Although very little appears in the scientific literature on the mysterious HII region Sh 2-124, located some distance to the west of the Cep OB1 association, recent detailed hydrogen-alpha imaging done for the IPHAS project reveals the structure of this violin-shaped nebula in spectacular detail
Infrared imaging from MSX reveals a bubble
in this direction.
Felli and Harten give a list of 5 ionising stars, including the O7.5 class LS III +50 28
, and support the BFS distance estimate of 2600 parsecs. However, other sources argue that this star may be too cool to be the ionising star.
Chini and Wink identify two uncatalogued ionising stars, with classes O7V and B2V, and give a distance estimate of 3600 parsecs.
Crampton, Georgelin and Georgelin give a kinematic distance (based on gas velocity) of 4400 parsecs.
Felli and Harten give a list of 5 ionising stars, including the O7.5 class LS III +50 28, and support the BFS distance estimate of 2600 parsecs.[1
However, a 2011 paper states that LS III +50 28 may be too cool to be the ionising star for this nebula. [2
Gives a kinematic distance estimate of 4400 parsecs.[3
Identifies two ionising stars. Star 1 is O7V, star 2 is B2V. Distance estimate of 3600 parsecs.[4
This paper includes a radio image of Sh 2-124 as it is in the same field as the supernova remnant CTB 104A, which the paper is actually about. There is no further information about the nebula, however.[5
1. ^ Felli, M. & Harten, R. H. (1981). "A high-resolution search for
small-scale structure in Sharpless H II regions at 4.995 GHz. II - General
properties of the entire sample. III - Description of selected sources",
Astronomy and Astrophysics, Vol. 100, 28-58. [1981A&A...100...28F]
2. ^ Arvidsson, K. & Kerton, C. R. (2011). "Submillimeter and Molecular Views
of Three Galactic Ring-like H II Regions", The Astronomical Journal, Vol.
141, 153. [2011AJ....141..153A]
3. ^ Crampton, D., Georgelin, Y. M., & Georgelin, Y. P. (1978). "First optical
detection of W51 and observations of new H II regions and exciting stars",
Astronomy and Astrophysics, Vol. 66, 1-11. [1978A&A....66....1C]
4. ^ Chini, R. & Wink, J. E. (1984). "The galactic rotation outside the solar
circle", Astronomy and Astrophysics, Vol. 139, L5-L8.
5. ^ Uyaniker, Bülent, Kothes, Roland, & Brunt, Christopher M. (2002). "The
Supernova Remnant CTB 104A: Magnetic Field Structure and Interaction with
the Environment", The Astrophysical Journal, Vol. 565, 1022-1034.