Carina OB1 is a giant

OB association The Ob (; ) is a major river in Russia. It is in western Siberia, and with its tributary the Irtysh forms the world's seventh-longest river system, at . The Ob forms at the confluence of the Biya and Katun which have their origins in the Al ...

in the

Carina Nebula The Carina Nebula or Eta Carinae Nebula (catalogued as NGC 3372; also known as the Great Carina Nebula) is a large, complex area of bright and dark nebulosity in the constellation Carina, located in the Carina–Sagittarius Arm of the Milky W ...

, which is home to some of the most massive and luminous stars in the Milky Way Galaxy. It includes the young star clusters Collinder 228,

NGC 3293 NGC 3293 is an open cluster in the Carina constellation. It was discovered by Nicolas-Louis de Lacaille in 1751. It consists of more than 100 stars brighter than 14th magnitude in a 10 arc minute field, the brightest of which are blue supergian ...

NGC 3324 NGC 3324 is an open cluster in the southern constellation Carina (constellation), Carina, located northwest of the Carina Nebula at a distance of from Earth. It is closely associated with the emission nebula , also known as . The two are often ...

, IC 2581,

Trumpler 14 Trumpler 14 (''Tr 14'') is an open cluster with a diameter of , located within the inner regions of the Carina Nebula, approximately from Earth. Together with the nearby Trumpler 16, they are the main clusters of the Carina OB1 stellar associati ...

Trumpler 15 Trumpler 15 is an open cluster in the Carina (constellation), constellation Carina that lies on the outskirts of the Carina Nebula. Estimated ages of the stars in Trumpler 15 suggest that the cluster is slightly older than its sibling clusters T ...

and

Trumpler 16 Trumpler 16 (''Tr 16'') is a massive open cluster that is home to some of the most luminous stars in the Milky Way galaxy. It is situated within the Carina Nebula complex in the Carina–Sagittarius Arm, located approximately from Earth. The cl ...

, the last being the home of

Eta Carinae η Carinae (Eta Carinae, abbreviated to η Car), formerly known as η Argus, is a stellar system containing at least two stars with a combined luminosity greater than five million times that of the Sun, located around ...

. It also includes another massive and luminous star, HD 93129A. It is approximately from Earth. It is one of the largest known stellar associations, along with Sagittarius OB5 and

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 emb ...

. It is much easier to see than that of the other associations since Carina OB1 has relatively little dust extinction in its region. Together with Carina OB2, they compromise the most massive stellar grouping known in the galaxy. Carina OB1 is about across, and is the most massive stellar association in the Milky Way Galaxy since it lies within an active emission nebula. It contains many hot luminous stars which share common characteristics.

References

Carina Nebula Stellar associations Carina (constellation) {{star-cluster-stub