Related papers: Dynamical Constraints on the HR 8799 Planets with …

The three-planet extrasolar system of HD 181433 has been detected with HARPS. The best-fit solution, announced by the discovery team, describes a highly unstable, self-disrupting configuration. In fact, a narrow observational window, only…

The orbits in the HD 160691 planetary system at first appeared highly unstable, but using the MEGNO and FLI techniques of global dynamics analysis in the orbital parameter space we have found a stabilizing mechanism that could be the key to…

Giant, wide-separation planets often lie in the gap between multiple, distinct rings of circumstellar debris: this is the case for the HR\,8799 and HD\,95086 systems, and even the solar system where the Asteroid and Kuiper belts enclose the…

We have performed simulations to investigate the dynamics of the M dwarf star GJ 876 in an attempt to reveal any stabilizing mechanism for sustaining the system.We simulated different coplanar and noncoplanar configurations of two-planet…

The near-infrared colors of the planets directly imaged around the A star HR 8799 are much redder than most field brown dwarfs of the same effective temperature. Previous theoretical studies of these objects have concluded that the…

We perform a dynamical analysis of the recently published radial velocity (RV) measurements of a few solar type stars which host multiple Jupiter-like planets. In particular, we re-analyze the data for HD 202206, 14 Her, HD 37124 and HD…

A possible polar-ring debris disc, the dynamics of which can be described by the outer hierarchical restricted three-body problem, has been detected in 99 Herculis. An empirical formula on the minimum radius beyond which test particles in…

The number of multi-planet systems known to be orbiting their host stars with orbital periods that place them in mean motion resonances is growing. For the most part, these systems are in first-order resonances and dynamical studies have…

A fraction of multiple planet candidate systems discovered from transits by the Kepler mission contain pairs of planet candidates that are in orbital resonance or are spaced slightly too far apart to be in resonance. We focus here on the…

The recent discoveries of massive planets on ultra-wide orbits of HR 8799 (Marois et al. 2008) and Fomalhaut (Kalas et al. 2008) present a new challenge for planet formation theorists. Our goal is to figure out which of three giant planet…

The discovery of three planetary companions around HR 8799 (Marois et al. 2008) marked a significant epoch in direct imaging of extrasolar planets. Given the importance of this system, we re-analyzed H band images of HR 8799 obtained with…

Context. Astrometric monitoring of directly-imaged exoplanets allows the study of their orbital parameters and system architectures. Because most directly-imaged planets have long orbital periods (>20 AU), accurate astrometry is challenging…

HR~8799 is a young F0-type star with four directly imaged giant planets and two debris belts, one located exterior and another one interior to the region occupied by the planetary orbits. Having an architecture similar to that of our Solar…

We have numerically explored the stable planetary geometry for the multiple systems involved in a 2:1 mean motion resonance, and herein we mainly study the HD 82943 system by employing two sets of the orbital parameters (Mayor et al. 2004;…

We report the discovery of two giant planets orbiting the K giant HD 33844 based on radial velocity data from three independent campaigns. The planets move on nearly circular orbits with semimajor axes $a_b=1.60\pm$0.02 AU and…

This paper explores the stability of an Earth-like planet orbiting a solar mass star in the presence of an outer-lying intermediate mass companion. The overall goal is to estimate the fraction of binary systems that allow Earth-like planets…

Long time coverage and high radial velocity precision have allowed for the discovery of additional objects in known planetary systems. Many of the extrasolar planets detected have highly eccentric orbits, which raises the question of how…

The search for exoplanets has revealed a diversity of planetary system architectures, the vast majority of which diverge significantly from the template of the solar system. In particular, giant planets beyond the snow line are relatively…

We report the detection of a new planetary system orbiting the nearby M2.5V star GJ357, using precision radial-velocities from three separate echelle spectrographs, HARPS, HiRES, and UVES. Three small planets have been confirmed in the…

(Abreviated) Continued radial velocity monitoring of the nearby M4V red dwarf star GJ~876 with Keck/HIRES has revealed the presence of a Uranus-mass fourth planetary companion in the system. The new planet has a mean period of $P_e=126.6$…