scholarly journals Enrichment of the HR 8799 planets by minor bodies and dust

2020 ◽  
Vol 638 ◽  
pp. A50
Author(s):  
K. Frantseva ◽  
M. Mueller ◽  
P. Pokorný ◽  
F. F. S. van der Tak ◽  
I. L. ten Kate
Keyword(s):  
Total Mass ◽  
Kuiper Belt ◽  
Giant Planets ◽  
Asteroid Belt ◽  
Dynamical Structure ◽  
Mean Motion Resonances ◽  
Exoplanetary Systems ◽  
Test Particles ◽  
Main Asteroid Belt ◽  
The Impact

Context. In the Solar System, minor bodies and dust deliver various materials to planetary surfaces. Several exoplanetary systems are known to host inner and outer belts, analogues of the main asteroid belt and the Kuiper belt, respectively. Aims. We study the possibility that exominor bodies and exodust deliver volatiles and refractories to the exoplanets in the well-characterised system HR 8799. Methods. We performed N-body simulations to study the impact rates of minor bodies in the system HR 8799. The model consists of the host star, four giant planets (HR 8799 e, d, c, and b), 650 000 test particles representing the inner belt, and 1 450 000 test particles representing the outer belt. Moreover we modelled dust populations that originate from both belts. Results. Within a million years, the two belts evolve towards the expected dynamical structure (also derived in other works), where mean-motion resonances with the planets carve the analogues of Kirkwood gaps. We find that, after this point, the planets suffer impacts by objects from the inner and outer belt at rates that are essentially constant with time, while dust populations do not contribute significantly to the delivery process. We convert the impact rates to volatile and refractory delivery rates using our best estimates of the total mass contained in the belts and their volatile and refractory content. Over their lifetime, the four giant planets receive between 10−4 and 10−3 M⊕ of material from both belts. Conclusions. The total amount of delivered volatiles and refractories, 5 × 10−3 M⊕, is small compared to the total mass of the planets, 11 × 103 M⊕. However, if the planets were formed to be volatile-rich, their exogenous enrichment in refractory material may well be significant and observable, for example with JWST-MIRI. If terrestrial planets exist within the snow line of the system, volatile delivery would be an important astrobiological mechanism and may be observable as atmospheric trace gases.

scholarly journals Enrichment of the HR 8799 planets by minor bodies and dust

2020 ◽  
Author(s):  
Kateryna Frantseva ◽  
Michael Mueller ◽  
Petr Pokorný ◽  
Floris F. S. van der Tak ◽  
Inge Loes ten Kate
Keyword(s):  
Solar System ◽  
Total Mass ◽  
Kuiper Belt ◽  
Giant Planets ◽  
Asteroid Belt ◽  
Refractory Materials ◽  
Exoplanetary Systems ◽  
Main Asteroid Belt ◽  
The Impact ◽  
Shed Light

<p>Are minor bodies and dust delivering volatile and/or refractory materials in exoplanetary systems?<span class="Apple-converted-space"> </span></p> <p>Around ~20% of the nearest stars are found to host analogues of the main asteroid belt and the Kuiper belt. Our aim is to study the possibility of material delivery through minor bodies and dust to the planetary surfaces. To shed light on these delivery processes we extrapolate our Solar System scenarios to the exoplanetary system HR 8799. The system is known to host four giant planets and two belts of minor bodies.</p> <p>We performed a set of N-body simulations to study the impact rates of minor bodies and dust on the HR 8799 planets. We find that the planets suffer impacts by objects from the inner and outer belt. We convert these to volatile and refractory delivery rates using our best estimates of the total mass contained in the belts and their volatile/refractory content. Over their lifetime, the four giant planets receive between 10<sup>-4</sup> and 10<sup>-3 </sup>M<sub>Earth</sub> of material from both belts. This delivery leads to volatile and refractory enrichment of the planets that may be observable. Since the four giants HR 8799 e, d, c, b are located beyond the snow line (and presumably formed there), we expect them to be born volatile-rich. Therefore any future detection of refractories might imply delivery through impacts.</p>

scholarly journals No evidence for interstellar planetesimals trapped in the Solar system

2020 ◽  
Vol 497 (1) ◽  
pp. L46-L49 ◽  
Author(s):  
A Morbidelli ◽  
K Batygin ◽  
R Brasser ◽  
S N Raymond
Keyword(s):  
Solar System ◽  
Oort Cloud ◽  
Giant Planets ◽  
Asteroid Belt ◽  
Interstellar Space ◽  
Fast Decay ◽  
Early Solar System ◽  
The Past ◽  
Solar System Bodies ◽  
Main Asteroid Belt

ABSTRACT In two recent papers published in MNRAS, Namouni and Morais claimed evidence for the interstellar origin of some small Solar system bodies, including: (i) objects in retrograde co-orbital motion with the giant planets and (ii) the highly inclined Centaurs. Here, we discuss the flaws of those papers that invalidate the authors’ conclusions. Numerical simulations backwards in time are not representative of the past evolution of real bodies. Instead, these simulations are only useful as a means to quantify the short dynamical lifetime of the considered bodies and the fast decay of their population. In light of this fast decay, if the observed bodies were the survivors of populations of objects captured from interstellar space in the early Solar system, these populations should have been implausibly large (e.g. about 10 times the current main asteroid belt population for the retrograde co-orbital of Jupiter). More likely, the observed objects are just transient members of a population that is maintained in quasi-steady state by a continuous flux of objects from some parent reservoir in the distant Solar system. We identify in the Halley-type comets and the Oort cloud the most likely sources of retrograde co-orbitals and highly inclined Centaurs.

scholarly journals Masses of asteroids and total mass of the main asteroid belt

2015 ◽  
Vol 10 (S318) ◽  
pp. 212-217
Author(s):  
E. V. Pitjeva ◽  
N. P. Pitjev
Keyword(s):  
Total Mass ◽  
Radar Data ◽  
Asteroid Belt ◽  
Two Dimensional ◽  
Binary Asteroids ◽  
One Dimensional ◽  
Main Asteroid Belt ◽  
The Individual ◽  
The Masses ◽  
Academy Of Sciences

AbstractAn estimation of the mass of the main asteroid belt was made on the basis of the new version of EPM2014 ephemerides of the Institute of Applied Astronomy of Russian Academy of Sciences using about 800000 positional observations of planets and spacecraft. We obtained the individual estimations of masses of large asteroids from radar data, as well as estimates of the masses of asteroids by using known diameters and estimated average densities for the three taxonomic types (C, S, M), and used the known mass values of binary asteroids and asteroids to which spacecraft approached. A two-dimensional homogeneous annulus with dimensions corresponding observed width of the main asteroid belt (2.06 au and 3.27 au) was used instead of a previous massive one-dimensional ring for modeling total perturbations from small asteroids. The obtained value of the total mass of the main asteroid belt is (12.25 ± 0.19)10−10M⊙.

scholarly journals Planetary Trojans – the main source of short period comets?

2010 ◽  
Vol 9 (4) ◽  
pp. 227-234 ◽  
Author(s):  
J. Horner ◽  
P. S. Lykawka
Keyword(s):  
Solar System ◽  
Short Review ◽  
Oort Cloud ◽  
Asteroid Belt ◽  
Exoplanetary Systems ◽  
Short Period ◽  
Proximate Source ◽  
Different Origins ◽  
Near Earth Asteroids ◽  
The Impact

AbstractOne of the key considerations when assessing the potential habitability of telluric worlds will be that of the impact regime experienced by the planet. In this work, we present a short review of our understanding of the impact regime experienced by the terrestrial planets within our own Solar system, describing the three populations of potentially hazardous objects which move on orbits that take them through the inner Solar system. Of these populations, the origins of two (the Near-Earth Asteroids and the Long-Period Comets) are well understood, with members originating in the Asteroid belt and Oort cloud, respectively. By contrast, the source of the third population, the Short-Period Comets, is still under debate. The proximate source of these objects is the Centaurs, a population of dynamically unstable objects that pass perihelion (closest approach to the Sun) between the orbits of Jupiter and Neptune. However, a variety of different origins have been suggested for the Centaur population. Here, we present evidence that at least a significant fraction of the Centaur population can be sourced from the planetary Trojan clouds, stable reservoirs of objects moving in 1:1 mean-motion resonance with the giant planets (primarily Jupiter and Neptune). Focussing on simulations of the Neptunian Trojan population, we show that an ongoing flux of objects should be leaving that region to move on orbits within the Centaur population. With conservative estimates of the flux from the Neptunian Trojan clouds, we show that their contribution to that population could be of order ~3%, while more realistic estimates suggest that the Neptune Trojans could even be the main source of fresh Centaurs. We suggest that further observational work is needed to constrain the contribution made by the Neptune Trojans to the ongoing flux of material to the inner Solar system, and believe that future studies of the habitability of exoplanetary systems should take care not to neglect the contribution of resonant objects (such as planetary Trojans) to the impact flux that could be experienced by potentially habitable worlds.

scholarly journals Habitable zones for Earth-mass planets in multiple planetary systems

2007 ◽  
Vol 3 (S249) ◽  
pp. 499-502
Author(s):  
Jianghui JI ◽  
Lin LIU ◽  
Hiroshi KINOSHITA ◽  
Guangyu LI
Keyword(s):  
Planetary Systems ◽  
Terrestrial Planet ◽  
Asteroid Belt ◽  
Terrestrial Planets ◽  
Dynamical Structure ◽  
Mean Motion Resonances ◽  
Outer Planets ◽  
Habitable Zones ◽  
Candidate Regions ◽  
Orbital Resonances

AbstractWe perform numerical simulations to study the Habitable zones (HZs) and dynamical structure for Earth-mass planets in multiple planetary systems. For example, in the HD 69830 system, we extensively explore the planetary configuration of three Neptune-mass companions with one massive terrestrial planet residing in 0.07 AU ≤ a ≤ 1.20 AU, to examine the asteroid structure in this system. We underline that there are stable zones of at least 105 yr for low-mass terrestrial planets locating between 0.3 and 0.5 AU, and 0.8 and 1.2 AU with final eccentricities of e < 0.20. Moreover, we also find that the accumulation or depletion of the asteroid belt are also shaped by orbital resonances of the outer planets, for example, the asteroidal gaps at 2:1 and 3:2 mean motion resonances (MMRs) with Planet C, and 5:2 and 1:2 MMRs with Planet D. In a dynamical sense, the proper candidate regions for the existence of the potential terrestrial planets or HZs are 0.35 AU < a < 0.50 AU, and 0.80 AU < a < 1.00 AU for relatively low eccentricities, which makes sense to have the possible asteroidal structure in this system.

scholarly journals Higher Order and Iterative Theories to Compute Asteroid Mean Elements

1999 ◽  
Vol 172 ◽  
pp. 359-360 ◽  
Author(s):  
Z. Knežević ◽  
A. Milani
Keyword(s):  
Asteroid Belt ◽  
Dynamical Structure ◽  
Orbital Elements ◽  
Mean Motion Resonances ◽  
First Order ◽  
Mean Motion ◽  
Long Time ◽  
The Mean ◽  
Mean Elements ◽  
Asteroid Families

Mean orbital elements are obtained from their instantaneous, osculating counterparts by removal of the short periodic perturbations. They can be computed by means of different theories, analytical or numerical, depending on the problem and accuracy required. The most advanced contemporary analytical theory (Knežević 1988) accounts only for the perturbing effects due to Jupiter and Saturn, to the first order in their masses and to degree four in eccentricity and inclination. Nevertheless, the mean elements obtained by means of this theory are of satisfactory accuracy for majority of the asteroids in the main belt (Knežević et al. 1988), for the purpose of producing large catalogues of mean and proper elements, to identify asteroid families, to assess their age, to study the dynamical structure of the asteroid belt and chaotic phenomena of diffusion over very long time spans. In the vicinity of the main mean motion resonances, however, especially 2:1 mean motion resonance with Jupiter, these mean elements are of somewhat degraded accuracy.

scholarly journals The fate of planetesimal discs in young open clusters: implications for 1I/’Oumuamua, the Kuiper belt, the Oort cloud, and more

2019 ◽  
Vol 490 (1) ◽  
pp. 21-36 ◽  
Author(s):  
T O Hands ◽  
W Dehnen ◽  
A Gration ◽  
J Stadel ◽  
B Moore
Keyword(s):  
Solar System ◽  
Graphics Processing Units ◽  
Open Cluster ◽  
Kuiper Belt ◽  
Large Population ◽  
Oort Cloud ◽  
Open Clusters ◽  
Cluster Evolution ◽  
Exoplanetary Systems ◽  
Test Particles

ABSTRACT We perform N-body simulations of the early phases of open cluster evolution including a large population of planetesimals, initially arranged in Kuiper-belt like discs around each star. Using a new, fourth-order, and time-reversible N-body code on Graphics Processing Units (GPUs), we evolve the whole system under the stellar gravity, i.e. treating planetesimals as test particles, and consider two types of initial cluster models, similar to IC348 and the Hyades, respectively. In both cases, planetesimals can be dynamically excited, transferred between stars, or liberated to become free-floating (such as A/2017 U1 or ’Oumuamua) during the early cluster evolution. We find that planetesimals captured from another star are not necessarily dynamically distinct from those native to a star. After an encounter, both native and captured planetesimals can exhibit aligned periastrons, qualitatively similar to that seen in the Solar system and commonly thought to be the signature of Planet 9. We discuss the implications of our results for both our Solar system and exoplanetary systems.

scholarly journals Resonant Gaps in the Scattered Cometary Population of the Trans-Neptunian Region

2002 ◽  
Vol 12 ◽  
pp. 251-252
Author(s):  
Tanya Taidakova ◽  
Leonid M. Ozernoy ◽  
Nick N. Gorkavyi
Keyword(s):  
Numerical Simulations ◽  
Kuiper Belt ◽  
Giant Planets ◽  
Kuiper Belt Objects ◽  
Mean Motion Resonances ◽  
Mean Motion ◽  
Scattered Population

AbstractOur numerical simulations of the Edgeworth-Kuiper Belt objects gravitationally scattered by the four giant planets accounting for mean motion resonances reveal numerous resonant gaps in the distribution of the scattered population.

scholarly journals Origin of the dusty disks around white dwarfs

2007 ◽  
Vol 3 (S249) ◽  
pp. 381-384
Author(s):  
R. B. Dong ◽  
Y. Wang ◽  
D. N. C. Lin ◽  
X. W. Liu
Keyword(s):  
Total Mass ◽  
Main Sequence ◽  
Dynamical Evolution ◽  
Central Star ◽  
Orbital Evolution ◽  
Giant Planets ◽  
Mean Motion Resonances ◽  
Host Stars ◽  
Dusty Disks ◽  
Dust Ring

AbstractSome circumstantial evidence for residual planetesimals is constructed based on the recent discovery of a dusty ring around a young white dwarf at the center of the Helix nebula (Suet al. 2007). This ring extends between about 35 and 150 AU from the nebula center, and have a total mass of about 0.13M⊕. In this paper we propose that this ring is the by-product of planets and planetesimals' orbital evolution during the epoch when the central star rapidly lost most of its mass. We examine the dynamical evolution of planetary systems similar to the solar system (i.e. with gas giant planets and residual planetesimals) as their host stars evolve off the main sequence. During the process, some planetesimals will be captured by the gas giants into mean motion resonances and their mutual collisions will form a dust ring similar to that observed at the center of the Helix nebula.

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