We define and analyze the photometric orbit (PhO) of an extrasolar planet observed in reflected light. In our definition, the PhO is a keplerian entity with six parameters: semimajor axis, eccentricity, mean anomaly at some particular time, argument of periastron, inclination angle, and effective radius, which is the square root of the geometric albedo times the planetary radius. Preliminarily,...

Although current sensitivity limits are such that true Solar System analogs remain challenging to detect, numerous planetary systems have been discovered that are very different from our own Solar System. The majority of systems harbor a new class of planets, bodies that are typically several times more massive than the Earth but that orbit their host stars well inside the orbit of Mercury. The...

Context. Kepler-444 is one of the oldest planetary systems known thus far. Its peculiar configuration consisting five sub-Earth-sized planets orbiting companion to a binary stellar system makes its early history puzzling. Moreover, observations HI-Ly α variations raise many questions about potential presence escaping atmospheres today. Aims. We aim study orbital evolution Kepler-444-d and Keple...

Past studies have demonstrated that atmospheric escape by the core-powered mass-loss mechanism can explain a multitude of observations associated with radius valley separates super-Earth and sub-Neptune planet populations. Complementing such studies, in this work, we present shortlist planets could be losing their atmospheres today if evolution is indeed primarily dictated mass-loss. We use Bay...

The linearized Kepler problem is considered, as obtained from the Kustaanheimo-Stiefel (K-S) transformation, both for negative and positive energies. The symmetry group for the Kepler problem turns out to be SU(2, 2). For negative energies, the Hamiltonian of Kepler problem can be realized as the sum of the energies of four harmonic oscillator with the same frequency, with a certain constrain. ...

The definitive ideas that led to the creation of general relativity crystallized in Einstein’s thinking during 1912 while he was in Prague. At the centenary meeting held there to mark the breakthrough, I was asked to talk about earlier great work of relevance to dynamics done at Prague, above all by Kepler and Mach. The main topics covered in this paper are: some little known but basic facts ab...

UNLABELLED As lower-mass stars often host multiple rocky planets, gravitational interactions among planets can have significant effects on climate and habitability over long timescales. Here we explore a specific case, Kepler-62f (Borucki et al., 2013 ), a potentially habitable planet in a five-planet system with a K2V host star. N-body integrations reveal the stable range of initial eccentrici...