SSPSF model
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The SSPSF model of star formation was proposed by Mueller & Arnett in 1976, generalized afterward by Gerola & Seiden in 1978 and Gerola, Seiden, & Schulman in 1980. This model proposes that star forma
This image from NASA Spitzer Space Telescope shows the supernova remnant Henize 206, in which new stars heat the gas.
In 1995, the spiral galaxy NGC 4414 was imaged by the Hubble Space Telescope.
Density wave theory
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Density wave theory or the Lin–Shu density wave theory is a theory proposed by C.C. Lin and Frank Shu in the mid-1960s to explain the spiral arm structure of spiral galaxies. The Lin–Shu theory introd
SSPSF model
…emission shows where a new generation of stars heats the remains of the supernova remnant that induced their formation. In contrast to star formation in density-wave theories, which are limited to disk-shaped galaxies and produce global spiral patterns, SSPSF applies equally well to spirals, to irregular galaxies and to any…
Image of spiral galaxy M81 combining data from the Hubble, Spitzer, and GALEX space telescopes.
Spiral density waves in Saturn's A Ring induced by resonances with nearby moons.