Binary asteroid (31) Euphrosyne: ice-rich and nearly spherical

被引：19

作者：

Yang, B. ^{[1
]}

Hanus, J. ^{[2
]}

Carry, B. ^{[3
]}

Vernazza, P. ^{[4
]}

Broz, M. ^{[2
]}

Vachier, F. ^{[5
]}

Rambaux, N. ^{[5
]}

Marsset, M. ^{[6
]}

Chrenko, O. ^{[2
]}

Sevecek, P. ^{[2
]}

Viikinkoski, M. ^{[7
]}

Jehin, E. ^{[8
]}

Ferrais, M. ^{[4
]}

Podlewska-Gaca, E. ^{[9
]}

Drouard, A. ^{[4
]}

Marchis, F. ^{[10
]}

Birlan, M. ^{[5
,22
]}

Benkhaldoun, Z. ^{[11
]}

Berthier, J. ^{[5
]}

Bartczak, P. ^{[9
]}

Dumas, C. ^{[12
]}

Dudzinski, G. ^{[9
]}

Durech, J. ^{[2
]}

Castillo-Rogez, J. ^{[13
]}

Cipriani, F. ^{[14
]}

Colas, F. ^{[5
]}

Fetick, R. ^{[4
]}

Fusco, T. ^{[4
,15
]}

Grice, J. ^{[3
,16
]}

Jorda, L. ^{[4
]}

Kaasalainen, M. ^{[7
]}

Kryszczynska, A. ^{[9
]}

Lamy, P. ^{[17
,18
]}

Marciniak, A. ^{[9
]}

Michalowski, T. ^{[9
]}

Michel, P. ^{[3
]}

Pajuelo, M. ^{[5
,19
]}

Santana-Ros, T. ^{[20
,21
]}

Tanga, P. ^{[3
]}

Vigan, A. ^{[4
]}

Witasse, O. ^{[14
]}

机构：

[1] European Southern Observ ESO, Alonso de Cordova 3107, Santiago 1900, Chile

[2] Charles Univ Prague, Fac Math & Phys, Inst Astron, V Holesovickach 2, Prague 18000, Czech Republic

[3] Univ Cote Azur, Observ Cote Azur, CNRS, Lab Lagrange, Nice, France

[4] Aix Marseille Univ, CNRS, LAM, Lab Astrophys Marseille, Marseille, France

[5] Univ Lille, PSL Res Univ, Sorbonne Univ, IMCCE,Observ Paris,CNRS,UPMC Univ Paris 06, Lille, France

[6] MIT, Dept Earth Atmospher & Planetary Sci, 77 Massachusetts Ave, Cambridge, MA 02139 USA

[7] Tampere Univ, Math & Stat, Tampere 33014, Finland

[8] Univ Liege, Space Sci Technol & Astrophys Res Inst, Allee 6 Aout 17, B-4000 Liege, Belgium

[9] Adam Mickiewicz Univ, Fac Phys, Astron Observ Inst, Ul Sloneczna 36, PL-60286 Poznan, Poland

[10] Carl Sagan Ctr, SETI Inst, 189 Bernado Ave, Mountain View, CA 94043 USA

[11] Cadi Ayyad Univ, Oukaimeden Observ, High Energy Phys & Astrophys Lab, Marrakech, Morocco

[12] Thirty Meter Telescope, 100 West Walnut St,Suite 300, Pasadena, CA 91124 USA

[13] CALTECH, Jet Prop Lab, 4800 Oak Grove Dr, Pasadena, CA 91109 USA

[14] European Space Agcy, ESTEC Sci Support Off, Keplerlaan 1, NL-2200 AG Noordwijk, Netherlands

[15] Univ Paris Saclay, ONERA, DOTA, F-91123 Palaiseau, France

[16] Open Univ, Sch Phys Sci, Milton Keynes MK7 6AA, Bucks, England

[17] CNRS, Lab Atmospheres Milieux & Observat Spatiales, St Quentin En Yveline, Guyancourt, France

[18] Univ Versailles St Quentin En Yveline, St Quentin En Yveline, Guyancourt, France

[19] Pontificia Univ Catolica Peru, Dept Ciencias, Secc Fis, Apartado 1761, Lima, Peru

[20] Univ Alicante, Dept Fis Ingn Sistemas & Teoria Senal, Alicante, Spain

[21] Univ Barcelona IEEC UB, Inst Ciencies Cosmos ICCUB, E-08028 Barcelona, Spain

[22] Romanian Acad, Astron Inst, 5,Cutitul Argint St, Bucharest 040557, Romania

来源：

ASTRONOMY & ASTROPHYSICS | 2020年 / 641卷

基金：

美国国家航空航天局;

关键词：

techniques: high angular resolution; methods: observational; minor planets; asteroids: individual: (31) Euphrosyne; asteroids:; general; ROTATIONAL PROPERTIES; DYNAMICAL PROPERTIES; SHAPE MODEL; BELT; FAMILIES; DENSITY; SYSTEMS;

D O I：

10.1051/0004-6361/202038372

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

Aims. Asteroid (31) Euphrosyne is one of the biggest objects in the asteroid main belt and it is also the largest member of its namesake family. The Euphrosyne family occupies a highly inclined region in the outer main belt and contains a remarkably large number of members, which is interpreted as an outcome of a disruptive cratering event. Methods. The goals of this adaptive-optics imaging study are threefold: to characterize the shape of Euphrosyne, to constrain its density, and to search for the large craters that may be associated with the family formation event. Results. We obtained disk-resolved images of Euphrosyne using SPHERE/ZIMPOL at the ESO 8.2 m VLT as part of our large program (ID: 199.C-0074, PI: Vernazza). We reconstructed its 3D shape via the ADAM shape modeling algorithm based on the SPHERE images and the available light curves of this asteroid. We analyzed the dynamics of the satellite with the Genoid meta-heuristic algorithm. Finally, we studied the shape of Euphrosyne using hydrostatic equilibrium models. Conclusions. Our SPHERE observations show that Euphrosyne has a nearly spherical shape with the sphericity index of 0.9888 and its surface lacks large impact craters. Euphrosyne's diameter is 268 +/- 6 km, making it one of the top ten largest main belt asteroids. We detected a satellite of Euphrosyne - S/2019 (31) 1 - that is about 4 km across, on a circular orbit. The mass determined from the orbit of the satellite together with the volume computed from the shape model imply a density of 1665 +/- 242 kg m(-3), suggesting that Euphrosyne probably contains a large fraction of water ice in its interior. We find that the spherical shape of Euphrosyne is a result of the reaccumulation process following the impact, as in the case of (10) Hygiea. However, our shape analysis reveals that, contrary to Hygiea, the axis ratios of Euphrosyne significantly differ from those suggested by fluid hydrostatic equilibrium following reaccumulation.

引用

页数：9

共 4 条

[1] Asteroid (4337) Arecibo: Two ice-rich bodies forming a binary
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[2] On the Structure and Long-term Evolution of Ice-rich Bodies
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[3] Evidence of Ice-Rich Layered Deposits in the Medusae Fossae Formation of Mars
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[4] Analysis of equilibria in the doubly synchronous binary asteroid systems concerned with non-spherical shape
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Astrodynamics, 2018, 2 (02) : 133 - 146

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