Physical characterization of double asteroid (617) Patroclus from 2007/2012 mutual events observations

Berthier, J.; Descamps, P.; Vachier, F.; Normand, J.; Maquet, Lucie; Deleflie, F.; Colas, François; Klotz, A.; Teng-Chuen-Yu, J.-P.; Peyrot, A.; Braga-Ribas, F.; Marchis, Franck; Leroy, A.; Bouley, Sylvain; Dubos, G.; Pollock, J. T.; Pauwels, T.; Vingerhoets, P.; Farrell, Jeremiah; Sada, Pedro V.; Reddy, V.; Archer, K.; Hamanowa, Hiromi

doi:10.1016/j.icarus.2020.113990

Cited by 17 publications

(17 citation statements)

References 12 publications

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“…Under the assumption of a rubble-pile structure for JTs, a bulk density of ≈0.9 g cm −3 is required to maintain their structure at that rotation period limit. This value is comparable to the measurements of ∼ 0.8 − 1.0 g cm −3 (Marchis et al 2006;Mueller et al 2010;Buie et al 2015;Berthier et al 2020) from the binary JT system, (617) Patroclus-Menoetius.…”

Section: Discussionsupporting

confidence: 87%

“…Figure 5 shows a plot of spin rate vs lightcurve amplitude for both the FOSSIL JTs and previously measured JTs, along with limits on bulk density calculated from Equation 5. Given the rotation rates measured for the FOSSIL JTs, these objects need a bulk density of at least ≈0.9 g cm −3 , a value consistent with the measurements of ∼ 0.8−1.0 g cm −3 (Marchis et al 2006;Mueller et al 2010;Buie et al 2015;Berthier et al 2020) from the binary JT system, (617) Patroclus-Menoetius system and much higher than that derived from the 5-hr spin-rate limit (i.e., ∼0.5 g cm −3 Ryan et al 2017;Szabó et al 2017Szabó et al , 2020Kalup et al 2021).…”

Section: Resultssupporting

confidence: 72%

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FOSSIL: I. The Spin Rate Limit of Jupiter Trojans

Chang¹,

Chen²,

Fraser³

et al. 2021

Preprint

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Rotation periods of 53 small (diameters 2 km < D < 40 km) Jupiter Trojans (JTs) were derived using the high-cadence light curves obtained by the FOSSIL phase I survey, a Subaru/Hyper Suprime-Cam intensive program. These are the first reported periods measured for JTs with D < 10 km. We found a lower limit of the rotation period near 4 hr, instead of the previously published result of 5 hr (Ryan et al. 2017;Szabó et al. 2017Szabó et al. , 2020 found for larger JTs. Assuming a rubble-pile structure for JTs, a bulk density of ≈0.9 g cm −3 is required to withstand this spin rate limit, consistent with the value ∼ 0.8 − 1.0 g cm −3

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Section: Discussionsupporting

confidence: 87%

Section: Resultssupporting

confidence: 72%

FOSSIL: I. The Spin Rate Limit of Jupiter Trojans

Chang¹,

Chen²,

Fraser³

et al. 2021

Preprint

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“…There are only four known large (diameter ≥100 km) Pand D-type asteroids with satellites: (87) Sylvia, (107) Camilla, (617) Patroclus, and (624) Hektor, with reported densities of 1400 ± 200 kg m −3 (e.g., Berthier et al 2014), 1280 ± 130 kg m −3 (Pajuelo et al 2018), 800 +200 −100 to 1080 ± 330 kg m −3 (Marchis et al 2006;Mueller et al 2010), and 1000 ± 300 kg m −3 (Marchis et al 2014) respectively. Patroclus is a double asteroid with nearly equally-sized 150-100 km components (e.g., Buie et al 2015;Hanuš et al 2017;Berthier et al 2020) and is therefore atypical among asteroids but further strengthens the common origin of P and D asteroids and small KBOs (Nesvorný et al 2018), many of which likely formed as binaries (Fraser et al 2017;Nesvorný et al 2019;Robinson et al 2020). Both Camilla and Sylvia are among the largest asteroids, with diameters above 250 and 280 km, respectively (Carry 2012).…”

Section: Introductionmentioning

confidence: 83%

Evidence for differentiation of the most primitive small bodies

Carry

Vernazza

Vachier

et al. 2021

A&A

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Context. Dynamical models of Solar System evolution have suggested that the so-called P- and D-type volatile-rich asteroids formed in the outer Solar System beyond Neptune’s orbit and may be genetically related to the Jupiter Trojans, comets, and small Kuiper belt objects (KBOs). Indeed, the spectral properties of P- and D-type asteroids resemble that of anhydrous cometary dust. Aims. We aim to gain insights into the above classes of bodies by characterizing the internal structure of a large P- and D-type asteroid. Methods. We report high-angular-resolution imaging observations of the P-type asteroid (87) Sylvia with the Very Large Telescope Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument. These images were used to reconstruct the 3D shape of Sylvia. Our images together with those obtained in the past with large ground-based telescopes were used to study the dynamics of its two satellites. We also modeled Sylvia’s thermal evolution. Results. The shape of Sylvia appears flattened and elongated (a/b ~1.45; a/c ~1.84). We derive a volume-equivalent diameter of 271 ± 5 km and a low density of 1378 ± 45 kg m−3. The two satellites orbit Sylvia on circular, equatorial orbits. The oblateness of Sylvia should imply a detectable nodal precession which contrasts with the fully-Keplerian dynamics of its two satellites. This reveals an inhomogeneous internal structure, suggesting that Sylvia is differentiated. Conclusions. Sylvia’s low density and differentiated interior can be explained by partial melting and mass redistribution through water percolation. The outer shell should be composed of material similar to interplanetary dust particles (IDPs) and the core should be similar to aqueously altered IDPs or carbonaceous chondrite meteorites such as the Tagish Lake meteorite. Numerical simulations of the thermal evolution of Sylvia show that for a body of such a size, partial melting was unavoidable due to the decay of long-lived radionuclides. In addition, we show that bodies as small as 130–150 km in diameter should have followed a similar thermal evolution, while smaller objects, such as comets and the KBO Arrokoth, must have remained pristine, which is in agreement with in situ observations of these bodies. NASA Lucy mission target (617) Patroclus (diameter ≈140 km) may, however, be differentiated.

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“…This dynamical scenario is currently supported by the There are only four known large (diameter ≥100 km) P/D-type asteroids with satellites: (87) Sylvia, (107) Camilla, (617) Patroclus, and (624) Hektor, with reported densities of 1,400 ± 200 kg•m −3 (e.g., Berthier et al, 2014), 1,280 ± 130 kg•m −3 (Pajuelo et al, 2018), 800 +200 −100 to 1080 ± 330 kg•m −3 (Marchis et al, 2006;Mueller et al, 2010), and 1,000 ± 300 kg•m −3 (Marchis et al, 2014) respectively. Patroclus is a double asteroid with nearly equally-sized 150 km-100 km components (e.g., Buie et al, 2015;Hanuš et al, 2017;Berthier et al, 2020) and is therefore atypical among asteroids but further strengthens the common origin of P/D asteroids and small KBOs (Nesvorný et al, 2018), many of which likely formed as binaries (Fraser et al, 2017;Nesvorný et al, 2019;Robinson et al, 2020). Both Camilla and Sylvia are among the largest asteroids, with diameters above 250 and 280 km respectively (Carry, 2012).…”

Section: Introductionmentioning

confidence: 73%

Evidence for differentiation of the most primitive small bodies

Carry,

Vernazza,

Vachier

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Context. Dynamical models of Solar System evolution have suggested that the so-called P-and D-type volatile-rich asteroids formed in the outer Solar System beyond Neptune's orbit and may be genetically related to the Jupiter Trojans, the comets and small Kuiper-belt objects (KBOs). Indeed, the spectral properties of P/D-type asteroids resemble that of anhydrous cometary dust. Aims. We aim at gaining insights into the above classes of bodies by characterizing the internal structure of a large P/D-type asteroid. Methods. We report high-angular-resolution imaging observations of P-type asteroid (87) Sylvia with VLT/SPHERE. These images were used to reconstruct the 3D shape of Sylvia. Our images together with those obtained in the past with large ground-based telescopes were used to study the dynamics of its two satellites. We also model Sylvia's thermal evolution. Results. The shape of Sylvia appears flattened and elongated (a/b∼1.45 ; a/c∼1.84). We derive a volume-equivalent diameter of 271 ± 5 km, and a low density of 1378 ± 45 kg•m −3 . The two satellites orbit Sylvia on circular, equatorial orbits. The oblateness of Sylvia should imply a detectable nodal precession which contrasts with the fully-Keplerian dynamics of its two satellites. This reveals an inhomogeneous internal structure, suggesting that Sylvia is differentiated. Conclusions. Sylvia's low density and differentiated interior can be explained by partial melting and mass redistribution through water percolation. The outer shell would be composed of material similar to interplanetary dust particles (IDPs) and the core similar to aqueously altered IDPs or carbonaceous chondrite meteorites such as the Tagish Lake meteorite. Numerical simulations of the thermal evolution of Sylvia show that for a body of such size, partial melting was unavoidable due to the decay of long-lived radionuclides. In addition, we show that bodies as small as 130-150 km in diameter should have followed a similar thermal evolution, while smaller objects, such as comets and the KBO Arrokoth, must have remained pristine, in agreement with in situ observations of these bodies. NASA Lucy mission target (617) Patroclus (diameter ≈140 km) may, however, be differentiated.

show abstract

Physical characterization of double asteroid (617) Patroclus from 2007/2012 mutual events observations

Cited by 17 publications

References 12 publications

FOSSIL: I. The Spin Rate Limit of Jupiter Trojans

FOSSIL: I. The Spin Rate Limit of Jupiter Trojans

Evidence for differentiation of the most primitive small bodies

Evidence for differentiation of the most primitive small bodies

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