Galactic Nebula MWC 137

MWC 137
MWC 137: B[e] Star with nebula; 500 mm Cassegrain f=3625mm / f7.2; SBIG STL11K; 50+3*25 min LRGB; Bernese Highlands; © 2011 Radek Chromik

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
MWC 137: Section of PanSTARRS DR1 [147]

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

Data for MWC 138 [145]
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.

Chart MWC 137
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

References

145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
146«Version 2000 of the Catalogue of Galactic Planetary Nebulae» L. Kohoutek, A&A Volume 378, Number 3, November II 2001; DOI:10.1051/0004-6361:20011162
147Aladin Lite; aladin.u-strasbg.fr/AladinLite (2020-12-23)
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
310«A Catalogue of H II Regions» Stewart Sharpless, US Naval Observatory, 1959; DOI:10.1086/190049; Bibcode:1959ApJS....4..257S
388«Catalogue and Bibliography of Stars of Classes B and A whose Spectra have Bright Hydrogen Lines» Merrill, Paul W.; Burwell, Cora G.; Astrophysical Journal, vol. 78, p.87, September 1933; DOI:10.1086/143490
389«Resolving the Circumstellar Environment of the Galactic B[e] Supergiant Star MWC 137 from Large to Small Scales» Michaela Kraus, Tiina Liimets, Cristina E. Cappa, Lydia S. Cidale, Dieter H. Nickeler, Nicolas U. Duronea, Maria L. Arias, Diah S. Gunawan, Mary E. Oksala, Marcelo Borges Fernandes, Grigoris Maravelias, Michel Curé, and Miguel Santander-García; Published 2017 October 20; The Astronomical Journal, Volume 154, Number 5; DOI:10.3847/1538-3881/aa8df6