Astronomy:Sh 2-4
From HandWiki
| Emission nebula | |
|---|---|
| H II region | |
 As seen by the DESI Legacy Survey | |
| Observation data: epoch | |
| Right ascension | 17h 19m 48.5s |
| Declination | −39° 20′ 19″[1] |
| Distance | 8,800 ly (2,700 pc) |
| Apparent magnitude (V) | 14.95 [2] |
| Apparent dimensions (V) | 5' |
| Constellation | Scorpius |
| Designations | RCW 121, ESO 333-3, IRAS 17149-3916, Haro 3-6, PN H 2-6[3] |
Sh 2-4 is an emission nebula in the constellation Scorpius. It is part of the Sharpless Catalog assembled by Stewart Sharpless.[4] It was originally misidentified as a planetary nebula. The incorrect planetary designation PN H 2-6 can still be used as an identifier. It may be associated with the star cluster Havlen-Moffat 1.[1]
Visibility
The nebula is bright, and visible with longer exposure. The nebula mostly emits red light, making viewing through a hydrogen-alpha filter effective.[5]
Structure
Havlen-Moffat 1 is known to be a source of ionization within Sh 2-4. The nebula contains two Wolf-Rayet stars, designated WR 87 and WR 89.[6] Contained within the nebula is the infrared cluster [DBS2003] 118. [7]
References
- ↑ 1.0 1.1 "The Sharpless Observing Atlas". https://www.astromaster.org/oggetti/sharpless_data/Sharpless_r.pdf.
- ↑ "Sharpless (Sh2) - Astrobasics". 13 September 2022. https://astrobasics.de/galerie/kataloge/sh2/#object-10419.
- ↑ "RCW 121". https://simbad.u-strasbg.fr/simbad/sim-id?Ident=RCW+121&submit=submit+id.
- ↑ "CCD Images of the Sharpless Catalog". http://www.sharplesscatalog.com/sharplessdata.aspx.
- ↑ "SH2-4 (Sharpless 4)". http://www.sharplesscatalog.com/sharpless/SH2-4.aspx.
- ↑ "RCW 121". http://galaxymap.org/cat/view/rcw/121.
- ↑ Dutra, C. M.; Bica, E.; Soares, J.; Barbuy, B. (2003). "New infrared star clusters in the southern Milky Way with 2MASS". Astronomy and Astrophysics 400 (2): 533. doi:10.1051/0004-6361:20030005. Bibcode: 2003A&A...400..533D. https://ui.adsabs.harvard.edu/abs/2003A%26A...400..533D/abstract.
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