Sharpless 2-88

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Sharpless 2-88
Diffuse nebula
Observation data: Epoch J2000 epoch
Subtype Reflection/Emission[3]
Right ascension 19h 45m 59s[1]
Declination 25° 20' 00"[2]
Distance 6,523 ly   (2400 [4] pc)
Constellation Vulpecula
Physical characteristics
Absolute magnitude (V) --
Designations LBN 139, The Face of God Nebula
See also: Lists of nebulae

Sharpless 2-88, also known as Sh 2-88, is a region of diffuse nebulae northwest of the nebula knots Sh 2-88A, Sh 2-88B1, and Sh 2-88B2, which are all associated with Vulpecula OB1. This nebula is a HII type diffuse nebula excited by the type O8 star BD +26°3952.[5] Both neutral and ionized gases in Sh 2-88 are between 150 and 410 Msolar and the dust mass is about 2 to 9 Msolar. The nebula is ionized by an O8.5 to 9.5V star. The structure been interacting with a HI interstellar bubble shaped by the stellar winds of BD +26°3952 and the blue O8.5II(f) star BD +25°3866. Overall, its actual structure is located 2.4 kiloparsecs away, at 23 × 15 parsecs in radius, a dynamical age of 1.5 million years, and a mass of 1,300 Msolar. It has an rms electron density of 9 cm–3. All separate star forming regions are 1 minute in diameter.[6]

Nearby objects[edit]

(All of the nebulae mentioned are in the Vulpecula OB1 association.)

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 reigon 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 reigon ionized by a star that is dimmer than B0.5 V, and is ultracompact.[7]

HD 338916 is an emission line star that ionizes a close nebula in the Vulpecula OB1 association. It has an apparent magnitude (V) of 10.17 and a spectral type of O8 D.

HD 338926 is another emission line star that ionizes a close nebula in the Vulpecula OB1 association. It has an apparent magnitude (V) of 9.55 and a spectral type of O8e C.

References[edit]