Pismis 20 is a compact open cluster in Circinus. It is located at the heart of the Circinus OB1 association in the Norma Arm of the Milky Way Galaxy.[2] Pismis 20 is about 3,270 pc away and only about 5 million years old. HD 134959, a blue supergiant variable star also called CX Circinus, is the brightest star in Pismis 20.[3]
Prominent stars
| Star name |
MV number |
Effective temperature |
Absolute magnitude |
Bolometric magnitude |
Mass (M☉) |
Spectral type |
Ref. |
|---|
| WR 67 |
11 |
56000 |
-4.03 |
-8 |
9 |
WN6-w |
[4] |
| CX Circinus (HD 134959) |
1 |
20900 |
-7.9 |
-9.8 |
50 |
B2.5Ia |
[5] |
|
6 |
42600 |
-4.2 |
-8.2 |
34 |
B |
[5] |
|
2 |
34400 |
-5.4 |
-8.8 |
34 |
O8.5I |
[5] |
|
3 |
28800 |
-5.5 |
-8.4 |
26 |
B0I |
[5] |
|
7 |
30200 |
-5 |
-8 |
23 |
B0III |
[5] |
|
4 |
29500 |
-5 |
-7.9 |
23 |
B0.2III |
[5] |
|
5 |
30200 |
-4.5 |
-7.5 |
20 |
B0III |
[5] |
|
References
- 1 2 "Pismis 20". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 December 2020.
- ↑ Turner, David G. (1996). "PISMIS 20 - A Case Study of a Young Cluster". Astronomical Journal. 111: 828. Bibcode:1996AJ....111..828T. doi:10.1086/117829.
- ↑ Orsatti, A. M.; Vega, E. I.; Marraco, H. G. (2003). "Pismis 20: One or two clusters?". Astronomy and Astrophysics. 408: 135–140. Bibcode:2003A&A...408..135O. doi:10.1051/0004-6361:20030919. hdl:11336/36974 – via 2003A&A...408..135O.
- ↑ Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J.; Oskinova, L. M. (2019). "The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters". Astronomy & Astrophysics. A57: 625. arXiv:1904.04687. Bibcode:2019A&A...625A..57H. doi:10.1051/0004-6361/201834850. S2CID 104292503.
- 1 2 3 4 5 6 7 Massey, P.; Degioia-Eastwood, K.; Waterhouse, E. (2001). "The Progenitor Masses of Wolf-Rayet Stars and Luminous Blue Variables Determined from Cluster Turnoffs. II. Results from 12 Galactic Clusters and OB Associations". The Astronomical Journal. 121 (2): 1050–1070. arXiv:astro-ph/0010654. Bibcode:2001AJ....121.1050M. doi:10.1086/318769. S2CID 53345173.
