NGC 1850 is a

double cluster The Double Cluster (also known as Caldwell 14) consists of the open clusters NGC 869 and NGC 884 (often designated h Persei and χ (chi) Persei, respectively), which are close together in the constellation Perseus. Both visible with the ...

and a

super star cluster A super star cluster (SSC) is a very massive young open cluster that is thought to be the precursor of a globular cluster. These clusters called "super" because they are relatively more luminous and contain more mass than other young star clusters. ...

in the

Dorado constellation Dorado () is a constellation in the southern sky. It was named in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish (''Coryphaena hippurus''), which is known as ''dorado'' in Spanish, althou ...

, located in the northwest part of the bar of the

Large Magellanic Cloud The Large Magellanic Cloud (LMC), or Nubecula Major, is a satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs (≈160,000 light-years), the LMC is the second- or third-closest galaxy to the Milky Way, after the ...

, at a distance of from the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. It was discovered by Scottish astronomer

James Dunlop James Dunlop FRSE (31 October 1793 – 22 September 1848) was a Scottish astronomer, noted for his work in Australia. He was employed by Sir Thomas Brisbane to work as astronomer's assistant at his private observatory, once located at Paramat ...

in 1826. This is an unusual cluster system because the main distribution of stars is like a

globular cluster A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of membe ...

, but unlike the globular clusters of 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 ...

it is composed of young stars. The only similar object in the Milky Way is

Westerlund 1 Westerlund 1 (abbreviated Wd1, sometimes called Ara Cluster) is a compact young super star cluster about 3.8 kpc (12,000 ly) away from Earth. It is thought to be the most massive young star cluster in the Milky Way, and was discovered by Ben ...

. The main cluster has the appearance of a globular cluster with an age of Myr. The second is a more loosely distributed sub-cluster with an age of Myr, located at an

angular separation Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in pa ...

of to the west of the main cluster. There are indications of interactions between the two, with the larger component being irregular and showing a tail toward the northwest. The main cluster is around 100 million years old, with a

tidal radius A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of membe ...

of 10

light year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s and an overall radius of 16 light years. It has an estimated mass of 42,000 times the

mass of the Sun 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 ...

. The stellar component is split into two

main sequence In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Her ...

populations, with about a quarter of the stars in a blue (hotter) group and the rest in a redder (cooler) population. The cluster is embedded in an ionization region designated Henize 103. The much younger subcluster, often designated NGC 1850A, contains a number of young, massive O/B-type stars that are on or near the

, distributed up to from the central clump. Seven subcluster members have masses of , and two of those are . Lower mass members up to are still on the

pre-main-sequence A pre-main-sequence star (also known as a PMS star and PMS object) is a star in the stage when it has not yet reached the main sequence. Earlier in its life, the object is a protostar that grows by acquiring mass from its surrounding envelope of ...

stage. The age distribution of the subcluster members indicate star formation has been active almost constantly since its formation. The eastern side of the cluster is more obscured and has fewer OB stars. In November 2021, astronomers using

MUSE In ancient Greek religion and mythology, the Muses ( grc, Μοῦσαι, Moûsai, el, Μούσες, Múses) are the inspirational goddesses of literature, science, and the arts. They were considered the source of the knowledge embodied in the ...

on the

Very Large Telescope The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each with a primary mirror 8.2 m across, ...

reported the discovery of a stellar-mass

black hole A black hole is a region of spacetime where gravitation, gravity is so strong that nothing, including light or other Electromagnetic radiation, electromagnetic waves, has enough energy to escape it. The theory of general relativity predicts t ...

in NGC 1850 by viewing its influence on the motion of a star in close proximity, the first direct dynamical detection of a black hole in a young massive cluster.

Gallery

File:NGC 1850.jpg,

ESO The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental research organisation made up of 16 member states for ground-based ast ...

image of NGC 1850 showing the stellar cluster and surrounding nebulosity

References

External links

* {{DEFAULTSORT:NGC 1850 Globular clusters Open clusters Large Magellanic Cloud Dorado

1850 Events January–June * April ** Pope Pius IX returns from exile to Rome. ** Stephen Foster's parlor ballad "Ah! May the Red Rose Live Alway" is published in the United States. * April 4 – Los Angeles is incorporated as a cit ...