Asteroid (16) Psyche's primordial shape: A possible Jacobi ellipsoid

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F20%3A10421671" target="_blank" >RIV/00216208:11320/20:10421671 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=_wJ2HPMyYI" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=_wJ2HPMyYI</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202038100" target="_blank" >10.1051/0004-6361/202038100</a>

Result language

angličtina

Original language name

Asteroid (16) Psyche's primordial shape: A possible Jacobi ellipsoid

Original language description

Context. Asteroid (16) Psyche is the largest M-type asteroid in the main belt and the target of the NASA Psyche mission. It is also the only asteroid of this size (D&gt; 200 km) known to be metal rich. Although various hypotheses have been proposed to explain the rather unique physical properties of this asteroid, a perfect understanding of its formation and bulk composition is still missing.Aims. We aim to refine the shape and bulk density of (16) Psyche and to perform a thorough analysis of its shape to better constrain possible formation scenarios and the structure of its interior.Methods. We obtained disk-resolved VLT/SPHERE/ZIMPOL images acquired within our ESO large program (ID 199.C-0074), which complement similar data obtained in 2018. Both data sets offer a complete coverage of Psyche&apos;s surface. These images were used to reconstruct the three-dimensional (3D) shape of Psyche with two independent shape modeling algorithms (MPCD and ADAM). A shape analysis was subsequently performed, including a comparison with equilibrium figures and the identification of mass deficit regions.Results. Our 3D shape along with existing mass estimates imply a density of 4.20 0.60 g cm(-3), which is so far the highest for a solar system object following the four telluric planets. Furthermore, the shape of Psyche presents small deviations from an ellipsoid, that is, prominently three large depressions along its equator. The flatness and density of Psyche are compatible with a formation at hydrostatic equilibrium as a Jacobi ellipsoid with a shorter rotation period of similar to 3h. Later impacts may have slowed down Psyche&apos;s rotation, which is currently similar to 4.2 h, while also creating the imaged depressions.Conclusions. Our results open the possibility that Psyche acquired its primordial shape either after a giant impact while its interior was already frozen or while its interior was still molten owing to the decay of the short-lived radionuclide Al-26.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

<a href="/en/project/GA18-09470S" target="_blank" >GA18-09470S: Shape models of large asteroids based on VLT/SPHERE data</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy &amp; Astrophysics

ISSN

0004-6361

e-ISSN

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Volume of the periodical

638

Issue of the periodical within the volume

červen

Country of publishing house

FR - FRANCE

Number of pages

9

Pages from-to

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UT code for WoS article

000550003500002

EID of the result in the Scopus database

2-s2.0-85087885981