Reference : 3D shape of asteroid (6)~Hebe from VLT/SPHERE imaging: Implications for the origin of...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/212539
3D shape of asteroid (6)~Hebe from VLT/SPHERE imaging: Implications for the origin of ordinary H chondrites
English
Marsset, M. [> >]
Carry, B. [> >]
Dumas, C. [> >]
Hanus, J. [> >]
Viikinkoski, M. [> >]
Vernazza, P. [> >]
Müller, T. G. [> >]
Delbo, M. [> >]
Jehin, Emmanuel [Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa) >]
Gillon, Michaël [Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Origines Cosmologiques et Astrophysiques (OrCa) >]
Grice, J. [> >]
Yang, B. [> >]
Fusco, T. [> >]
Berthier, J. [> >]
Sonnett, S. [> >]
Kugel, F. [> >]
Caron, J. [> >]
Behrend, R. [> >]
1-May-2017
Astronomy and Astrophysics
EDP Sciences
604
A64
Yes (verified by ORBi)
International
0004-6361
1432-0746
Les Ulis
France
[en] Astrophysics - Earth and Planetary Astrophysics
[en] Context. The high-angular-resolution capability of the new-generation ground-based adaptive-optics camera SPHERE at ESO VLT allows us to assess, for the very first time, the cratering record of medium-sized (D~100-200 km) asteroids from the ground, opening the prospect of a new era of investigation of the asteroid belt's collisional history. Aims. We investigate here the collisional history of asteroid (6) Hebe and challenge the idea that Hebe may be the parent body of ordinary H chondrites, the most common type of meteorites found on Earth (~34% of the falls). Methods. We observed Hebe with SPHERE as part of the science verification of the instrument. Combined with earlier adaptive-optics images and optical light curves, we model the spin and three-dimensional (3D) shape of Hebe and check the consistency of the derived model against available stellar occultations and thermal measurements. Results. Our 3D shape model fits the images with sub-pixel residuals and the light curves to 0.02 mag. The rotation period (7.274 47 h), spin (343 deg,+47 deg), and volume-equivalent diameter (193 +/- 6km) are consistent with previous determinations and thermophysical modeling. Hebe's inferred density is 3.48 +/- 0.64 g.cm-3 , in agreement with an intact interior based on its H-chondrite composition. Using the 3D shape model to derive the volume of the largest depression (likely impact crater), it appears that the latter is significantly smaller than the total volume of close-by S-type H-chondrite-like asteroid families. Conclusions. Our results imply that (6) Hebe is not the most likely source of H chondrites. Over the coming years, our team will collect similar high-precision shape measurements with VLT/SPHERE for ~40 asteroids covering the main compositional classes, thus providing an unprecedented dataset to investigate the origin and collisional evolution of the asteroid belt.
Professionals
http://hdl.handle.net/2268/212539
10.1051/0004-6361/201731021
http://adsabs.harvard.edu/abs/2017arXiv170510515M
11 pages, 13 figures, published in A&A

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