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The equilibrium rotation of tidally evolved "Earth-like" extra-solar planets is often assumed to be synchronous with their orbital mean motion. The same assumption persisted for Mercury and Venus until radar observations revealed their true…
The alignment of planetary orbits with respect to the stellar rotation preserves information on their dynamical histories. Measuring this angle for young planets help illuminate the mechanisms that create misaligned orbits for older…
The tilt of a planet's spin axis off its orbital axis ("obliquity") is a basic physical characteristic that plays a central role in determining the planet's global circulation and energy redistribution. Moreover, recent studies have also…
Half the known extrasolar planets have orbital eccentricities in excess of 0.3. Such large eccentricities are surprising as it is thought that planets form in a protoplanetary disk on nearly circular orbits much like the current states of…
Astronomers do not have a complete picture of the effects of wide-binary companions (semimajor axes greater than 100 AU) on the formation and evolution of exoplanets. We investigate these effects using new data from Gaia EDR3 and the TESS…
Tsiganis et al. (2005) have proposed that the current orbital architecture of the outer solar system could have been established if it was initially compact and Jupiter and Saturn crossed the 2:1 orbital resonance by divergent migration.…
It is shown herein that planets with eccentric orbits are more likely to transit than circularly orbiting planets with the same semimajor axis by a factor of (1-e^2)^{-1}. If the orbital parameters of discovered transiting planets are…
Context. The paths followed by the known extreme trans-Neptunian objects (ETNOs) effectively avoid direct gravitational perturbations from the four giant planets, yet their orbital eccentricities are in the range between 0.69-0.97. Solar…
We report 18 years of Doppler shift measurements of a nearby star, 55 Cancri, that exhibit strong evidence for five orbiting planets. The four previously reported planets are strongly confirmed here. A fifth planet is presented, with an…
Transit surveys have revealed a significant population of compact multi-planet systems, containing several sub-Neptune-mass planets on close-in, tightly-packed orbits. These systems are thought to have formed through a final phase of giant…
We report the discovery of the first trans-neptunian object, designated 2004 XR190, with a nearly-cirular orbit beyond the 2:1 mean-motion resonance. Fitting an orbit to 23 astrometric observations spread out over 12 months yields an orbit…
The Kuiper belt includes tens of thousands of large bodies and millions of smaller objects. The main part of the belt objects is located in the annular zone between 39.4 au and 47.8 au from the Sun, the boundaries correspond to the average…
The post-main sequence eclipsing binary NN Serpentis was recently announced as the potential host of at least two massive planetary companions. In that work, the authors put forward two potential architectures that fit the observations of…
Theories of the formation and early evolution of planetary systems postulate that planets are born in circumstellar disks, and undergo radial migration during and after dissipation of the dust and gas disk from which they formed. The…
We analytically work out the long-term orbital perturbations induced by a homogeneous circular ring of radius Rr and mass mr on the motion of a test particle in the cases (I): r > R_r and (II): r < R_r. In order to extend the validity of…
We report a transiting extrasolar giant planet around the star OGLE-TR-10 (orbital period = 3.1 days), which was uncovered as a candidate by the OGLE team in their photometric survey towards the Galactic center (Udalski et al, 2002a). We…
Tumbling asteroids belong to a small group of objects, whose angular velocity vector is unaligned with any of its principal axes of inertia. This leads to challenging efforts to model the trajectory of any spacecraft designed to orbit these…
From the numerous detected planets outside the Solar system, no terrestrial planet comparable to our Earth has been discovered so far. The search for an Exo-Earth is certainly a big challenge which may require the detections of planetary…
The orbital structure of the asteroid belt holds a record of the Solar System's dynamical history. The current belt only contains ${\rm \sim 10^{-3}}$ Earth masses yet the asteroids' orbits are dynamically excited, with a large spread in…
In general relativity, the Mercury's orbit becomes approximately elliptical and the its perihelion has thus an additional advance. We demonstrate, meanwhile, that in comparison of those given by the Newton's theory of gravitation for the…