Thick disk

The thick disk is one of the structural components of several galaxies, including the Milky Way. It was first proposed as a unique galactic structure, different from the thin disk and the halo in an 1983 article by Gilmore & Reid. It is supposed to dominate the stellar number density between 1 to 5 kiloparsecs (3.3 to 16.3 kly) above the Galactic plane and is composed almost exclusively of older stars. Its chemical composition and kinematics (those of the stars comprising it) are also said to set it apart from the thin disk. Stars within the thick disk may be called old-disk stars. Compared to stars in the thin disk, these typically have a significantly lower levels of metals—that is, the abundance of elements other than hydrogen and helium.

The thick disk is a source of early kinematic and chemical evidence for a Galaxy's composition and thus is regarded as a very significant component for understanding Galaxy formation.

Origin

Various scenarios for the formation of this structure have been proposed, including:

Thick

Thick may refer to:

See also

Thick (album)

Thick is an album by the fusion jazz band Tribal Tech released in 1999. As a contrast to Tribal Tech's previous recordings, the album features less compositional material and is based largely on improvization.

Track listing

All tracks composed by Scott Henderson, Gary Willis, Scott Kinsey and Kirk Covington.

Personnel

References

Disc

Disc or disk (computing and American English) may refer to:

Data storage

Disc (band)

Disc is an experimental group formed by Miguel Depedro (Kid606), Jason Doerck (J Lesser), M. C. Schmidt and Drew Daniel (Matmos). The group was most active between 1997 and 1999.

To produce their sound, digital media (DATs, CDs) were etched and painted, or used in broken players to produce new sounds. In Gaijincd4, a "bonus" nonfunctional CD was included to suggest a multimedia disc. The double LP Transfer consisted entirely of locked grooves.

Discography

Albums

External links

Disc (galaxy)

A disc is a component of disc galaxies, such as spiral galaxies, or lenticular galaxies.

The galactic disc is the plane in which the spirals, bars and discs of disc galaxies exist. Galactic discs tend to have more gas and dust and younger stars than galactic bulges or galactic haloes.

The galactic disc is mainly composed of gas, dust and stars. The gas and dust component of the galactic disc is called the gaseous disc. The star component of the galactic disc is called the stellar disc.

Inconsistent orbital velocities of stars

It has been noted that the orbital velocity of stars in the disc of most disc galaxies is inconsistent with the amount of luminous matter calculated for the galaxy. A possible explanation for this problem is the non-luminous dark matter.

See also

Further reading