Hercules stream
Encyclopedia
Hercules stream is a large moving group of star
s that are trailing behind the local rate of galactic rotation and are heading further out in the disk. Members of this stream may sometimes be referred to as Hercules stars. This stream was first hypothesized to be the remnants of a cluster of
stars that has evaporated over time, becoming gravitationally unbound. Alternatively, the Hercules stream may have been created as a resonant effect of the galactic bar
at the center of the Milky Way
. This stream
of stars has a space velocity component V equal to about −40 km/s.
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s that are trailing behind the local rate of galactic rotation and are heading further out in the disk. Members of this stream may sometimes be referred to as Hercules stars. This stream was first hypothesized to be the remnants of a cluster of
stars that has evaporated over time, becoming gravitationally unbound. Alternatively, the Hercules stream may have been created as a resonant effect of the galactic bar
Barred spiral galaxy
A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in approximately two-thirds of all spiral galaxies...
at the center of the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
. This stream
of stars has a space velocity component V equal to about −40 km/s.