(704) Interamnia: a transitional object between a dwarf planet and a typical irregular-shaped minor body
| Type of publication: | Article |
| Citation: | |
| Publication status: | Published |
| Journal: | Astronomy and Astrophysics |
| Volume: | 633 |
| Year: | 2020 |
| Month: | jan |
| Pages: | A65 |
| ISSN: | 0004-6361 |
| URL: | https://ui.adsabs.harvard.edu/... |
| Abstract: | Context. With an estimated diameter in the 320-350 km range, (704) |
| Userfields: | ={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, > 400 km (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. Aims: 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 ≤ 200 km) bodies. Methods: 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, algorithm to reconstruct the 3D-shape model of Interamnia and to, determine its spin state. Results: Interamnia's volume-equivalent, diameter of 332 ± 6 km implies a bulk density of ρ = 1.98 ± 0.68 g, 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 2σ level. Conclusions: 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 ≤ 300, km) less massive (m ≤ 3 × 1019 kg) bodies. The reduced, images are only available at the CDS via anonymous ftp to |
| Keywords: | asteroids: individual: (704) Interamnia, Astrophysics - Earth and Planetary Astrophysics, methods: observational, minor planets, techniques: high angular resolution, techniques: photometric |
| Authors | |
| Added by: | [JoH] |
| Total mark: | 0 |
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