IC 2391
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 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.

It 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 along 50 arcminutes.

Visual and true members

It includes these members:[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[12] 519.9 ± 7.5[13]
HD 74196 cepheid variable 5.61[10] B9/A0[6] 502 ± 4.1[14]
HD 74535 (KT Velorum) alpha2 CVn variable 5.47[8] B9III(pSi)[6] 421 ± 17.5[15] & radial velocity +14[16] so not a true member
HD 75466 6.27[8] B8V[6] 479 ± 2.8[17]
HD 73952 6.43[8] B8V[6] 483 ± 5.8[18]
HD 74438, youngest known quadruple star.[19][20][21] 7.58[8] A2mA5-A8[6] 472 ± 5.2[22]

The stars' era of formation is similar to open cluster IC 2602 in neighbouring Carina,[23] and has a lithium depletion boundary age of about 50 million years.[24] The latter group averages about the same distance, placed at about 485 light years away.[25]

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.[26] The supposed association may chiefly comprise:[26]

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

See also

References

  1. ^ "IC 2391". sim-id. Retrieved 2020-06-11.
  2. ^ Deep-sky Observer's Handbook: Open and globular clusters, Kenneth Glyn Jones, Webb Society (1979), at p3
  3. ^ The History of Astronomy, 2017, Anne Rooney, at p162
  4. ^ 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.
  5. ^ B.C. Reed, 'Catalog of galactic OB stars', Astronomy Journal, 125, 2531-2533 (2003/May-0)
  6. ^ a b c d e f g h N. Houk, 'Catalogue of two-dimensional spectral types for the HD stars, Vol. 2', Michigan Spectral Survey##, Ann Arbor, Dep. Astron., University of Michigan, 2, 0 (1978)
  7. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  8. ^ a b c d e f Hog E., Fabricius, C., Makarov, V., Urban S., Corbin T., Wycoff, G, Bastian, U, Schwekendiek, P., Wicenec, A., 'The Tycho-2 catalogue of the 2.5 million brightest stars' Astronomy and Astrophysics, volume 355, L27-30 (2000/3-2)
  9. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  10. ^ a b Ducati, J.R., 'Catalogue of Stellar Photometry in Johnson's 11-color system', CDS/ADC Collection of Electronic Catalogues, 2237, 0 (2002)
  11. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  12. ^ Houk, N., Cowley A.P., 'Catalogue of two dimentional spectral types for the HD stars, Vol. 1', Michigan Spectral Survey, Ann Arbor, Dep. Astron., University of Michigan, 1, 0 (1975)
  13. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  14. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  15. ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  16. ^ Randich, S. & others, 'The Gaia-ESO Survey: open clusters in Gaia-DR1. A way forward to stellar age calibration.', Astronomy and Astrophysics, volume 612A, 99-99 (2018/4-1)
  17. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  18. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  19. ^ Merle, T. (December 2017). "The Gaia -ESO Survey: double-, triple-, and quadruple-line spectroscopic binary candidates". Astronomy & Astrophysics. 608: A95. arXiv:1707.01720. Bibcode:2017A&A...608A..95M. doi:10.1051/0004-6361/201730442. S2CID 119502806.
  20. ^ Platais, I.; Melo, C.; Mermilliod, J.-C.; Kozhurina-Platais, V.; Fulbright, J. P.; Méndez, R. A.; Altmann, M.; Sperauskas, J. (January 2007). "WIYN open cluster study: XXVI. Improved kinematic membership and spectroscopy of IC 2391". Astronomy & Astrophysics. 461 (2): 509–522. arXiv:astro-ph/0611584. Bibcode:2007A&A...461..509P. doi:10.1051/0004-6361:20065756. S2CID 17173564.
  21. ^ Plait, Phil (26 May 2022). "A weird four-star system may lead the way to catastrophic supernovae". SYFY Official Site. Archived from the original on 27 May 2022. Retrieved 4 June 2022.
  22. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  23. ^ 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.
  24. ^ 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. S2CID 208867491.
  25. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875.
  26. ^ a b 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

Wikimedia Commons has media related to IC 2391.


Caldwell catalogue
Constellation of Vela
Categories