Related papers: A clock model for planetary conjunctions
The ability of digital sky surveys to collect and store very large amounts of data provides completely new ways to study the local universe. Perhaps one of the most provocative observations reported with such tools is the asymmetry between…
We propose a cosmological model in which the universe undergoes an endless sequence of cosmic epochs each beginning with a `bang' and ending in a `crunch.' The temperature and density are finite at each transition from crunch to bang.…
In the coming decades, the discovery of the first truly Earth-like exoplanets is anticipated. The characterisation of those planets will play a vital role in determining which are chosen as targets for the search for life beyond the Solar…
Many of the multi-planet systems discovered to date have been notable for their compactness, with neighbouring planets closer together than any in the Solar System. Interestingly, planet-hosting stars have a wide range of ages, suggesting…
(Abridged) The solar system gas giant planets are oblate due to their rapid rotation. A measurement of the planet's projected oblateness would constrain the planet's rotational period. Planets that are synchronously rotating with their…
The extremely close proximity of hot Jupiters to their parent stars has dramatically affected both their atmospheres and interiors, inflating them to up to twice the radius of Jupiter. The physical mechanism responsible for this inflation…
Hot Jupiters are giant planets on orbits a few hundredths of an AU. They do not share their system with low-mass close-in planets, despite these latter being exceedingly common. Two migration channels for hot Jupiters have been proposed:…
We find an interesting fact that fictitious retrograde co-orbitals of Saturn, or small bodies inside the retrograde 1:1 resonance with Saturn, are highly unstable in our numerical simulations. It is shown that in the presence of Jupiter,…
The discovery of Jupiter-mass planets in close orbits about their parent stars has challenged models of planet formation. Recent observations have shown that a number of these planets have highly inclined, sometimes retrograde orbits about…
Based on the large number of elliptical planetary nebulae I argue that about 55 per cent of all progenitors of planetary nebulae have planets around them. The planets spin up the stars when the later evolve along the red giant branch or…
Warm giant planets with orbital periods of tens of days exhibit a positive correlation between mass and eccentricity. We interpret this trend as the outcome of planet-planet scattering, representing a transition from collision-dominated…
In protoplanetary disks, sufficiently massive planets excite pressure bumps, which can then be preferred locations for forming new planet cores. We discuss how this loop may affect the architecture of multi-planet systems, and compare our…
Many have have taken in hand to write a treatise on the Star of Bethlehem, particularly on Kepler's explanation as a stellar birth, triggered by Mars joining a great conjunction (a meeting of Jupiter and Saturn), as he observed it in…
The 2020s will be the most data-rich decade of astronomy in history. As the scale and complexity of our surveys increase, the problem of scheduling becomes more critical. We must develop high-quality scheduling approaches, implement them as…
Recent observations have indicated a strong connection between compact ($a \lesssim 0.5$ au) super-Earth and mini-Neptune systems and their outer ($a \gtrsim$ a few au) giant planet companions. We study the dynamical evolution of such inner…
Planet obliquity is the alignment or misalignment of a planet spin axis relative to its orbit normal. In a multiplanet system, this obliquity is a valuable signature of planet formation and evolutionary history. The young $\beta$ Pictoris…
More than two decades after the widespread detection of Jovian-class planets on short-period orbits around other stars, their dynamical origins remain imperfectly understood. In the traditional narrative, these highly irradiated giant…
(abbreviated) We use a semi-numerical approach to study the secular behavior of a system composed of a central star and two massive planets in eccentric co-planar orbits. We show that the secular dynamics of this system can be described…
Recent measurements of Jupiter's gravitational moments by the Juno spacecraft and seismology of Saturn's rings suggest that the primordial composition gradients in the deep interior of these planets have persisted since their formation. One…
Recent observations suggest that stellar magnetic activity may be influenced by the presence of a close-by giant planet. Specifically, chromospheric hot spots rotating in phase with the planet orbital motion have been observed during some…