| Emission nebula | |
|---|---|
 | |
| Observation data: J2000.0epoch | |
| Right ascension | 07h 05m 13.0s |
| Declination | -12° 19′ 00″ |
| Distance | 3,300–4,600[1] ly |
| Constellation | Canis Major |
| Designations | Sh-297,LBN 1039, Ced 90[2] |
| See also:Lists of nebulae | |
Sh 2-297 (also known asSharpless 297) is an emission nebula in the constellationCanis Major.The region was catalogued in 1959 in the extended seconded edition of theSharpless catalogue.[3] This area is part of the Canis Major OB1Association, and is a very active area of newstar formation.[1]
Studies in 1988 found that the bright star illuminating the nebula was 8th magnitude HD 53623 / HIP 34178 with spectral class B1II/III.[4][1] Later in 2004 it was shown that there was embedded a cold but massiveYoung Stellar Object or YSO within Sh 2-297 near the edge of one of the dark rifts.[5] This object has been observed in the far-infrared, but it is so deeply embedded in aninterstellar cloud that it is undetectable in shorter wavelength observations such as theTwo Micron All Sky Survey (2MASS), leading it to be originally named "Unidentified young stellar object 1" or UYSO-1.[6] It was further revealed that this unseen stellar source produces acarbon monoxide (CO)bipolar outflow with a total mass of 5.4 M☉ solar masses, while the surrounding extended envelope weighs 30 M☉–40 M☉.[5][1] Some 96 other YSOs have been discovered to be part of Sh-297, having a mean age of one million years and range in masses between 0.3 M☉ and 2.0 M☉.[1] Manyvariable stars are also assigned with this nebula complex, including the three brightest: MW Ori, TT Ori and V559 Ori.
Distance is estimated between 1.0 and 1.4kpc. (3,300–4,600ly.),[1] averaging 1.2 kpc. or 3,900 ly.
This region was catalogued as part of the major clustering of reflection nebula asCMa R1 by van den Bergh in 1966.[7]Reflection nebulas were identified on blue plates of thePalomar Sky Survey, with positive confirmation made by checking nebulosity on the red plates. It was again later catalogued as LBN 1037 or LBN 225.27-02.42[8]
