| Diffuse nebula | |
|---|---|
 Sh2-88 Nebula from the Mount Lemmon SkyCenter Schulman Telescope | |
| Observation data:Epoch J2000epoch | |
| Subtype | Reflection/Emission[2] |
| Right ascension | 19h 45m 59s[1] |
| Declination | 25° 20' 00"[1] |
| Distance | 6,523 ly (2400[3] pc) |
| Apparent dimensions (V) | 47 light years across |
| Constellation | Vulpecula |
| Physical characteristics | |
| Radius | 345 ly |
| Absolute magnitude (V) | -- |
| Designations | LBN 139, The Face of God Nebula |
| See also:Lists of nebulae | |
Sharpless 2-88 orSh 2-88 is a region including thediffuse nebula Sh 2-88A and the two compactknots Sh 2-88B1 and Sh 2-88B2, all of which are associated withVulpecula OB1.
Sh 2-88A is anHII-type diffuse nebula excited by the typeO8 star BD+25°3952.[4] Both neutral and ionized gases in Sh 2-88 are between 150 and 410solar masses and the dust mass is about 2 to 9 solar masses. The structure has been interacting with a HI interstellar bubble shaped by the stellar winds of BD+25°3952 and the blue O8.5II(f) star BD +25°3866. Overall, its actual structure is located 2.4kiloparsecs away, at 23 × 15 parsecs in radius. It has a dynamical age of 1.5 million years, and a mass of 1,300 solar masses. It has anrms electron density of 9 cm−3. All separate star forming regions are 1arcminute in diameter.[5]
Sharpless 2-88 is the first part of this nebula to have created a star-forming region. It had star formation first start in this large diffuse nebula, which then spread to the other star-forming regions in the nebula. It spread to the compact Sharpless 2-88B1, then to the ultracompact Sharpless 2-88B2.
Sharpless 2-88B1 is a HII region ionized by an O8.5-9.5 V star, and is compact. It is also associated with a nearby star cluster that contains several massive stars.
Sharpless 2-88B2 is a HII region ionized by a star that is dimmer than B0.5 V, and is ultracompact.[6]
