Alicante 8, also known as RSGC4, (''Red Supergiant Cluster 4'') is a young massive

open cluster An open cluster is a type of star cluster made of up 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, an ...

belonging to the

Milky Way The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye. ...

galaxy. It was discovered in 2010 in the

2MASS The Two Micron All-Sky Survey, or 2MASS, was an astronomical survey of the whole sky in infrared light. It took place between 1997 and 2001, in two different locations: at the U.S. Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona, and ...

survey data. As of 2010, the only members of the cluster that are currently identified are 8–13

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

s—young massive stars undergoing

helium burning The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon. Triple-alpha process in stars Helium accumulates in the cores of stars as a result of the proton–pr ...

in their cores. The cluster is located in the constellation

Scutum The ''scutum'' (; plural ''scuta'') was a type of shield used among Italic peoples in antiquity, most notably by the army of ancient Rome starting about the fourth century BC. The Romans adopted it when they switched from the military formati ...

at the distance of about from the Sun. It is likely situated at the intersection of the northern end of the Long Bar of the Milky Way and the inner portion of the

Scutum–Centaurus Arm The Scutum–Centaurus Arm, also known as Scutum-Crux arm, is a long, diffuse curving streamer of stars, gas and dust that spirals outward from the proximate end of the Milky Way's central bar. The Milky Way has been posited since the 1950s to ...

—one of the two major spiral arms. The age of Alicante 8 is estimated to be around 16–20 million years. The observed red supergiants are

type II supernova A Type II supernova (plural: ''supernovae'' or ''supernovas'') results from the rapid collapse and violent explosion of a massive star. A star must have at least 8 times, but no more than 40 to 50 times, the mass of the Sun () to undergo th ...

progenitors. The cluster is heavily obscured and have not been detected in the

visible light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

. It lies close to other groupings of red supergiants known as

RSGC1 RSGC1 (''Red Supergiant Cluster 1'') is a young massive open cluster in the Milky Way galaxy. It was discovered in 2006 in the data generated by several infrared surveys, named for the unprecedented number of red supergiant members. The cluster ...

Stephenson 2 Stephenson 2 , also known as RSGC2 (''Red Supergiant Cluster 2''), is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 1990 as a cluster of red supergiants in a photographic, deep infrared survey by the astrono ...

RSGC3 RSGC3 (''Red Supergiant Cluster 3'') is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 2010 in the GLIMPSE survey data. The cluster is located in the constellation Scutum at the distance of about 7 kp ...

Alicante 7 Alicante 7, also known as RSGC5, (''Red Supergiant Cluster 5'') is an open cluster rich in red supergiants found in the Scutum-Crux Arm of the Milky Way Galaxy, along with RSGC1, Stephenson 2, RSGC3, Alicante 8, and Alicante 10 Alicante 10 ...

, and

Alicante 10 Alicante 10, also known as RSGC6 (''Red Supergiant Cluster 6''), is a young massive open cluster belonging to the Milky Way galaxy. It was discovered in 2012 in the 2MASS survey data. Currently, eight red supergiants have been identified in thi ...

. The mass of the open cluster is estimated at 10–20 thousand solar masses, which makes it one of the most massive open clusters in the Galaxy.

References

{{DEFAULTSORT:Alicante 8 Alicante 8 Scutum (constellation) Scutum–Centaurus Arm