TY  - JOUR
T1  - The impact crater at the origin of the Julia family detected with VLT/SPHERE?
A1  - Vernazza, P.
A1  - Brož, M.
A1  - Drouard, A.
A1  - Hanuš, J.
A1  - Viikinkoski, M.
A1  - Marsset, M.
A1  - Jorda, L.
A1  - Fetick, R.
A1  - Carry, B.
A1  - Marchis, F.
A1  - Birlan, M.
A1  - Fusco, T.
A1  - Santana-Ros, T.
A1  - Podlewska-Gaca, E.
A1  - Jehin, E.
A1  - Ferrais, M.
A1  - Bartczak, P.
A1  - Dudziński, G.
A1  - Berthier, J.
A1  - Castillo-Rogez, J.
A1  - Cipriani, F.
A1  - Colas, F.
A1  - Dumas, C.
A1  - Ďurech, J.
A1  - Kaasalainen, M.
A1  - Kryszczynska, A.
A1  - Lamy, P.
A1  - Le Coroller, H.
A1  - Marciniak, A.
A1  - Michalowski, T.
A1  - Michel, P.
A1  - Pajuelo, M.
A1  - Tanga, P.
A1  - Vachier, F.
A1  - Vigan, A.
A1  - Warner, B.
A1  - Witasse, O.
A1  - Yang, B.
A1  - Asphaug, E.
A1  - Richardson, D. C.
A1  - Ševeček, P.
A1  - Gillon, M.
A1  - Benkhaldoun, Z.
JA  - Astronomy and Astrophysics
Y1  - 2018
VL  - 618
SP  - A154
SN  - 0004-6361
UR  - https://ui.adsabs.harvard.edu/abs/2018A&A...618A.154V
KW  - asteroids: individual: (89) Julia
KW  - methods: numerical
KW  - methods: observational
KW  - minor planets
KW  - techniques: high angular resolution
N2  - Context. The vast majority of the geophysical and geological constraints
M1  - ={(e.g.
M1  -  internal structure
M1  -  cratering history) for main-belt asteroids
M1  -  have so far been obtained via dedicated interplanetary missions (e.g.
M1  -  ESA Rosetta
M1  -  NASA Dawn). The high angular resolution of SPHERE/ZIMPOL
M1  -  the new-generation visible adaptive-optics camera at ESO VLT
M1  -  implies
M1  -  that these science objectives can now be investigated from the ground
M1  -  for a large fraction of D ≥ 100 km main-belt asteroids. The sharp images
M1  -  acquired by this instrument can be used to accurately constrain the
M1  -  shape and thus volume of these bodies (hence density when combined with
M1  -  mass estimates) and to characterize the distribution and topography of D
M1  -  ≥ 30 km craters across their surfaces. <BR /> Aims: Here
M1  -  via several
M1  -  complementary approaches
M1  -  we evaluated the recently proposed hypothesis
M1  -  that the S-type asteroid (89) Julia is the parent body of a small
M1  -  compact asteroid family that formed via a cratering collisional event.
M1  -  <BR /> Methods: We observed (89) Julia with VLT/SPHERE/ZIMPOL throughout
M1  -  its rotation
M1  -  derived its 3D shape
M1  -  and performed a reconnaissance and
M1  -  characterization of the largest craters. We also performed numerical
M1  -  simulations to first confirm the existence of the Julia family and to
M1  -  determine its age and the size of the impact crater at its origin.
M1  -  Finally
M1  -  we utilized the images/3D shape in an attempt to identify the
M1  -  origin location of the small collisional family. <BR /> Results: On the
M1  -  one hand
M1  -  our VLT/SPHERE observations reveal the presence of a large
M1  -  crater (D 75 km) in Julia's southern hemisphere. On the other hand
M1  -  our
M1  -  numerical simulations suggest that (89) Julia was impacted 30-120 Myrs
M1  -  ago by a D 8 km asteroid
M1  -  thereby creating a D ≥ 60 km impact crater at
M1  -  the surface of Julia. Given the small size of the impactor
M1  -  the
M1  -  obliquity of Julia and the particular orientation of the family in the
M1  -  (a
M1  - i) space
M1  -  the imaged impact crater is likely to be the origin of the
M1  -  family. <BR /> Conclusions: New doors into ground-based asteroid
M1  -  exploration
M1  -  namely
M1  -  geophysics and geology
M1  -  are being opened thanks to
M1  -  the unique capabilities of VLT/SPHERE. Also
M1  -  the present work may
M1  -  represent the beginning of a new era of asteroid-family studies. In the
M1  -  fields of geophysics
M1  -  geology
M1  -  and asteroid family studies
M1  -  the future
M1  -  will only get brighter with the forthcoming arrival of 30-40 m class
M1  -  telescopes like ELT
M1  -  TMT
M1  -  and GMT. <P />Based on observations made with
M1  -  ESO Telescopes at the Paranal Observatory under program ID 199.C-0074
M1  -  (PI: P. Vernazza).The reduced images are only available available at the
M1  -  CDS via anonymous ftp to <A
M1  -  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A
M1  -  href="http://cdsarc.u-strasbg.fr">http://130.79.128.5</A>) or via <A
M1  -  href="http://cdsarc.u-strasbg.fr/viz-
M1  -  bin/qcat?J/A+A/618/A154">http://cdsarc.u-strasbg.fr/viz-
M1  -  bin/qcat?J/A+A/618/A154</A>
M1  -  10.1051/0004-6361/201833477}
ER  -