Cygnus-X is a massive

star formation Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

region located in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

of Cygnus at a distance from the Sun of 1.4 kilo parsecs (4,600 light years). As it is located behind the Cygnus Rift and its light is heavily absorbed by 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 ...

interstellar dust Cosmic dust, also called extraterrestrial dust, star dust or space dust, is dust which exists in outer space, or has fallen on Earth. Most cosmic dust particles measure between a few molecules and 0.1 mm (100 micrometers). Larger particles are c ...

, it is better studied in other

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...

s of the

electromagnetic spectrum The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies. The electromagnetic spectrum covers electromagnetic waves with frequencies ranging from ...

that penetrate it such as the

infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...

Physical properties

As studies done with the help of the

Spitzer Space Telescope The Spitzer Space Telescope, formerly the Space Infrared Telescope Facility (SIRTF), was an infrared space telescope launched in 2003. Operations ended on 30 January 2020. Spitzer was the third space telescope dedicated to infrared astronomy, f ...

have shown, Cygnus-X has a size of 200 parsecs and contains the largest number of massive protostars as well as the largest

stellar association A stellar association is a very loose star cluster, looser than both open clusters and globular clusters. Stellar associations will normally contain from 10 to 100 or more stars. The stars share a common origin, but have become gravitationally u ...

(

Cygnus OB2 Cygnus OB2 is an OB association that is home to some of the most massive and most luminous stars known, including suspected Luminous blue variable Cyg OB2 #12. It also includes one of the largest known stars, NML Cygni. The region is em ...

, with up to 2,600 stars of spectral type OB and a mass of up to 10⁵

solar mass The solar mass () is a standard unit of mass in astronomy, equal to approximately . It is often used to indicate the masses of other stars, as well as stellar clusters, nebulae, galaxies and black holes. It is approximately equal to the mass ...

es) within a radius of 2 kiloparsecs of the Sun. It is also associated with one of the largest molecular clouds known, with a mass of 3 million solar masses. Its stellar population includes a large number of early-type stars as well as evolved massive stars such as

luminous blue variable Luminous blue variables (LBVs) are massive evolved stars that show unpredictable and sometimes dramatic variations in their spectra and brightness. They are also known as S Doradus variables after S Doradus, one of the brightest stars of the Larg ...

candidates,

Wolf–Rayet star Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. The spectra indicate very high surface ...

s, and supergiant stars of spectral types O and B. Ongoing research has shown Cygnus X includes two stellar associations: Cygnus OB2 and

Cygnus OB9 Cygnus OB9 is an OB association in Cygnus. It is near to the Cygnus OB2 association. The region is embedded within a wider one of star formation known as Cygnus X, which is one of the most luminous objects in the sky at radio wavelengths. The r ...

as well as an additional large number of early-type stars that include

BD+40°4210 BD+40°4210 is a hot luminous giant star located in the constellation Cygnus. It is a member of the Cygnus OB2 association and a candidate luminous blue variable. Features BD+40°4210 is heavily reddened and extinguished by the inter ...

, a

blue supergiant star A blue supergiant (BSG) is a hot, luminous star, often referred to as an OB supergiant. They have luminosity class I and spectral class B9 or earlier. Blue supergiants are found towards the top left of the Hertzsprung–Russell diagram, above an ...

and luminous blue variable candidate that is one of the brightest stars of the association, as well as more supergiant stars of spectral types O and B. The same study shows that star formation has been taking place there during at least 10 million years, continuing to the present day.

References

What is the Cygnus-X Region?

* ttps://www.aanda.org/articles/aa/full_html/2012/07/aa19022-12/T3.html New members of the massive stellar population in Cygnus{{Cygnus (constellation) Emission nebulae Cygnus (constellation) Star-forming regions Molecular clouds

Physical properties

See also

References