A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young star that has just formed. Protoplanetary disks have radii up to 1000 AU. Protoplanetary disks have been seen around several young stars in our galaxy.
Protoplanetary disks are thought to be thin structures. They have mass that is much smaller than the young star in the center.
- Ricci, L.; Robberto, M.; Soderblom, D. R. (2008-11-01). "THE HUBBLE SPACE TELESCOPE /ADVANCED CAMERA FOR SURVEYS ATLAS OF PROTOPLANETARY DISKS IN THE GREAT ORION NEBULA". The Astronomical Journal. 136 (5): 2136–2151. doi:10.1088/0004-6256/136/5/2136. ISSN 0004-6256.
- Armitage, Philip J. (2011-09-22). "Dynamics of Protoplanetary Disks". Annual Review of Astronomy and Astrophysics. 49 (1): 195–236. doi:10.1146/annurev-astro-081710-102521. ISSN 0066-4146.