The Scutum–Centaurus Arm, also known as Scutum-Crux arm, is a long, diffuse curving streamer of

star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked eye at night sk ...

s, gas and dust that spirals outward from the proximate end of the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

's central bar. The Milky Way has been posited since the 1950s to have four

spiral arm Spiral arms are a defining feature of spiral galaxies. They manifest as spiral-shaped regions of enhanced brightness within the galactic disc. Typically, spiral galaxies exhibit two or more spiral arms. The collective configuration of these arms i ...

s; numerous studies contest or nuance this number. In 2008, observations using the Spitzer Space Telescope failed to show the expected density of red clump giants in the direction of the Sagittarius and Norma arms. In January 2014, a 12-year study into the distribution and lifespan of massive stars and a 2013-reporting study of the distribution of masers and open clusters both found corroboratory, though would not state irrefutable, evidence for four principal spiral arms. The Scutum–Centaurus Arm lies between the minor Carina–Sagittarius Arm and the minor Norma Arm. The Scutum–Centaurus Arm starts near the core as the ''Scutum Arm'', then gradually turns into the ''Centaurus Arm''. The region where the Scutum–Centaurus Arm connects to the bar of the galaxy is rich in

star-forming region Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"— collapse and form stars. As a branch of astronomy, star formation inclu ...

s and

open clusters An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...

. In 2006 a large cluster of new stars containing 14

red supergiant Red supergiants (RSGs) are stars with a supergiant luminosity class ( Yerkes class I) and a stellar classification K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive or luminous. Betelg ...

stars was discovered there and named RSGC1. In 2007 a cluster of approximately 50,000 newly formed stars named RSGC2 was located only a few hundred light years from RSGC1. It is thought to be less than 20 million years old and contains 26 red supergiant stars, the largest grouping of such stars known. Other clusters in this region include RSGC3 and Alicante 8.

References

{{DEFAULTSORT:Scutum-Centaurus Arm Milky Way arms Galactic astronomy Spiral galaxies

See also

References