Dynamical evidence for Phobos and Deimos as remnants of a disrupted common progenitor

2021 ◽  
Author(s):  
Amirhossein Bagheri ◽  
Amir Khan ◽  
Michael Efroimsky ◽  
Mikhail Kruglyakov ◽  
Domenico Giardini
Keyword(s):  
Satellite System ◽  
Physical Libration ◽  
Tidal Evolution ◽  
Tidal Dissipation ◽  
Eccentric Orbits ◽  
Roche Limit ◽  
In Situ Formation ◽  
Synchronous Orbit

<p>The origin of the Martian moons, Phobos and Deimos, remains elusive. While the morphology and their cratered surfaces suggest an asteroidal origin, capture has been questioned because of potential dynamical difficulties in achieving the current near-circular, near-equatorial orbits. To circumvent this, in situ formation models have been proposed as alternatives. Yet, explaining the present location of the moons on opposite sides of the synchronous radius, their small sizes and apparent compositional differences with Mars has proved challenging. Here, we combine geophysical and tidal-evolution modelling of a Mars–satellite system to propose that Phobos and Deimos originated from disintegration of a common progenitor that was possibly formed in situ. We show that tidal dissipation within a Mars–satellite system, enhanced by the physical libration of the satellite, circularizes the post-disrupted eccentric orbits in <2.7 Gyr and makes Phobos descend to its present orbit from its point of origin close to or above the synchronous orbit. Our estimate for Phobos’s maximal tidal lifetime is considerably less than the age of Mars, indicating that it is unlikely to have originated alongside Mars. Deimos initially moved inwards, but never transcended the co-rotation radius because of insufficient eccentricity and therefore insufficient tidal dissipation. Whereas Deimos is very slowly receding from Mars, Phobos will continue to spiral towards and either impact with Mars or become tidally disrupted on reaching the Roche limit in <span class="stix">≲</span>39 Myr.</p>

scholarly journals Exploring formation scenarios for the exomoon candidate Kepler 1625b I

2020 ◽  
Vol 495 (4) ◽  
pp. 3763-3776 ◽  
Author(s):  
R A Moraes ◽  
E Vieira Neto
Keyword(s):  
Solar System ◽  
Satellite System ◽  
Minimum Amount ◽  
Tidal Evolution ◽  
Satellite Formation ◽  
Natural Satellite ◽  
In Situ Formation ◽  
Do So

ABSTRACT If confirmed, the Neptune-size exomoon candidate in the Kepler 1625 system will be the first natural satellite outside our Solar system. Its characteristics are nothing alike we know for a satellite. Kepler 1625b I is expected to be as massive as Neptune and to orbit at 40 planetary radii around a ten Jupiter mass planet. Because of its mass and wide orbit, this satellite was first thought to be captured instead of formed in situ. In this work, we investigated the possibility of an in situ formation of this exomoon candidate. To do so, we performed N-body simulations to reproduce the late phases of satellite formation and use a massive circumplanetary disc to explain the mass of this satellite. Our setups started soon after the gaseous nebula dissipation, when the satellite embryos are already formed. Also for selected exomoon systems, we take into account a post-formation tidal evolution. We found that in situ formation is viable to explain the origin of Kepler 1625b I, even when different values for the star–planet separation are considered. We show that for different star–planet separations the minimum amount of solids needed in the circumplanetary disc to form such a satellite varies, the wider is this separation more material is needed. In our simulations of satellite formation, many satellites were formed close to the planet, this scenario changed after the tidal evolution of the systems. We concluded that if the Kepler1625 b satellite system was formed in situ, tidal evolution was an important mechanism to sculpt its final architecture.

scholarly journals Co-accretion + Giant Impact Origin of the Uranus System: Post-impact Evolution

2022 ◽  
Vol 924 (1) ◽  
pp. 6
Author(s):  
Julien Salmon ◽  
Robin M. Canup
Keyword(s):  
Satellite System ◽  
Tidal Dissipation ◽  
Icy Moons ◽  
Giant Impact ◽  
Uranian Satellites ◽  
Post Impact ◽  
Debris Disk ◽  
Synchronous Orbit ◽  
Gas Accretion ◽  
Impact Origin

Abstract We investigate aspects of the co-accretion + giant impact scenario proposed by Morbidelli et al. (2012) for the origin of the Uranian satellites. In this model, a regular satellite system formed during gas accretion is impulsively destabilized by a Uranus-tipping impact, producing debris that ultimately re-orients to the planet’s new equatorial plane and re-accumulates into Uranus’ current large moons. We first investigate the nodal randomization of a disk of debris resulting from disruptive collisions between the hypothesized prior satellites. Consistent with Morbidelli et al., we find that an impact-generated interior c-disk with mass ≥10−2 Uranus masses is needed to cause sufficient nodal randomization to appropriately realign the outer debris disk. We then simulate the reaccumulation of the outer debris disk into satellites and find that disks with larger initial radii are needed to produce an outer debris disk that extends to Oberon’s distance, and that Uranus’ obliquity prior to the giant impact must have been substantial, ≥40°, if its original co-accreted satellite system was broadly similar in radial scale to those at Jupiter and Saturn today. Finally, we explore the subsequent evolution of a massive, water-dominated inner c-disk as it condenses, collisionally spreads, and spawns new moons beyond the Roche limit. We find that intense tidal dissipation in Uranus (i.e., ( Q / k 2 ) U ≤ 10 2 ) is needed to prevent large icy moons spawned from the inner disk from expanding beyond the synchronous orbit, where they would be long lived and inconsistent with the lack of massive inner moons at Uranus today. We conclude that while a co-accretion + giant impact is viable it requires rather specific conditions.

scholarly journals Formation of compact systems of super-Earths via dynamical instabilities and giant impacts

2019 ◽  
Vol 491 (4) ◽  
pp. 5595-5620 ◽  
Author(s):  
Sanson T S Poon ◽  
Richard P Nelson ◽  
Seth A Jacobson ◽  
Alessandro Morbidelli
Keyword(s):  
Initial Conditions ◽  
Post Processing ◽  
Significant Modification ◽  
Kepler Mission ◽  
Giant Impacts ◽  
Low Mass ◽  
In Situ Formation ◽  
Dynamical Instabilities ◽  
Gaseous Envelopes

ABSTRACT The NASA’s Kepler mission discovered ∼700 planets in multiplanet systems containing three or more transiting bodies, many of which are super-Earths and mini-Neptunes in compact configurations. Using N-body simulations, we examine the in situ, final stage assembly of multiplanet systems via the collisional accretion of protoplanets. Our initial conditions are constructed using a subset of the Kepler five-planet systems as templates. Two different prescriptions for treating planetary collisions are adopted. The simulations address numerous questions: Do the results depend on the accretion prescription?; do the resulting systems resemble the Kepler systems, and do they reproduce the observed distribution of planetary multiplicities when synthetically observed?; do collisions lead to significant modification of protoplanet compositions, or to stripping of gaseous envelopes?; do the eccentricity distributions agree with those inferred for the Kepler planets? We find that the accretion prescription is unimportant in determining the outcomes. The final planetary systems look broadly similar to the Kepler templates adopted, but the observed distributions of planetary multiplicities or eccentricities are not reproduced, because scattering does not excite the systems sufficiently. In addition, we find that ∼1 per cent of our final systems contain a co-orbital planet pair in horseshoe or tadpole orbits. Post-processing the collision outcomes suggests that they would not significantly change the ice fractions of initially ice-rich protoplanets, but significant stripping of gaseous envelopes appears likely. Hence, it may be difficult to reconcile the observation that many low-mass Kepler planets have H/He envelopes with an in situ formation scenario that involves giant impacts after dispersal of the gas disc.

scholarly journals Method for determining the thermal conductivity of in situ formation rock using drilling cuttings

AIP Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 065015
Author(s):  
Fu Yi ◽  
Xupeng Qi ◽  
Xuexin Zheng ◽  
Huize Yu ◽  
Wenming Bai ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
In Situ Formation

scholarly journals In situ formation of a carbon nanotube buckypaper for improving the interlaminar properties of carbon fiber composites

2021 ◽  
Vol 202 ◽  
pp. 109535
Author(s):  
Yadong Wu ◽  
Xiuyan Cheng ◽  
Shaoyun Chen ◽  
Bo Qu ◽  
Rui Wang ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Carbon Fiber ◽  
Fiber Composites ◽  
Carbon Fiber Composites ◽  
In Situ Formation

In Situ Formation of Ag Nanoparticles for Fiber Strain Sensors: Toward Textile-Based Wearable Applications

2021 ◽  
Author(s):  
Hwajoong Kim ◽  
Ammar Shaqeel ◽  
Solbi Han ◽  
Junseo Kang ◽  
Jieun Yun ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Strain Sensors ◽  
In Situ Formation

A novel and facile route to in-situ formation of composites with dual coupling interactions for considerable millimeter-wave absorption performance

2021 ◽  
Author(s):  
Chuyang Liu ◽  
Tao Jiang ◽  
Tian Gao ◽  
Guangxian Xia ◽  
Yufan Cao ◽  
...  
Keyword(s):  
Millimeter Wave ◽  
Exchange Coupling ◽  
Ferromagnetic Coupling ◽  
Soft Magnetic ◽  
Magnetic Exchange ◽  
Magnetic Exchange Coupling ◽  
Absorption Performance ◽  
In Situ Formation ◽  
Facile Route

It is well known that both hard/soft magnetic exchange-coupling and ferroelectric-ferromagnetic coupling could facilitate the microwave absorption behavior. Herein, we propose the BaZrxFe12-xO19/Fe3O4/BaZrO3 composites to integrate the advantages of the...

In-situ formation of LiF-rich composite interlayer for dendrite-free all-solid-state lithium batteries

2021 ◽  
Vol 411 ◽  
pp. 128534
Author(s):  
Jianli Wang ◽  
Zhao Zhang ◽  
Hangjun Ying ◽  
Gaorong Han ◽  
Wei-Qiang Han
Keyword(s):  
Solid State ◽  
Lithium Batteries ◽  
In Situ Formation
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