Astrophysics (index)about

Protoplanetary Disk

(PPD, Planetary Disk, Proto-planetary Disk, Preplanetary Disk)
(disk of dust and gas around a young star or protostar)

A Protoplanetary Disk (or Preplanetary Disk) is a Circumstellar Disk, consisting of Dust and gas orbiting a young star or Protostar such as a T-Tauri Star. Radii can be as much as 1000 AU. Such disks are thought to provide the material for Planet Formation. The disks often develop a flared torus shape due to a combination of heat and Radiation Pressure from the central star. They can last several million years, evolving through Accretion, outflows, Photoevaporation, and/or condensation into larger bodies, small to large (Planetesimals or planets).

The term Proplyd is used for observed protoplanetary disks, visible for being illuminated, typically by the star's Ultraviolet radiation, resulting in Photodissociation ionization and Velocity Dispersion.

(disks,object type)

Referenced by:
Atmosphere Formation
Carbon Planet
Circumstellar Disk
Carbon Monoxide (CO)
Computational Astrophysics
Core Accretion Model
Debris Disk
Dynamical Instability
Gas Flow
Gravitational Instability Model
HL Tau
Hydrostatic Equilibrium
I Band
Infrared Space Observatory (ISO)
Meter Size Barrier
Orion Disks
Planetary Embryo
Planet Formation
Rossby Wave Instability (RWI)
Snow Line
Solar Nebula
Speckle Suppression
Stellar Age Determination
T-Tauri Star (TTS)