Galactic Nebula MWC 137
History
The designation MWC 137 refers to the «Mount Wilson Catalog» [388] published in 1933, a catalog of class O, B and A stars with bright hydrogen lines. Stewart Sharpless recorded the nebula around the star V1308 Orionis under the designation Sh2-266 in his catalog of H-II regions published in 1959 and described it as elliptical, amorphous to fibrous and very bright. [310] The nebula was originally thought to be a planetary nebula in 1967 by the two Czech astronomers Luboš Perek and Luboš Kohoutek, which is why it was named PK 195-0.1. In the version from 2000 it is finally listed as an incorrectly classified PN. [146]
Physical Properties
MWC 137 belongs to the group of galactic B[e] stars, is surrounded by the nebula Sh2-266 and is located in the center of a star cluster at a distance of 5.2 ± 1.4 kpc. The age of this star cluster is estimated to be more than three million years. The evolutionary status of MWC 137 has been debated for a long time. Suggestions ranged from pre-main series to post-main series. With the discovery of a hot, circumstellar disc of CO emissions, a preliminary stage of the main series could be ruled out. With a mass of 10-15 solar masses, the star has moved far away from the main sequence. In 2016, a multi-node jet was discovered moving away from MWC 137 at high speed. Estimates of the age of these nodes indicated that they are much more recent than the large area nebula. The position angle of the jet is with the polarization angle and at right angles to the rotating, circumstellar disk. The large-area Hα structure could be a ring nebula that was created by the interaction of stellar winds with the interstellar medium, or it could also be a B[e] supergiant that changes to a blue supergiant with a bipolar ring. Research showed, however, that MWC 137 alone could not create the geometric structure of the nebula. [389]
Further infos at CDS: MWC 137
| Designations | MWC 138, V1308 Orionis, Sh2-266, PK 195-0.1 |
| ICRS Coordinates | 06h 18m 45.5s +15° 16' 52.2" |
| Type | Herbig Ae/Be Star |
| Spektral Type | sgB[e]d |
| Magnitudes | U 12.89, B 13.3, V 13.759, g 12.8, R 11.67, r 11.09, i 10.6, I 10.31, J 8.762, H 7.84, K 6.623 |
| Diameter | 1.117' |
Finder Chart
MWC 137 is located in the constellation Orion. The best time to observe is July to January, when the circumpolar constellation is highest.
