Related papers: Why Wide Jupiter-Mass Binary-Objects Cannot Form

We report about an ongoing photometric and spectroscopic monitoring survey of about 250 O- and 540 B-type stars in the southern Milky Way with the aim to determine the fraction of close binary systems as a function of mass and to determine…

We investigate the formation and evolution of high-order massive star multiples similar to the Trapezium in the Orion Nebula Cluster. We perform ensembles of N-body simulations of the evolution of N=1000 Orion-like clusters with initial…

Radial velocity surveys find Jupiter mass planets with semi-major axes a less than 0.1 AU around ~1% of solar-type stars; counting planets with $a$ as large as 5 AU, the fraction of stars having planets reaches ~ 10% {Marcy,Butler}. An…

We investigate the formation of multiple-planet systems in the presence of a hot Jupiter using extended N-body simulations that are performed simultaneously with semi-analytic calculations. Our primary aims are to describe the planet…

"Free-floating, non-deuterium-burning, substellar objects" are isolated bodies of a few Jupiter masses found in very young open clusters and associations, nearby young moving groups and in the immediate vicinity of the Sun. They are neither…

Evidence of exoplanets with orbits that are misaligned with the spin of the host star may suggest that not all bound planets were born in the protoplanetary disk of their current planetary system. Observations have shown that free-floating…

We have collated multiplicity data for five clusters (Taurus, Chamaeleon I, Ophiuchus, IC348, and the Orion Nebula Cluster). We have applied the same mass ratio (flux ratios of delta K <= 2.5) and primary mass cuts (~0.1-3.0 Msun) to each…

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…

We explore two ways in which objects of planetary masses can form. One is in disk systems like the solar system. The other is in dense clusters where stars and brown dwarfs form. We do not yet have the instrumental accuracy to detect…

While Jupiter's massive gas envelope consists mainly of hydrogen and helium, the key to understanding Jupiter's formation and evolution lies in the distribution of the remaining (heavy) elements. Before the Juno mission, the lack of…

We know from observations that globular clusters are very efficient catalysts in forming unusual short-period binary systems or their offspring, such as low-mass X-ray binaries (LMXBs; neutron stars accreting matter from low-mass stellar…

We report the results of a deep near infrared (JHK) survey of the outer parts of the Trapezium Cluster with Gemini South/Flamingos. 396 sources were detected in a 26 arcmin^2 area, including 138 brown dwarf candidates, defined as M<0.075…

The discovery of high incidence of hot Jupiters in dense clusters challenges the field-based hot Jupiter formation theory. In dense clusters, interactions between planetary systems and flyby stars are relatively common. This has a…

We have performed a survey for substellar companions to young brown dwarfs in the Taurus star-forming region using the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. In these data, we have discovered a candidate…

Many massive objects have been found in the outer region of the Solar system. How they were formed and evolved has not been well understood, although there have been intensive studies on accretion process of terrestrial planets. One of the…

The origin of a recently discovered close-in Neptune-mass planet around GJ436 poses a challenge to the current theories of planet formation. Based on the sequential accretion hypothesis and the standard theory of gap formation and orbital…

The region around the H$_2$O ice line, due to its higher surface density, seems to be the ideal location to form planets. The core of Jupiter, as well as the cores of close in gas giants are thus thought to form in this region of the disk.…

The origin of hot Jupiters -- gas giant exoplanets orbiting very close to their host stars -- is a long-standing puzzle. Planet formation theories suggest that such planets are unlikely to have formed in-situ but instead may have formed at…

Circumbinary planets whose orbits become unstable may be ejected, accreted, or even captured by one of the stars. We quantify the relative rates of these channels, for a binary of secondary star's mass fraction 0.1 with an orbit of 1AU. The…

Of the > 500 confirmed transiting hot jupiters and approximately 2000 additional candidates today, only ten are known to have nearby companion planets. The survival of nearby companions means that these hot jupiters cannot have migrated to…