Related papers: High speed escape from a circular orbit
The fact that the spatial velocity of pulsars is generally higher than that of their progenitor stars has bothered astronomers for nearly 50 years. It has been extensively argued that the high pulsar velocity should be acquired during a…
A Dyson ring is a hypothetical megastructure, that a very advanced civilization would build around a star to harness more of its energy. Satellite propagation is of high priority in such a vast world where distances could very well be…
In the context of a star cluster moving on a circular galactic orbit, a "potential escaper" is a cluster star that has orbital energy greater than the escape energy, and yet is confined within the Jacobi radius of the stellar system. On the…
Gravity-Assisted maneuvers have been used as a technique to reduce fuel consumption in deep space missions for several decades now. It opened the doors of the exterior solar system. The literature shows those results, as well as new…
A particle in the H\'enon-Heiles potential can escape when its energy is above the threshold value $E_{th}={1/6}$. We report a theoretical study on the the escape rates near threshold. We derived an analytic formula for the escape rate as a…
Massive black holes have been discovered in all closely examined galaxies with high velocity dispersion. The case is not as clear for lower-dispersion systems such as low-mass galaxies and globular clusters. Here we suggest that above a…
In the high-eccentricity migration (HEM) scenario, close-in planets reach the vicinity of the central star on high-eccentricity orbits that become circularized---with a concomitant decrease in the semimajor axis---through a tidal…
Gas giant planets have been detected on eccentric orbits several hundreds of astronomical units in size around other stars. It has been proposed that even the Sun hosts a wide-orbit planet of 5-10 Earth masses, often called Planet Nine,…
We propose the Wind of Fast Rotating Massive Stars scenario to explain the origin of the abundance anomalies observed in globular clusters. We compute and present models of fast rotating stars with initial masses between 20 and 120 Msun for…
An orbitope is the convex hull of an orbit of a compact group acting linearly on a vector space. These highly symmetric convex bodies lie at the crossroads of several fields, in particular convex geometry, optimization, and algebraic…
The shell bound by the Karman line at a height of 80 to 100km above the Earth's surface, and Geosynchronous Orbit, at 36,000km, is defined as the orbital space surrounding the Earth. It is within this region, and especially in Low Earth…
Blazars are sources whose jet is pointing to us. Since their jets are relativistic, the flux is greatly amplified in the direction of motion, making blazars the most powerful persistent objects in the Universe. This is true at all…
We compute the ultra-high energy cosmic ray horizon, i.e. the distance up to which cosmic ray sources may significantly contribute to the fluxes above a certain threshold on the observed energies. We obtain results both for proton and heavy…
The aim of this paper is to determine the initial rotational velocities required on the ZAMS for single stars to reach the critical velocity, sometimes called the break-up velocity, during the Main-Sequence (MS) phase. Some useful relations…
The aim of this work is to compare the orbital dynamics in three different models describing the properties of a star cluster rotating around its parent galaxy in a circular orbit. In particular, we use the isochrone and the Hernquist…
In this paper, we show that the eccentricity of a planet on an inclined orbit with respect to a disc can be pumped up to high values by the gravitational potential of the disc, even when the orbit of the planet crosses the disc plane. This…
Radial Velocity follow-up is essential to establish or exclude the planetary nature of a transiting companion as well as to accurately determine its mass. Here we present some elements of an efficient Doppler follow-up strategy, based on…
The manuscript provides formulas for the volume of a body defined by the intersection of a solid cone and a solid sphere as a function of the sphere radius, of the distance between cone apex and sphere center, and of the cone aperture…
Several of the models for origin of the highest energy cosmic rays also predict significant neutrino fluxes. A common factor of the models is that they must provide sufficient power to supply the observed energy in the extragalactic…
A technique by which a spacecraft can interact with flows of ionized gas in space (the solar wind or interstellar medium) to be accelerated to velocities greater than the wind velocity is explored. Inspired by the dynamic soaring maneuvers…