Bulges that have properties similar to elliptical galaxies are often called classical bulges due to their similarity to the historic view of bulges. These bulges are composed primarily of stars that are older population II stars, and hence have a reddish hue (see stellar evolution). These stars are also in orbits that are essentially random compared to the plane of the galaxy, giving the bulge a distinct spherical form. Due to the lack of dust and gasses, bulges tend to have almost no star formation. The distribution of light is described by de Vaucouleurs' law.
Classical bulges are thought to be the result of collisions of smaller structures. This disrupts the path of the stars, resulting in the randomness of bulge orbits. Also during the merger, gas clouds are more likely to be converted into stars, due to the shocks from the mergers (see Star Formation).
Read more about this topic: Bulge (astronomy)
Famous quotes containing the words classical and/or bulges:
“Et in Arcadia ego.
[I too am in Arcadia.]”
—Anonymous, Anonymous.
Tomb inscription, appearing in classical paintings by Guercino and Poussin, among others. The words probably mean that even the most ideal earthly lives are mortal. Arcadia, a mountainous region in the central Peloponnese, Greece, was the rustic abode of Pan, depicted in literature and art as a land of innocence and ease, and was the title of Sir Philip Sidney’s pastoral romance (1590)
“There in the narrow,
mote-filled finger of light, is a blonde
so blonde, so blinding, she is a blizzard, a huge
spook, and lights up like the sun the audience
in its galoshes. She bulges like a deuce coupe.
When we see her we say good-bye to Kansas.”
—Lynn Emanuel (b. 1949)