IC 2391 (also known as the Omicron Velorum Cluster or Caldwell 85) 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 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 first constellati ...

Vela consisting of hot, young, blueish stars, some of which are binaries and one of which is a quadruple. Persian astronomer A. a.-R. al-Sufi first described it as "a nebulous star" in . It was re-found by

Abbe Lacaille Abbé Nicolas-Louis de Lacaille (; 15 March 171321 March 1762), formerly sometimes spelled de la Caille, was a kingdom of France, French astronomer and geodesist who named 14 out of the IAU designated constellations, 88 constellations. From 1750 ...

and cataloged as Lac II 5.

Description

IC 2391 is centred about 490

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

s away from

Earth Earth is the third planet from the Sun and the only astronomical object known to Planetary habitability, harbor life. This is enabled by Earth being an ocean world, the only one in the Solar System sustaining liquid surface water. Almost all ...

and can be seen with the

naked eye Naked eye, also called bare eye or unaided eye, is the practice of engaging in visual perception unaided by a magnification, magnifying, Optical telescope#Light-gathering power, light-collecting optical instrument, such as a telescope or microsc ...

. It contains about 30 stars with a total

visual magnitude Apparent magnitude () is a measure of the brightness of a star, astronomical object or other celestial objects like artificial satellites. Its value depends on its intrinsic luminosity, its distance, and any extinction of the object's light ca ...

of 2.5, spread out across 50 arcminutes.

Member stars

These are some of the prominent members of IC 2391: The stars' era of formation is similar to open cluster

IC 2602 IC 2602 (also known as the Southern Pleiades, Theta Carinae Cluster, or Caldwell 102) is an open cluster in the constellation Carina (constellation), Carina. Discovered by Abbe Lacaille in 1751 from South Africa, the cluster is easily visible to t ...

in neighbouring Carina, and has a

lithium depletion boundary Lithium (from , , ) is a chemical element; it has chemical symbol, symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard temperature and pressure, standard conditions, it is the least dense metal and the ...

age of about 50 million years. The latter group averages about the same distance, placed at about 485 light years away. O Velorum Cluster iTelescope

Argus Association

The components formed at about the same time as a nearer group, known as the "Argus Association" which one motion model suggests began in their own nebula cloud. These are in a similar direction, roughly the Vela constellation, within the local galactic arm. The supposed association may chiefly comprise:

References

External links

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2391 In contemporary history, the third millennium is the current millennium in the ''Anno Domini'' or Common Era, under the Gregorian calendar. It began on 1 January 2001 ( MMI) and will end on 31 December 3000 ( MMM), spanning the 21st to 30t ...

Open clusters Vela (constellation) 085b 64 64 {{Vela (constellation)

Description

Member stars

Argus Association

See also

References

External links