Related papers: Ninth Planet or Wandering Star ?
All planets and satellites of our solar system are subject to a continuous rain of material, ranging in size from specks of dust to objects the size of boulders. Upon impact, these objects deposit their kinetic energy into the incident…
Observations of the Kuiper Belt indicate that a larger than expected percentage of KBO's (approximately 8 out of 500) are in binary pairs. The formation and survival of such objects presents a conundrum [1]. Two competing theories have been…
A quarter of DA white dwarfs are metal polluted, yet elements heavier than helium sink down through the stellar atmosphere on timescales of days. Hence, these white dwarfs must be currently accreting material containing heavy elements.…
As many as $10^9$ neutron stars populate the Galaxy, but only $\approx 10^3$ are directly observed as pulsars or as accreting sources in X-ray binaries. In principle also the accretion of the interstellar medium may make isolated neutron…
Although gravitational waves only interact weakly with matter, their propagation is affected by a gravitational potential. If a gravitational wave source is eclipsed by a star, measuring these perturbations provides a way to directly…
If planetary systems are ubiquitous then a fraction of stars should possess a transiting planet when being microlensed. This paper presents a study of the influence of such planets on microlensing light curves. For the giant planets…
The presence of debris disks around $\sim$ 1-Gyr-old main sequence stars suggests that an appreciable amount of dust may persist even in mature planetary systems. Here we report the detection of dust emission from 55 Cancri, a star with…
Planets in highly eccentric orbits form a class of objects not seen within our Solar System. The most extreme case known amongst these objects is the planet orbiting HD~20782, with an orbital period of 597~days and an eccentricity of 0.96.…
Several anomalous features in the orbital distribution of distant Kuiper Belt objects have recently sparked suggestions of an unseen large planet (or two) orbiting beyond Neptune. I review the theoretical arguments and the prospects for the…
We investigate gravitational lensing effects of an extrasolar planet transiting its host star. We focus on the `rising spikes' of the light curve just before and after the transit, which is a peculiar feature of the gravitational lensing,…
In an effort to measure the masses of planets discovered by the NASA {\it K2} mission, we have conducted precise Doppler observations of five stars with transiting planets. We present the results of a joint analysis of these new data and…
The formation of the largest objects in the Kuiper belt, with measured densities of ~1.5 g cm-3 and higher, from the coagulation of small bodies, with measured densities below 1 g cm-3 is difficult to explain without invoking significant…
Mounting discoveries of extrasolar planets orbiting post-main sequence stars motivate studies aimed at understanding the fate of these planets. In the traditional "adiabatic" approximation, a secondary's eccentricity remains constant during…
We have measured radial velocities of a star, OGLE-TR-56, which shows a 1.2-day transit-like light curve found photometrically by Udalski et al.(2002ab). Here we show that the velocity changes we detect are probably induced by an object of…
According to the cosmological principle, the Universe should appear isotropic, without any preferred directions, to an observer whom we may consider to be fixed in the co-moving co-ordinate system of the expanding Universe. Such an observer…
Our current knowledge of the dynamical structure of the Kuiper Belt is reviewed here. Numerical results on long term orbital evolution and dynamical mechanisms underlying the transport of objects out of the Kuiper Belt are discussed.…
There are hints of a novel object ("Planet 9") with a mass $5-10$ $M_\oplus$ in the outer Solar System, at a distance of order 500 AU. If it is a relatively conventional planet, it can be found in telescopic searches. Alternatively, it has…
We analyze the effect of companion stars on the bulk density of 29 planets orbiting 15 stars in the Kepler field. These stars have at least one stellar companion within 2", and the planets have measured masses and radii, allowing an…
Determining whether Earth-like planets are common or rare looms as a touchstone in the question of life in the universe. We searched for Earth-size planets that cross in front of their host stars by examining the brightness measurements of…
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,…