scholarly journals A pair of Jovian Trojans at the L4 Lagrange point

2020 ◽  
Vol 499 (3) ◽  
pp. 3630-3649
Author(s):  
Timothy R Holt ◽  
David Vokrouhlický ◽  
David Nesvorný ◽  
Miroslav Brož ◽  
Jonathan Horner
Keyword(s):  
Binary System ◽  
Single Object ◽  
Main Belt ◽  
Lagrange Point ◽  
Proper Elements ◽  
Numerical Integrations ◽  
Major Interest ◽  
Planetary Migration ◽  
Catastrophic Impact ◽  
Rule Out

ABSTRACT Asteroid pairs, two objects that are not gravitationally bound to one another, but share a common origin, have been discovered in the Main belt and Hungaria populations. Such pairs are of major interest, as the study of their evolution under a variety of dynamical influences can indicate the time since the pair was created. To date, no asteroid pairs have been found in the Jovian Trojans, despite the presence of several binaries and collisional families in the population. The search for pairs in the Jovian Trojan population is of particular interest, given the importance of the Trojans as tracers of planetary migration during the Solar system’s youth. Here we report a discovery of the first pair, (258656) 2002 ES76 and 2013 CC41, in the Jovian Trojans. The two objects are approximately the same size and are located very close to the L4 Lagrange point. Using numerical integrations, we find that the pair is at least 360 Myr old, though its age could be as high as several Gyrs. The existence of the (258656) 2002 ES76–2013 CC41 pair implies there could be many such pairs scattered through the Trojan population. Our preferred formation mechanism for the newly discovered pair is through the dissociation of an ancient binary system, triggered by a sub-catastrophic impact, but we can not rule out rotation fission of a single object driven by YORP torques. A by-product of our work is an up-to-date catalogue of Jovian Trojan proper elements, which we have made available for further studies.

scholarly journals The Dynamics of the Trojan Asteroids

1994 ◽  
Vol 160 ◽  
pp. 159-174
Author(s):  
Andrea Milani
Keyword(s):  
State Of The Art ◽  
Stability Boundary ◽  
Synthetic Method ◽  
Dynamical Structure ◽  
Main Belt ◽  
Trojan Asteroids ◽  
Proper Elements ◽  
Numerical Integrations ◽  
The Stability ◽  
The One

The state of the art in the dynamics of the Trojan asteroids has progressed rapidly, since it has been possible to perform numerical integrations of many orbits for millions of years. Accurate proper elements are now computed by the synthetic method, that is from the output of a numerical integration; their stability, at least for time spans of a few million years, is good. This has allowed identification of Trojan families with an automated procedure closely mimicking the one used in the main belt. Although the families identified in a reliable way are only four, the occurrence of significant collisional evolution, not unlike that of the main belt, can be confirmed. The dynamical structure of the Trojan cloud, including the location of the main secular resonances, can be deduced from the proper elements and frequencies by a simple fit. However, many problems are not solved: the origin of a significant percentage of chaotic orbits showing no indications of instability; the location of the stability boundary of the Trojan cloud; the origin of the high inclination of most Trojans. We also do not know if there are “Trojans” for some other planets beside Jupiter: only one Mars Trojan has been found.

scholarly journals Asteroid Proper Elements: The Big Picture

1994 ◽  
Vol 160 ◽  
pp. 143-158 ◽  
Author(s):  
Zoran Knežević ◽  
Andrea Milani
Keyword(s):  
Point Of View ◽  
Dynamical Structure ◽  
Main Belt ◽  
Secular Resonances ◽  
Mean Motion Resonances ◽  
Mean Motion ◽  
Proper Elements ◽  
Big Picture ◽  
Linear And Nonlinear ◽  
Asteroid Families

Four perturbation theories presently used to compute asteroid proper elements are reviewed, and their results are briefly discussed (Milani and Knežević, 1990, 1992, 1994, for low to moderate eccentricity/inclination main belt objects; Lemaitre and Morbidelli, 1994, for high e, I objects; Milani, 1993, for Trojans; Schubart, 1982, 1991 for Hildas). The most important recent improvements are described, in particular those pertaining to the upgrades of the previous analytic and semianalytic solutions. The dynamical structure of the asteroid main belt, as defined by the low order mean motion resonances and by linear and nonlinear secular resonances, is considered from the point of view of the effects of these resonances on the accuracy and/or reliability of the computation of proper elements and on the reliability of the identification of asteroid families.

Asteroid Proper Elements and the Dynamical Structure of the Asteroid Main Belt

Icarus ◽  
1994 ◽  
Vol 107 (2) ◽  
pp. 219-254 ◽  
Author(s):  
Andrea Milani ◽  
Zoran KnežEvić
Keyword(s):  
Dynamical Structure ◽  
Main Belt ◽  
Proper Elements

scholarly journals A Composite Catalogue of Asteroid Proper Elements

1994 ◽  
Vol 160 ◽  
pp. 467-470
Author(s):  
Andrea Milani ◽  
Edward Bowell ◽  
Zoran Knežević ◽  
Anne Lemaitre ◽  
Alessandro Morbidelli ◽  
...  
Keyword(s):  
Numerical Integration ◽  
State Of The Art ◽  
Public Domain ◽  
The State ◽  
Asteroid Belt ◽  
Synthetic Theory ◽  
Main Belt ◽  
The Public ◽  
Proper Elements

We have assembled the asteroid proper elements computed by different authors, using different methods, and for different regions of the asteroid belt. Asteroids on planet crossing orbits are not yet included. The use of very different algorithms is dictated by the dynamics of the different regions. For the asteroids of the main belt, having semimajor axes between 2.1 and 3.8 AU, and with proper eccentricity and sine of inclination less than 0.3, proper elements are computed by a fully analytical iterative theory developed by Milani and Knežević (1990,1992,1994; hereafter M&K). For high inclination and/or eccentricity main-belt asteroids, having 1.8 < a < 3.8 AU and either e or sin I larger than 0.24, proper elements are computed by a semianalytical theory developed by Lemaitre and Morbidelli (1994; hereafter L&M). For Trojans, proper elements are computed by a synthetic theory (that is, from the output of a numerical integration for a few Myr) by Milani (1993). For the Hilda asteroids in the 3: 2 resonance, proper elements have been computed by a synthetic theory by Schubart (1982, 1991). For a discussion of the state of the art in the computation of proper elements, see Knežević and Milani, this volume; for Trojans, see Milani, this volume; for some other cases (e.g. proper elements for resonant asteroids), see Froeschlé and Morbidelli, this volume. When and if new proper elements will be available for other asteroids, they will be added to the public domain file, together with updates and upgrades of the existing catalogues.

scholarly journals Spectroscopy of the Stellar Wind in the Cygnus X-1 System

10.14311/1332 ◽  
2011 ◽  
Vol 51 (1) ◽  
Author(s):  
I. Miškovičová ◽  
M. Hanke ◽  
J. Wilms ◽  
M. A. Nowak ◽  
K. Pottschmidt ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Binary System ◽  
Stellar Wind ◽  
Roche Lobe ◽  
High Mass ◽  
Lagrange Point ◽  
Companion Star ◽  
X Ray ◽  
Accretion Flow

The X-ray luminosity of black holes is produced through the accretion of material from their companion stars. Depending on the mass of the donor star, accretion of the material falling onto the black hole through the inner Lagrange point of the system or accretion by the strong stellar wind can occur. Cygnus X-1 is a high mass X-ray binary system, where the black hole is powered by accretion of the stellar wind of its supergiant companion star HDE226868. As the companion is close to filling its Roche lobe, the wind is not symmetric, but strongly focused towards the black hole. Chandra-HETGS observations allow for an investigation of this focused stellar wind, which is essential to understand the physics of the accretion flow. We compare observations at the distinct orbital phases of 0.0, 0.2, 0.5 and 0.75. These correspond to different lines of sight towards the source, allowing us to probe the structure and the dynamics of the wind.

scholarly journals A Uranian Trojan and the Frequency of Temporary Giant-Planet Co-Orbitals

Science ◽  
2013 ◽  
Vol 341 (6149) ◽  
pp. 994-997 ◽  
Author(s):  
Mike Alexandersen ◽  
Brett Gladman ◽  
Sarah Greenstreet ◽  
J. J. Kavelaars ◽  
Jean-Marc Petit ◽  
...  
Keyword(s):  
Giant Planet ◽  
Minor Planet ◽  
International Astronomical Union ◽  
Lagrange Point ◽  
Lagrangian Points ◽  
Numerical Integrations ◽  
International Astronomical ◽  
Centre Database

Trojan objects share a planet’s orbit, never straying far from the triangular Lagrangian points, 60° ahead of (L4) or behind (L5) the planet. We report the detection of a Uranian Trojan; in our numerical integrations, 2011 QF99 oscillates around the Uranian L4 Lagrange point for >70,000 years and remains co-orbital for ∼1 million years before becoming a Centaur. We constructed a Centaur model, supplied from the transneptunian region, to estimate temporary co-orbital capture frequency and duration (to a factor of 2 accuracy), finding that at any time 0.4 and 2.8% of the population will be Uranian and Neptunian co-orbitals, respectively. The co-orbital fraction (∼2.4%) among Centaurs in the International Astronomical Union Minor Planet Centre database is thus as expected under transneptunian supply.

scholarly journals Secular evolution of asteroid families: the role of Ceres

2015 ◽  
Vol 10 (S318) ◽  
pp. 46-54 ◽  
Author(s):  
Bojan Novaković ◽  
Georgios Tsirvoulis ◽  
Stefano Marò ◽  
Vladimir Đošović ◽  
Clara Maurel
Keyword(s):  
Numerical Simulations ◽  
Main Belt ◽  
Secular Resonance ◽  
Secular Evolution ◽  
Secular Dynamics ◽  
Proper Elements ◽  
Post Impact ◽  
Actual Shape ◽  
Asteroid Families

AbstractWe consider the role of the dwarf planet Ceres on the secular dynamics of the asteroid main belt. Specifically, we examine the post impact evolution of asteroid families due to the interaction of their members with the linear nodal secular resonance with Ceres. First, we find the location of this resonance and identify which asteroid families are crossed by its path. Next, we summarize our results for three asteroid families, namely (1726) Hoffmeister, (1128) Astrid and (1521) Seinajoki which have irregular distributions of their members in the proper elements space, indicative of the effect of the resonance. We confirm this by performing a set of numerical simulations, showcasing that the perturbing action of Ceres through its linear nodal secular resonance is essential to reproduce the actual shape of the families.

scholarly journals The formation of habitable planets in the four-planet system HD 141399

2019 ◽  
Vol 488 (4) ◽  
pp. 5604-5614 ◽  
Author(s):  
R Dvorak ◽  
B Loibnegger ◽  
L Y Zhou ◽  
L Zhou
Keyword(s):  
Initial Conditions ◽  
Gravitational Interaction ◽  
Equations Of Motion ◽  
Terrestrial Planets ◽  
Habitable Zone ◽  
Main Belt ◽  
Small Bodies ◽  
Mean Motion Resonances ◽  
Numerical Integrations ◽  
Structure Analogue

ABSTRACT The presented work investigates the possible formation of terrestrial planets in the habitable zone (HZ) of the exoplanetary system HD 141399. In this system, the HZ is located approximately between the planets c (a  = 0.7 au) and d (a  = 2.1 au). Extensive numerical integrations of the equations of motion in the pure Newtonian framework of small bodies with different initial conditions in the HZ are performed. Our investigations included several steps starting with 500 massless bodies distributed between planets c and d in order to model the development of the disc of small bodies. It turns out that after some 106 yr, a belt-like structure analogue to the main belt inside Jupiter in our Solar system appears. We then proceed with giving the small bodies masses (∼ Moon mass) and take into account the gravitational interaction between these planetesimal-like objects. The growing of the objects – with certain percentage of water – due to collisions is computed in order to look for the formation of terrestrial planets. We observe that planets form in regions connected to mean motion resonances (MMR). So far there is no observational evidence of terrestrial planets in the system of HD 141399 but from our results we can conclude that the formation of terrestrial planets – even with an appropriate amount of water necessary for being habitable – in the HZ would have been possible.

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