NGC 2194 is an

open cluster 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 the constellation

Orion Orion may refer to: Common meanings * Orion (constellation), named after the mythical hunter * Orion (mythology), a hunter in Greek mythology Arts and media Fictional entities Characters and species * Orion (character), a DC Comics c ...

. The cluster is located about 10,000

light year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...

s away from Earth. It is rich and moderately concentrated. The cluster lies 33 arcminutes west-northwest of 73 Orionis.

Observation history

It was discovered by

William Herschel Frederick William Herschel ( ; ; 15 November 1738 – 25 August 1822) was a German-British astronomer and composer. He frequently collaborated with his younger sister and fellow astronomer Caroline Herschel. Born in the Electorate of Hanover ...

on 11 February 1784, and it was added in his catalogue as IV 5. It was added to the General Catalogue as 1383. The cluster was also observed by

Adolph Cornelius Petersen Adolf (also spelt Adolph or Adolphe, Adolfo, and when Latinised Adolphus) is a given name with German origins. The name is a compound derived from the Old High German ''Athalwolf'' (or ''Hadulf''), a composition of ''athal'', or ''adal'', meani ...

in 1849 with the 18 cm refractor at the

Altona Observatory The Altona Observatory () was an astronomical observatory situated in the Palmaille, in Altona, Hamburg. The observatory was founded by Heinrich Christian Schumacher in 1823 and continued to operate until 1871, 21 years after his death. It clos ...

. The cluster was also observed by

Hermann Carl Vogel Hermann Carl Vogel (; ; 3 April 1841 – 13 August 1907) was a German astrophysicist. He was born in Leipzig, Kingdom of Saxony. From 1882 to 1907 he was director of the Astrophysical Observatory, Potsdam. He made extensive discoveries ...

, without mentioning its General Catalogue number.

John Louis Emil Dreyer John Louis Emil Dreyer (13 February 1852 – 14 September 1926), also Johan Ludvig Emil Dreyer, was a Danish astronomer who spent most of his career working in Ireland. He spent the last decade of his life in Oxford, England. Life Dreyer ...

added it to GCS as number 5380, as

Heinrich Louis d'Arrest Heinrich Louis d'Arrest (13 August 1822 – 14 June 1875; ) was a German astronomer, born in Berlin. His name is sometimes given as Heinrich Ludwig d'Arrest. Biography While still a student at the University of Berlin, d'Arrest was par ...

's discovery from 18 September 1862, without noticing it was already included.

Characteristics

NGC 2194 is a rich and moderately concentrated, with Trumpler class III1r, open cluster. The brightest stars of the cluster are of magnitude 10, the brightest being of magnitude 10.26. The cluster has 149 members down to 15th magnitude. The

main sequence In astronomy, the main sequence is a classification of stars which appear on plots of stellar color index, color versus absolute magnitude, brightness as a continuous and distinctive band. Stars on this band are known as main-sequence stars or d ...

turn off is at magnitude 14.5 and there are few

red giant A red giant is a luminous giant star of low or intermediate mass (roughly 0.3–8 solar masses ()) in a late phase of stellar evolution. The stellar atmosphere, outer atmosphere is inflated and tenuous, making the radius large and the surface t ...

s members. There are some stars that are bluer than the turn-off point and if they are members of the cluster they are possibly

blue straggler A blue straggler is a type of star that is more luminous and bluer than expected. Typically identified in a stellar cluster, they have a higher effective temperature than the main sequence turnoff point for the cluster, where ordinary stars b ...

s. The photometric study of the cluster by Sanner and al. concluded that the age of the cluster is 550 Myr and its distance is 2,900 pc. Piatti et al. determined the age of the cluster to be 400 Myr and its distance to be 3,200 pc. The cluster has low

metallicity In astronomy, metallicity is the Abundance of the chemical elements, abundance of Chemical element, elements present in an object that are heavier than hydrogen and helium. Most of the normal currently detectable (i.e. non-Dark matter, dark) matt ...

(−0.27 ± 0.06). It is located 130 pc south of the galactic plane. NGC 2194 DSS

References

External links

{{orion (constellation) 2194 Orion (constellation) Open clusters