Related papers: A gaseous metal disk around a white dwarf
Although there is abundant and diverse observational evidence in support of white dwarf stars hosting planets or debris disks which form in the catastrophic destruction of various planetary bodies, the key processes that explain these…
Increasing observations of white dwarf atmospheric pollution and disrupting planetesimals is driving increased studies into the fate of exo-asteroids around post-main-sequence stars. Planetesimal populations in the Solar System which are…
Eighteen years after an infrared excess was discovered associated with the white dwarf G29-38, we report ground-based measurements (JHKL'N') with mJy-level sensitivity of GD 362 that show it to be a second single white dwarf with an…
There is increasing evidence for the presence and variability of circumstellar dust and gas around white dwarfs that are polluted with exoplanetary material, although the origin of this dust and gas remains debated. This paper presents the…
It was recently proposed that metal-rich white dwarfs (WDs) accrete their metals from compact debris disks found to exist around more than a dozen of them. At the same time, elemental abundances measured in atmospheres of some WDs imply…
We report the discovery of excess K-band radiation from a massive DAZ white dwarf star, GD362. Combining infrared photometric and spectroscopic observations, we show that the excess radiation cannot be explained by a stellar or substellar…
Debris disks are the dust disks found around ~20% of nearby main sequence stars in far-IR surveys. They can be considered as descendants of protoplanetary disks or components of planetary systems, providing valuable information on…
Small exoplanet radii show two populations, referred to as super-Earths and sub-Neptunes, separated by a gap known as the radius valley. This may be produced by the removal of atmospheres due to stellar or internal heating, or lack of an…
The existence of water in extrasolar planetary systems is of great interest as it constrains the potential for habitable planets and life. Here, we report the identification of a circumstellar disk that resulted from the destruction of a…
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…
We performed an uniform spectroscopic analysis of 1111 FGK dwarfs observed as part of the HARPS GTO planet search program. We applied a purely chemical approach, based on [alpha/Fe] ratio, to distinguish the various stellar components in…
The Galactic centre hosts, according to observations, a number of early-type stars. About one half of those which are orbiting the central supermassive black hole on orbits with projected radii $\gtrsim$ 0.03 pc form a coherently rotating…
(Abridged) Giant planets are observed orbiting the primary stars of close binary systems. Such planets may have formed in compact circumprimary disks, under conditions much different than those around single stars. To quantify the effects…
During their formative stages, giant planets are fed by infalling material sourced from the background circumstellar disk. Due to conservation of angular momentum, the incoming gas and dust collects into a circumplanetary disk that…
Observational studies showed that galaxy disks are already in place in the first few billion years of the universe. The early disks detected so far, with typical half-light radii of 3 kiloparsecs at stellar masses around 10^11 M_sun for…
There is a wealth of evidence to suggest that planetary systems can survive beyond the main sequence. Most commonly, white dwarfs are found to be accreting material from tidally disrupted asteroids, whose bulk compositions are reflected by…
We show that interaction with a gas disk may produce young planetary systems with closely-spaced orbits, stabilized by mean-motion resonances between neighbors. On longer timescales, after the gas is gone, interaction with a remnant…
We propose a scenario to form low-mass, single, slow rotating white dwarfs from a solar-like star accompanied by a massive planet, or a brown dwarf, in a relatively close orbit (e.g. HD 89707). Such white dwarfs were recently found by…
The edge-on disk surrounding the nearby young star Beta Pictoris is the archetype of the "debris disks", which are composed of dust and gas produced by collisions and evaporation of planetesimals, analogues of Solar System comets and…
We present preliminary results from our spectroscopic search for planets within 1 AU of metal-poor field dwarfs using NASA time with HIRES on Keck I. The core accretion model of gas giant planet formation is sensitive to the metallicity of…