Related papers: Hierarchical Eclipses
Astrophysical fluid bodies that orbit close to one another induce tidal distortions and flows that are subject to dissipative processes. The spin and orbital motions undergo a coupled evolution over astronomical timescales, which is…
The rotation of a star and the revolutions of its planets are not necessarily aligned. This article reviews the measurement techniques, key findings, and theoretical interpretations related to the obliquities (spin-orbit angles) of…
A large sample of planet-planet scattering events for three planet systems with different orbital separations and masses is analyzed with a multiple regression model. The dependence of the time for the onset of instability on the masses of…
A time-dependent gravitational constant or mass would correctly describe the suspected increasing of both: the Astronomical unit and the eccentricity of the Lunar orbit around the Earth.
There is accumulating evidence that the faint end of the galaxy luminosity function might be very different in different locations. The luminosity function might be rising in rich clusters and flat or declining in regions of low density. If…
Apart from thousands of `regular' exoplanet candidates, Kepler satellite has discovered a few stars exhibiting peculiar eclipse-like events. They are most probably caused by disintegrating bodies transiting in front of the star. However,…
The shadow of a black hole is usually calculated, either analytically or numerically, on the assumption that the black hole is eternal, i.e., that it existed for all time. Here we ask the question of how this shadow comes about in the…
In condensed matter systems, the atoms, electrons or spins can sometimes arrange themselves in ways that result in unexpected properties but that cannot be detected by conventional experimental probes. Several historical and contemporary…
Imaging of planets is very difficult, due to the glare from their nearby, much brighter suns. Static and slowly-evolving aberrations are the limiting factors, even after application of adaptive optics. The residual speckle pattern is highly…
Comets, asteroids and moons that orbit stars and planets exterior to our solar system are prefixed with "exo". While the existence of these objects is certain, our understanding of their physical properties, composition, and diversity is…
We model the secular evolution of a star's orbit when it has a nearby binary system. We assume a hierarchical triple system where the inter-binary distance is small in comparison with the distance to the star. We show that the major secular…
In the last few years, a number of planets have been proposed to orbit several post main-sequence binary star systems on the basis of observed variations in the timing of eclipses between the binary components. A common feature of these…
Planets accompany most sun-like stars. The orbits of many are sufficiently close that they will be engulfed when their host stars ascend the giant branch. This Letter compares the power generated by orbital decay of an engulfed planet to…
The moon, moonlight, phases of the moon and its relatively simple recurring cycle has been of interest since time immemorial to the human beings, navigators, astronomers and astrologers. The fact that its orbit is elliptical as well its…
Extinction is the elephant in the room that almost everyone tries to avoid when analyzing optical/IR data: astronomers tend to find a quick fix for it that the referee will accept, but that does not mean such a solution is correct or even…
We report the discovery with TESS of a remarkable quadruple star system with a 2+1+1 configuration. The two unique characteristics of this system are that (i) the inner eclipsing binary (stars Aa and Ab) eclipses the star in the outermost…
If one asked some friends where on the horizon they should expect to see the sunrise, half of the answers would be "in the east". Of course, something analogous would happen with the sunset and the west. However, sunrise and sunset…
We investigate the anomalies in the Earth - Moon system using ancient eclipse data. We identify nine groups of anomalous eclipses between 400 and 1800 AD recorded in parts of India that should have completely missed the subcontinent as per…
Photon spheres play a pivotal role in the imaging of luminous objects near black holes. In this paper, we examine observational appearances of a star freely falling in hairy black holes, which can possess one or two photon spheres outside…
We investigate the properties of microlensing events caused by planetary systems where planets with a moon are widely separated from their host stars. From this investigation, we find that the moon feature generally appears as an very…