Coordinates: Sky map 08h 40m 18s, −52° 54′ 60″

IC 2391

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IC 2391
File:IC 2391 DSS.png
Observation data (J2000.0 epoch)
Right ascension08h 40.6m
Declination−53° 02′
Distance574 ly (176 pc[1])
Apparent magnitude (V)2.5
Apparent dimensions (V)50′
Physical characteristics
Other designationsCaldwell 85, Cr 191, C 0838-528, Lac II 5
Associations
ConstellationVela
See also: Open cluster, List of open clusters

IC 2391 (also known as the Omicron Velorum Cluster or Caldwell 85) is an open cluster in the constellation 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 c. 964.[2][3] It was re-found by Abbe Lacaille and cataloged as Lac II 5.

Description

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IC 2391 is centred about 490 light-years away from Earth and can be seen with the naked eye. It contains about 30 stars with a total visual magnitude of 2.5, spread out across 50 arcminutes.

Member stars

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These are some of the prominent members of IC 2391:[4]

Name Apparent
magnitude (V)		 Spectral type Distance (LY)
HD 74195 (ο Velorum) 3.63 varies[5] B3/5(V)[6] 496±30.5[7]
HD 74560 (HY Velorum) sp. binary 4.815[8] B3IV[6] 490.4±6.9[9]
HD 74146 (NZ Velorum) sp. binary 5.19[10] B5IV[6] 497.3±7.5[11]
HD 74071 (HW Velorum) 5.44[8] B5V[6] 519.9±7.5[12]
HD 74196 cepheid variable 5.61[10] B9/A0[6] 502±4.1[13]
HD 74535 (KT Velorum) alpha2 CVn variable 5.47[8] B9III(pSi)[6] 421±17.5[14]
HD 75466 6.27[8] B8V[6] 479±2.8[15]
HD 73952 6.43[8] B8V[6] 483±5.8[16]
HD 74438, youngest known quadruple star.[17][18][19] 7.58[8] A2mA5-A8[6] 472±5.2[20]

The stars' era of formation is similar to open cluster IC 2602 in neighbouring Carina,[21] and has a lithium depletion boundary age of about 50 million years.[22] The latter group averages about the same distance, placed at about 485 light years away.[23]

File:O Velorum Cluster iTelescope.png
A close of image of IC 2391. Credits: iTelescope.net (T59)

Argus Association

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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.[24] The supposed association may chiefly comprise:[24]

Name Constellation Distance Radial velocity
Epsilon Pavonis Pavo 105 −6.7
HD 88955 Vela 100 +7.4
HD 61005 Puppis 119 +22

References

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  6. ^ a b c d e f g h i Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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  8. ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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  10. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  11. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR3 record for this source at VizieR.
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  14. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR2 record for this source at VizieR.
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  20. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR3 record for this source at VizieR.
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  24. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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Wikimedia Commons has media related to [[commons:Lua error in Module:WikidataIB at line 506: attempt to index field 'wikibase' (a nil value).|Lua error in Module:WikidataIB at line 506: attempt to index field 'wikibase' (a nil value).]].
  • Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  • IC 2391 on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
  • Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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