Astrophysics (Index)About

disk galaxy

(galaxy shaped like a flat circle)

Disk galaxy is a term for disk-shaped galaxies (e.g., as opposed to elliptical galaxies), including spiral galaxies, and including galaxies that are generally disk-shaped, even if they have a bulge, e.g., lenticular galaxy. The term disk refers to the galaxy's disk-like feature, often not intended to include the protrusions of the bulge.

Some analysis of observation suggests a majority of disk galaxies (including the Milky Way) comprise two overlaid disks of stars: a thick disk (i.e., thick disk stars), and within it, a thin disk (thin disk stars) that also includes gas, and dust. The thin disk stars are apparently younger, the result of more recent star formation.


(galaxy type)
Further reading:
http://en.wikipedia.org/wiki/Disc_galaxy
http://en.wikipedia.org/wiki/Thick_disk
http://en.wikipedia.org/wiki/Thin_disk

Referenced by pages:
bulge
circumgalactic medium (CGM)
disk
galactic disk
galactic plane
galactic tide
galaxy
galaxy classification
heating
lenticular galaxy (S0)
Lindblad torque
Milky Way
satellite plane problem
spiral galaxy
stellar dynamics
surface density (Σ)
Toomre Q parameter (Q)
warp

Index