Accretion (astrophysics)
Videos
In astrophysics, accretion is the accumulation of matter into a massive object by gravitationally attracting more matter. If the matter is gaseous the result is an accretion disc. Accretion of solid m
ALMA image of HL Tauri, a protoplanetary disk
The visible-light (left) and infrared (right) views of the Trifid Nebula, a giant star-forming cloud of gas and dust located 5,400 light-years (1,700 pc) away in the constellation Sagittarius
Infrared image of the molecular outflow from an otherwise hidden newborn star HH 46/47
When the lower-mass star in a binary system enters an expansion phase, its outer atmosphere may fall onto the compact star, forming an accretion disk
Planetesimal
Videos
Planetesimals are solid objects thought to exist in protoplanetary disks and debris disks. Believed to have formed in the Solar System about 4.6 billion years ago, they aid study of its formation.
Accretion (astrophysics)
…the different stages of terrestrial planet formation. Since then, the model has been further developed using intensive numerical simulations to study planetesimal accumulation. It is now accepted that stars form by the gravitational collapse of interstellar gas. Prior to collapse, this gas is mostly in the form…
Debris disks detected in HST archival images of young stars, HD 141943 and HD 191089, using improved imaging processes (24 April 2014)
PDS 70