scholarly journals Ring dynamics around an oblate body with an inclined satellite: the case of Haumea

2020 ◽  
Vol 643 ◽  
pp. A67
Author(s):  
Francesco Marzari
Keyword(s):  
Equatorial Plane ◽  
Protective Factor ◽  
Central Body ◽  
Orbital Plane ◽  
Major Axis ◽  
The Body ◽  
Triaxial Ellipsoid ◽  
Semi Major Axis ◽  
Short Timescale ◽  
The Impact

Context. The recent discovery of rings and massive satellites around minor bodies and dwarf planets suggests that they may often coexist, as for example around Haumea. Aims. A ring perturbed by an oblate central body and by an inclined satellite may disperse on a short timescale. The conditions under which a ring may survive are explored both analytically and numerically. Methods. The trajectories of ring particles are integrated under the influence of the gravitational field of a triaxial ellipsoid and (a) massive satellite(s), including the effects of collisions. Results. A ring initially formed in the equatorial plane of the central body will be disrupted if the satellite has an inclination in the Kozai–Lidov regime (39.2° < i < 144.8). For lower inclinations, the ring may relax to the satellite orbital plane thanks to an intense collisional damping. On the other hand, a significant J2 term easily suppresses the perturbations of an inclined satellite within a critical semi-major axis, even in the case of Kozai–Lidov cycles. However, if the ring is initially inclined with respect to the equatorial plane, the same J2 perturbations are not a protective factor but instead disrupt the ring on a short timescale. The ring found around Haumea is stable despite the rise in the impact velocities that is due to the asymmetric shape of the body and the presence of a 3:1 resonance with the rotation of the central body. Conclusions. A ring close to an oblate central body should be searched for in the proximity of the equatorial plane, where the J2 perturbations protect it against the perturbations of an external inclined satellites. In an inclined configuration, the J2 term is itself disruptive.

scholarly journals Influence of non-gravitational effects on the Centaur upper stage of the Surveyor 2 spacecraft

2021 ◽  
Vol 2103 (1) ◽  
pp. 012029
Author(s):  
A A Martyusheva ◽  
A V Devyatkin
Keyword(s):  
Solar Radiation Pressure ◽  
Close Approach ◽  
Major Axis ◽  
Semi Major Axis ◽  
Maximum Displacement ◽  
Gravitational Effects ◽  
Yarkovsky Effect ◽  
Upper Stage ◽  
The Impact ◽  
Heliocentric Orbit

Abstract A small near-Earth asteroid, discovered by the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) on September 17, 2020, turned out to be a part of the Centaur upper stage of the Surveyor 2 spacecraft launched by NASA on September 20, 1966 and subsequently crashed. This object had moved in a heliocentric orbit until it was under the influence of Earth’s gravitational field. As a result, a close approach to the Earth took place at a distance of about 50000 km on December 1, 2020. Despite the fact that the Centaur escaped back into a new orbit around the Sun in March 2021, it is of special interest for research, in particular, to consider the impact of non-gravitational effects on its orbital characteristics. Thus, it was calculated that the maximum displacement of the object trajectory due to the influence of solar radiation pressure over 15 years (the next close approach will take place in 2036) can be about 10.3-13.5 km, depending on the albedo. Estimations of the Yarkovsky effect showed that the magnitude of the expected change in the semi-major axis of Centaur’s orbit is from -8.1 • 10−13 to 1.6 10−13, depending on the angle of its rotation.

scholarly journals ORBITAL EFFECTS OF A TIME-DEPENDENT PIONEER-LIKE ANOMALOUS ACCELERATION

2012 ◽  
Vol 27 (12) ◽  
pp. 1250071 ◽  
Author(s):  
L. IORIO
Keyword(s):  
Major Axis ◽  
Time Dependent ◽  
Semi Major Axis ◽  
Orbital Parameters ◽  
Estimated Parameters ◽  
Secular Variations ◽  
Dependent Component ◽  
Orbital Revolution ◽  
Anomalous Acceleration ◽  
The Impact

We work out the impact that the recently determined time-dependent component of the Pioneer Anomaly (PA), if interpreted as an additional exotic acceleration of gravitational origin with respect to the well-known PA-like constant one, may have on the orbital motions of some planets of the solar system. By assuming that it points towards the Sun, it turns out that both the semi-major axis a and the eccentricity e of the orbit of a test particle would experience secular variations. For Saturn and Uranus, for which modern data records cover at least one full orbital revolution, such predicted anomalies are up to 2–3 orders of magnitude larger than the present-day accuracies in empirical determinations of their orbital parameters from the usual orbit determination procedures in which the PA was not modeled. Given the predicted huge sizes of such hypothetical signatures, it is unlikely that their absence from the presently available processed data can be attributable to an "absorption" for them in the estimated parameters caused by the fact that they were not explicitly modeled. The magnitude of a constant PA-type acceleration at 9.5 au cannot be larger than 9×10-15 m s-2 according to the latest observational results for the perihelion precession of Saturn.

Effect of an oblate rotating atmosphere on the orientation of a satellite orbit

1961 ◽  
Vol 261 (1305) ◽  
pp. 246-258 ◽  
Keyword(s):  
Orbital Plane ◽  
Satellite Orbit ◽  
Major Axis ◽  
Earth Satellite ◽  
Semi Major Axis ◽  
Orbital Inclination ◽  
Small Eccentricity ◽  
Earth Satellite Orbit ◽  
The Right ◽  
Right Ascension

For an earth satellite orbit of small eccentricity ( e < 0·2) formulae are derived for the changes per revolution produced by the atmosphere in the argument of perigee, in the right ascension of the ascending node, and in the orbital inclination. These changes are then expressed in terms of the change in length of the semi-major axis, and numerical values are obtained for satellite 1957 β . It is found that the rotation of the major axis in the orbital plane due to the atmosphere is significant, being most important for inclinations between 60 and 70°. The total rotation, due both to the gravitational potential and to the atmosphere, agrees reasonably well with the observed values. The oblateness of the atmosphere is found to have only a small effect on the changes in the orbital inclination and the right ascension of the ascending node.

scholarly journals The Impact of Transiting Planet Science on the Next Generation of Direct-Imaging Planet Searches

2008 ◽  
Vol 4 (S253) ◽  
pp. 556-559
Author(s):  
Joseph C. Carson
Keyword(s):  
A Priori ◽  
Major Axis ◽  
Next Generation ◽  
A Priori Information ◽  
Direct Imaging ◽  
Semi Major Axis ◽  
Absorption Bands ◽  
Imaging Results ◽  
Priori Information ◽  
The Impact

AbstractWithin the next five years, a number of direct-imaging planet search instruments, like the VLT SPHERE instrument, will be coming online. To successfully carry out their programs, these instruments will rely heavily on a-priori information on planet composition, atmosphere, and evolution. Transiting planet surveys, while covering a different semi-major axis regime, have the potential to provide critical foundations for these next-generation surveys. For example, improved information on planetary evolutionary tracks may significantly impact the insights that can be drawn from direct-imaging statistical data. Other high-impact results from transiting planet science include information on mass-to-radius relationships as well as atmospheric absorption bands. The marriage of transiting planet and direct-imaging results may eventually give us the first complete picture of planet migration, multiplicity, and general evolution.

scholarly journals Impact of the Atmospheric Drag on Starlette, Stella, Ajisai, and Lares Orbits

2015 ◽  
Vol 50 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Sośnica Krzysztof
Keyword(s):  
Major Axis ◽  
Radial Component ◽  
Satellite Orbits ◽  
Atmospheric Drag ◽  
Semi Major Axis ◽  
Station Coordinates ◽  
Earth Rotation Parameters ◽  
Out Of Plane ◽  
Along Track ◽  
The Impact

Abstract The high-quality satellite orbits of geodetic satellites, which are determined using Satellite Laser Ranging (SLR) observations, play a crucial role in providing, e.g., low-degree coefficients of the Earth's gravity field including geocenter coordinates, Earth rotation parameters, as well as the SLR station coordinates. The appropriate modeling of non-gravitational forces is essential for the orbit determination of artificial Earth satellites. The atmospheric drag is a dominating perturbing force for satellites at low altitudes up to about 700-1000 km. This article addresses the impact of the atmospheric drag on mean semi-major axes and orbital eccentricities of geodetic spherical satellites: Starlette, Stella, AJISAI, and LARES. Atmospheric drag causes the semi-major axis decays amounting to about ▲a = -1.2, -.12, -.14, and -.30 m/year for LARES, AJISAI, Starlette, and Stella, respectively. The density of the upper atmosphere strongly depends on the solar and geomagnetic activity. The atmospheric drag affects the along-track orbit component to the largest extent, and the out-of-plane to a small extent, whereas the radial component is almost unaffected by the atmospheric drag.

Revisiting astrometric parameters of quasars in Gaia-CRF2

2020 ◽  
Vol 635 ◽  
pp. A113
Author(s):  
C.-Y. Ding ◽  
Z. Zhu ◽  
J.-C. Liu ◽  
N. Liu
Keyword(s):  
Correlation Coefficients ◽  
Major Axis ◽  
Unit Weight ◽  
Asymmetric Distribution ◽  
Proper Motions ◽  
Semi Major Axis ◽  
Solution Quality ◽  
Dimensional Error ◽  
Mean Values ◽  
The Impact

Aims. In order to check the astrometric solution quality, dependences of parallaxes and proper motions on precision, reliability, and consistency of sample solutions are studied for the quasars in the celestial reference frame of the second release of Gaia data (Gaia-CRF2). Methods. Astrometric statistics (the number of visibility periods, the semi-major axis of the astrometric five-dimensional error ellipse σ5d,  max, the unit weight error u, the correlation coefficients ρμα*,  ϖ and ρμδ, ϖ) were selected to serve as indicators of the solution qualities of quasars. The dependences of the astrometric parameters, parallaxes and proper motions, on these indicators are evaluated. We also investigated mean values of astrometric statistics in equal-area spherical cells to study the impact of the scanning law. Results. The astrometric parameters of quasars with fewer than 9 or more than 18 visibility periods show a departure from the global average. Moreover, the mean values of astrometric parameters of the most precise sources deviate from the others. Astrometric parameters are stable for those quasars fitting the five-parameter model well. The correlation coefficients, ρμα*, ϖ and ρμδ, ϖ obtained from the astrometric solutions show a generally ideal distribution for the full sample. Spherical-cell mean values of these correlation coefficients are found to have a centrally asymmetric distribution. Distributions of two correlation coefficients are found to correlate with the number of visibility periods. The quasars with visibility periods in the domain [13, 16], with ρμα*, ϖ and ρμδ, ϖ generally well-distributed have more reliable astrometric parameters. Magnitudes and colours are found to have little influence on the irregular patterns of the correlation coefficients.

scholarly journals A dynamical study of the Gefion asteroid family

2019 ◽  
Vol 622 ◽  
pp. A39 ◽  
Author(s):  
S. Aljbaae ◽  
J. Souchay ◽  
A. F. B. A. Prado ◽  
T. G. G. Chanut
Keyword(s):  
Target Function ◽  
Orbital Plane ◽  
Major Axis ◽  
Symplectic Integrators ◽  
Ejection Velocity ◽  
Semi Major Axis ◽  
Dynamical Study ◽  
Mean Motion Resonances ◽  
Yorp Effect ◽  
The Right

The Gefion asteroid family is a group of S-type asteroids located between the 8J:-3A and 5J:-2A mean-motion resonances. The 5J:-2A resonance seems to be responsible for the absence of the right side of the V-shape of this family. We aim in this work to present a detailed study on the Gefion family, motivated by the incompatibility found in previous family age estimations and the fact that this family could be seen as one of the most probable sources of L-chondrite meteorites. After eliminating all possible taxonomical and dynamical interlopers, we use a Monte Carlo method to analyze the semi-major axis evolution of several fictitious families under the influence of the Yarkovsky and Yarkovsky-O’Keefe-Radzievsky-Paddack (YORP) effects. We also perform simulations using symplectic integrators to account for the Yarkovsky effect (diurnal and seasonal versions) and the stochastic YORP effect. We make use of the distribution of the component of the ejection velocity field (vW) perpendicular to the orbital plane and the time dependence of the asymmetry of the distribution of the target function of a fictitious family generated with ejection velocity parameter 20+55−15 m s−1 to obtain an age estimate of 1030+19−67 Myr. We find that 6.5% of asteroids from the Gefion family can reach orbits similar to particles in the current near-Earth objects space; 73% of them are among the Amors asteroids, and the remaining ones are among the Apollos. We only found 0.5% from the Gefion family reaching the Mars-crossing space.

scholarly journals Escape Velocities from Unstable Triple Stars

1996 ◽  
Vol 169 ◽  
pp. 527-528
Author(s):  
J. Anosova ◽  
K. Tanikawa ◽  
J. Colin ◽  
L. Kiseleva ◽  
P. Eggleton
Keyword(s):  
Initial Conditions ◽  
Three Dimensional ◽  
Dynamical Evolution ◽  
Major Axis ◽  
Universal Constant ◽  
The Body ◽  
Close Binary ◽  
Semi Major Axis ◽  
System Of Units ◽  
Binary Orbit

In order to investigate a possible origin for stars with high peculiar velocities in the thick disc of our Galaxy, the dynamical evolution of 16 000 three-dimensional triple systems which consist of a binary with equal or comparable masses of componentsM1andM2and a low-mass third bodyM3is considered. We examine an extensive range of initial conditions with positions of the bodyM3randomly distributed around and inside the binary orbit.M3was given the initial radial velocityV0with respect to the center of inertia of the binary. The following dynamical system of units is used in this work: the unit of distance is the semi-major axis of the binary orbit, the unit of time is the period of the binary; the universal constant of gravity is unity. In these units the total mass of the close binary is 4π2.

scholarly journals Connecting planet formation and astrochemistry

2020 ◽  
Vol 642 ◽  
pp. A229 ◽  
Author(s):  
Alex J. Cridland ◽  
Ewine F. van Dishoeck ◽  
Matthew Alessi ◽  
Ralph E. Pudritz
Keyword(s):  
Chemical Composition ◽  
Planet Formation ◽  
Chemical Properties ◽  
Major Axis ◽  
Recent Analysis ◽  
Element Abundance ◽  
Semi Major Axis ◽  
Hot Jupiters ◽  
Erosion Models ◽  
The Impact

The chemical composition of planetary atmospheres has long been thought to store information regarding where and when a planet accretes its material. Predicting this chemical composition theoretically is a crucial step in linking observational studies to the underlying physics that govern planet formation. As a follow-up to an earlier study of ours on hot Jupiters, we present a population of warm Jupiters (semi-major axis between 0.5 and 4 AU) extracted from the same planetesimal formation population synthesis model as used in that previous work. We compute the astrochemical evolution of the proto-planetary disks included in this population to predict the carbon-to-oxygen (C/O) and nitrogen-to-oxygen (N/O) ratio evolution of the disk gas, ice, and refractory sources, the accretion of which greatly impacts the resulting C/Os and N/Os in the atmosphere of giant planets. We confirm that the main sequence (between accreted solid mass and the atmospheric C/O) we found previously is largely reproduced by the presented population of synthetic warm Jupiters. As a result, the majority of the population falls along the empirically derived mass-metallicity relation when the natal disk has solar or lower metallicity. Planets forming from disks with high metallicity ([Fe/H] > 0.1) results in more scatter in chemical properties, which could explain some of the scatter found in the mass-metallicity relation. Combining predicted C/Os and N/Os shows that Jupiter does not fall among our population of synthetic planets, suggesting that it likely did not form in the inner 5 AU of the Solar System before proceeding into a Grand Tack. This result is consistent with a recent analysis of the chemical composition of Jupiter’s atmosphere, which suggests that it accreted most of its heavy element abundance farther than tens of AU away from the Sun. Finally, we explore the impact of different carbon refractory erosion models, including the location of the carbon erosion front. Shifting the erosion front has a major impact on the resulting C/Os of Jupiter- and Neptune-like planets, but warm Saturns see a smaller shift in C/Os since their carbon and oxygen abundances are equally impacted by gas and refractory accretion.

scholarly journals Maneuvering Hydrodynamics of Ellipsoidal Forms

1979 ◽  
Vol 23 (01) ◽  
pp. 66-75
Author(s):  
Touvia Miloh
Keyword(s):  
Closed Form ◽  
Degrees Of Freedom ◽  
Major Axis ◽  
The Body ◽  
Time Dependent ◽  
Triaxial Ellipsoid ◽  
Inviscid Fluid ◽  
Six Degrees Of Freedom ◽  
Ellipsoidal Harmonics ◽  
Unbounded Medium

The hydrodynamical forces and moments acting on a triaxial ellipsoid moving in an incompressible and inviscid fluid are analyzed. The rigid ellipsoid is allowed to move in the most general manner with time-dependent velocity and six degrees of freedom. The force and moment expressions are obtained by applying the Lagally theorem to the image singularities system representing the body in the presence of exterior disturbances. First, expressions for the Lagally force and moment acting on a maneuvering ellipsoid in an unbounded medium are derived and then these expressions are generalized to include the effect of an exterior source moving in an arbitrary manner. It is also shown how the Lagally expressions for an exterior source can be used to obtain closed-form expressions for the hydrodynamical forces and moments acting on a maneuvering ellipsoid in the presence of an arbitrary exterior disturbance. The analysis, which is based on the application of ellipsoidal harmonics, is demonstrated in a simple case of propeller-hull interaction. Here the motion of the ellipsoid is restricted to the major axis, and the propeller at the stern is represented by an isolated sink in accordance with Dickmann's model. 'Practical expressions for the thrust-deduction coefficient, wake fraction, and propeller-induced vibration are then derived for ellipsoidal, spheroidal and spherical hulls..

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