019