Related papers: Forming the first planetary systems: debris around…
Circumstellar dust disks have been observed around many nearby stars. However, many stars are part of binary or multiple stellar systems. A natural question arises regarding the presence and properties of such disks in systems with more…
Circumstellar disks of planetary debris are now known or suspected to closely orbit hundreds of white dwarf stars. To date, both data and theory support disks that are entirely contained within the preceding giant stellar radii, and hence…
We have carried out a sensitive search for gas emission lines at infrared and millimeter wavelengths for a sample of 15 young sun-like stars selected from our dust disk survey with the Spitzer Space Telescope. We have used mid-infrared…
Planetesimals form in gas-rich protoplanetary disks around young stars. However, protoplanetary disks fade in about 10 Myr. The planetesimals (and also many of the planets) left behind are too dim to study directly. Fortunately, collisions…
Two decades of effort have been poured into both single-dish and interferometric millimeter-wave surveys of the sky to infer the volume density of dusty star-forming galaxies (DSFGs, with SFR>100M$_\odot$ yr$^{-1}$) over cosmic time. Though…
Observations of massive stars within the central parsec of the Galaxy show that, while most stars orbit within a well-defined disc, a significant fraction have large eccentricities and / or inclinations with respect to the disc plane. Here,…
Circumstellar disks have long been regarded as windows into planetary systems. The advent of high sensitivity, high resolution imaging in the submillimetre where both the solid and gas components of disks can be detected opens up new…
Over the past 10 years abundant evidence has emerged that many (if not all) stars are born with circumstellar disks. Understanding the evolution of post-accretion disks can provide strong constraints on theories of planet formation and…
Well before the existence of exo-solar systems was confirmed, it was accepted knowledge that most -- if not all -- stars possess circumstellar material during the first one-to-several million years of their pre-main sequence lives, and thus…
Several hundred stars older than 10 million years have been observed to have infrared excesses. These observations are explained by dust grains formed by the collisional fragmentation of hidden planetesimals. Such dusty planetesimal discs…
Exoplanet demographic surveys have revealed that close-in (${\lesssim}$1 au) small planets orbiting stars in the Milky Way's thick disk are ${\sim}50\%$ less abundant than those orbiting stars in the Galactic thin disk. One key difference…
[Abridged] We map the stellar age distribution ($\lesssim 1$ Gyr) across a 6kpc$\,\times\,$6kpc area of the Galactic disc to constrain our Galaxy's recent star-formation history. Our modelling draws on the sample of Zari et al. (2021) that…
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…
Debris disks are exoplanetary systems containing planets, minor bodies (such as asteroids and comets) and debris dust. Unseen planets are presumed to perturb the minor bodies into crossing orbits, generating small dust grains that are…
Protoplanetary disks are thought to be the birth places of planetary systems. The formation and the subsequent evolution of protoplanetary disks are regulated by the star formation process, which begins with the collapse of a cloud core to…
Kant and Laplace suggested the Solar System formed from a rotating gaseous disk in the 18th century, but convincing evidence that young stars are indeed surrounded by such disks was not presented for another 200 years. As we move into the…
Until recently it was thought that the nuclear stellar disc at the centre of our Galaxy was formed via quasi-continuous star formation over billions of years. However, an analysis of GALACTICNUCLEUS survey data indicates that >80% of the…
The behavior of the relative magnesium abundances in the thin-disk stars versus their orbital radii suggests that the star formation rate in the thin disk decreases with increasing Galactocentric distance, and there was no star formation…
Observations of dusty debris disks can be used to test theories of planetesimal coagulation. Planetesimals of sizes up to a couple thousand kms are embedded in these disks and their mutual collisions generate the small dust grains that are…
At redshift z = 2, when the Universe was just three billion years old, half of the most massive galaxies were extremely compact and had already exhausted their fuel for star formation(1-4). It is believed that they were formed in intense…