Английская Википедия:IC 2391
Шаблон:Short description Шаблон:Infobox open cluster
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 Шаблон:Circa.[1][2] 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:[3]
| Name | Apparent magnitude (V) |
Spectral type | Distance (LY) |
|---|---|---|---|
| HD 74195 (ο Velorum) | 3.63 varies[4] | style="background:#Шаблон:Color temperature;"|B3/5(V)[5] | 496 ± 30.5[6] |
| HD 74560 (HY Velorum) sp. binary | 4.815[7] | style="background:#Шаблон:Color temperature;"| B3IV[5] | 490.4 ± 6.9[8] |
| HD 74146 (NZ Velorum) sp. binary | 5.19[9] | style="background:#Шаблон:Color temperature;"|B5IV[5] | 497.3 ± 7.5[10] |
| HD 74071 (HW Velorum) | 5.44[7] | style="background:#Шаблон:Color temperature;"|B5V[11] | 519.9 ± 7.5[12] |
| HD 74196 cepheid variable | 5.61[9] | style="background:#Шаблон:Color temperature;"|B9/A0[5] | 502 ± 4.1[13] |
| HD 74535 (KT Velorum) alpha2 CVn variable | 5.47[7] | style="background:#Шаблон:Color temperature;"|B9III(pSi)[5] | 421 ± 17.5[14] & radial velocity +14[15] so not a true member |
| HD 75466 | 6.27[7] | style="background:#Шаблон:Color temperature;"|B8V[5] | 479 ± 2.8[16] |
| HD 73952 | 6.43[7] | style="background:#Шаблон:Color temperature;"|B8V[5] | 483 ± 5.8[17] |
| HD 74438, youngest known quadruple star.[18][19][20] | 7.58[7] | style="background:#Шаблон:Color temperature;"|A2mA5-A8[5] | 472 ± 5.2[21] |
The stars' era of formation is similar to open cluster IC 2602 in neighbouring Carina,[22] and has a lithium depletion boundary age of about 50 million years.[23] The latter group averages about the same distance, placed at about 485 light years away.[24]
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.[25] The supposed association may chiefly comprise:[25]
| 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
External links
Шаблон:Sky
Шаблон:Caldwell catalogue
Шаблон:Vela (constellation)
- ↑ Deep-sky Observer's Handbook: Open and globular clusters, Kenneth Glyn Jones, Webb Society (1979), at p3
- ↑ The History of Astronomy, 2017, Anne Rooney, at p162
- ↑ Шаблон:Cite journal
- ↑ B.C. Reed, 'Catalog of galactic OB stars', Astronomy Journal, 125, 2531-2533 (2003/May-0)
- ↑ 5,0 5,1 5,2 5,3 5,4 5,5 5,6 5,7 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)
- ↑ Шаблон:Cite DR2
- ↑ 7,0 7,1 7,2 7,3 7,4 7,5 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)
- ↑ Шаблон:Cite DR3
- ↑ 9,0 9,1 Ducati, J.R., 'Catalogue of Stellar Photometry in Johnson's 11-color system', CDS/ADC Collection of Electronic Catalogues, 2237, 0 (2002)
- ↑ Шаблон:Cite DR3
- ↑ 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)
- ↑ Шаблон:Cite DR3
- ↑ Шаблон:Cite DR3
- ↑ Шаблон:Cite DR2
- ↑ 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)
- ↑ Шаблон:Cite DR3
- ↑ Шаблон:Cite DR3
- ↑ Шаблон:Cite journal
- ↑ Шаблон:Cite journal
- ↑ Шаблон:Cite web
- ↑ Шаблон:Cite DR3
- ↑ Шаблон:Cite journal
- ↑ Шаблон:Cite journal
- ↑ Шаблон:Cite DR3
- ↑ 25,0 25,1 Шаблон:Citation
