Sharpless 2-170, also known by the common name the Little Rosette Nebula is an emission nebula in the constellation Cassiopeia.[5]
| Emission nebula | |
|---|---|
| H II region | |
 Sh2-170 as seen by the Hubble Space Telescope | |
| Observation data: epoch | |
| Right ascension | 00h 01m 29s |
| Declination | +64° 39' 03" |
| Distance | 7,500[1] ly |
| Apparent magnitude (V) | ~6.5 |
| Apparent dimensions (V) | 56' x 50'[2] |
| Constellation | Cassiopeia |
| Designations | LBN 577, Sh 2-170,[3] LBN 117.62+02.29 [4] |
It was discovered by Stewart Sharpless in the late 1950s, and its discovery published in 1959. It is named after the larger, much more well known Rosette Nebula.[4] It is located in the Perseus Arm of the Milky Way galaxy. Although being a separate nebula, it is considered as the dot in the Question Mark Nebula, as an extension of NGC 7822.
The nebula contains a central star cluster, Stock 18.[6] Stock 18, has an apparent size much smaller than the nebula's total of 56 x 50 arcminutes, with the cluster having an apparent size of just 18 arcminutes.[7] Some of its illumination is caused by the ionizing of gas by the star BD + 63 2093, also designated LS I +64 11.[8] There is dispute between studies as to the nature of said central star. A 1995 paper concluded the star was a O8 V type, however other papers have identified it as a O9 V type, and SIMBAD labels it as a G5 star.[9] The nebula contains a total of 71 variable stars.[10]
Visibility
editSh 2-170 has a magnitude of about 6.5. It is best viewed with a hydrogen-alpha filter. Most of the nebula is faint enough that it requires a longer exposure time to be visible to cameras.[11]
See also
edit- Rosette Nebula
- NGC 1624, the Little Cocoon Nebula
References
edit- ↑ "Sh2-170 - The Little Rosette Nebula". AAPOD2.COM. Retrieved 2025-09-08.
- ↑ "SH2-170". www.simg.de. Retrieved 2025-09-08.
- ↑ Cosgrove, Patrick A. (November 19, 2021). "SH2-170, The "Little Rosette" Nebula in SHO - 7 hours". Cosgrove's Cosmos. Retrieved 2025-09-08.
- 1 2 "Little Rosette Nebula (Sh 2-170) | Deep⋆Sky Corner". www.deepskycorner.ch. Retrieved 2025-09-08.
- ↑ "Sh2-170 · Baerenstein Observatory". Sternwarte Bärenstein. Retrieved 2025-09-08.
- ↑ Brecher, Ron (November 22, 2014). "Sh2-170 Emission Nebula". Astrodoc: Astrophotography by Ron Brecher. Retrieved 2025-09-08.
- ↑ Bhatt, Himali; Sagar, Ram; Pandey, J.C. (February 2012). "Stellar contents and star formation in the young cluster Stock 18". New Astronomy. 17 (2): 160–166. arXiv:1108.3407. Bibcode:2012NewA...17..160B. doi:10.1016/j.newast.2011.07.015.
- ↑ "Sh2-170 in Cassiopeia". www.irida-observatory.org. Retrieved 2025-09-08.
- ↑ "Sh 2-170". galaxymap.org. Retrieved 2025-09-08.
- ↑ Sinha, Tirthendu; Sharma, Saurabh; Pandey, A. K.; Yadav, R. K.; Ogura, K.; Matsunaga, N.; Kobayashi, N.; Bisht, P. S.; Pandey, R.; Ghosh, A. (2020). "Variable stars in the Sh 2-170 H ii region". Monthly Notices of the Royal Astronomical Society. 493: 267–287. arXiv:2001.08892. doi:10.1093/mnras/staa206.
- ↑ "SH2-170 (Sharpless 170)". www.sharplesscatalog.com. Retrieved 2025-09-08.