| 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, SH2-170, [3] LBN 117.62+02.29 [4] |
Sharpless 2-170, Also known by the common name the Little Rosette Nebula is an emission nebula in the constellation Cassiopeia [5] .
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. 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]
