IC 2391

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IC 2391
IC 2391 in Vele.jpg
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
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. The Persian astronomer Al Sufi may have first described it about 964. It was found by Abbe Lacaille and cataloged as Lac II 5.

The cluster is about 500 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 along 50 arcminutes. It includes the following naked-eye members:[2]

IC 2391 appears to be about the same age as the open cluster IC 2602,[3] and has a lithium depletion boundary age of about 50 million years.[4] IC 2391 has been closely linked to the Argus Association of co-moving stars. Proposed members of this moving group include Denebola, Epsilon Pavonis, 49 Ceti, HD 61005, and HD 88955.[5]

See also[edit]


  1. ^ "IC 2391". sim-id. Retrieved 2020-06-11.
  2. ^ Platais, I; Melo, C; Mermilliod, J. -C; Kozhurina-Platais, V; Fulbright, J. P; Méndez, R. A; Altmann, M; Sperauskas, J (2007). "WIYN open cluster study. XXVI. Improved kinematic membership and spectroscopy of IC 2391". Astronomy and Astrophysics. 461 (2): 509. arXiv:astro-ph/0611584. Bibcode:2007A&A...461..509P. doi:10.1051/0004-6361:20065756. S2CID 17173564.
  3. ^ Stauffer, J.R.; et al. (1997). "Rotational Velocities and Chromospheric/Coronal Activity of Low-Mass Stars in the Young Open Clusters IC 2391 and IC 2602". Astrophysical Journal. 479 (2): 776–791. Bibcode:1997ApJ...479..776S. doi:10.1086/303930.
  4. ^ Navascues, David Barrado y; Stauffer, John R.; Jayawardhana, Ray (2004-10-10). "Spectroscopy of Very Low Mass Stars and Brown Dwarfs in IC 2391: Lithium Depletion and Hα Emission". The Astrophysical Journal. 614 (1): 386–397. arXiv:astro-ph/0406436. Bibcode:2004ApJ...614..386B. doi:10.1086/423485. ISSN 0004-637X.
  5. ^ Malo, Lison; et al. (January 2013), "Bayesian Analysis to Identify New Star Candidates in Nearby Young Stellar Kinematic Groups", The Astrophysical Journal, 762 (2): 50, arXiv:1209.2077, Bibcode:2013ApJ...762...88M, doi:10.1088/0004-637X/762/2/88, S2CID 118497872, 88.

External links[edit]

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