Qualitative Dynamics of WR134 & Molecular Cloud - Starry
WR134 in SHO (Hubble Palette)
Askar 151phq; AP Mach2 GTO
ASI6200MM, - Chroma RGB & 5nm Narrowband Filters
H,O,S: (44,31,37 x 720s 61Bin 1, Gain 100)
R,G,B: (8,12,8 x 120s, Bin 1, Gain 100)
Total integration time = 23.3 hrs (July 9 to 13, 2024)
I believe that there is a heck of a lot going on and a lot to learn from in this, and other images of WR134, particularly when compared with images of other WR stars, such as the Crescent Nebula both of which are travelling relative to a nearby / surrounding molecular cloud.
Wolf Rayet stars, as far as my understanding goes, are larger dying stars that have not exactly gone super-nova or vanilla nova, but somewhere in between. When they begin to run out of concentrated hydrogen to fuse, they blow off much of their remaining lighter elements in a supernova-like explosion, but continue to fuse larger atoms under higher pressures and temperatures and emit intense UV radiation. The star does not die as white dwarf, neutron star, or black hole, but continues to burn, lighting up both the shells of material it has blown away, in addition to any material close by in molecular clouds. This is all very interesting and all, but is just background material to what happens when the Wolf Rayet star continues to move relative to a molecular cloud and relative to the background star.
In this image, I posit that the Wolf Rayet star,”WR134” and its shell of supersonically displaced oxygen shell are moving from right to left in the image, leaving a pattern that can be interpreted by a fluid dynamicist.
The O3 shell of the WR star appears to be forming a bow front to the left of the central WR star due to compression against the more stationary molecular cloud and is much brighter than the trailing edge to the right. But where is the lighter hydrogen material that must have been blown off when the star exploded? The image suggests that the some remains of this shell have been left to the right of current WR134 position, now forming a “ghost” to the central right of the image likely the position of WR134 when it exploded (best seen in starless version). Alternatively, this ghost may simply be a shadow cast by portions of the molecular cloud that has past the WR star.
Another observation is that [OIII] signal is largely confined to the left of the image. I don’t know if the oxygen outside the WR star originated from the star or was part of the molecular cloud that is in impact. It is likely that the oxygen is being ionized and lit up by the WR star’s UV emissions, however. The [OIII] signal seems to form a supersonic conical pattern pointing in the direction of travel of the WR134 against the molecular cloud.
In contrast, the Ha (in addition to the SII) signal, however, show features of viscous, subsonic turbulent flow around the WR star. This has the cool effect of making the WR star appear somewhat like a comet, with a trail of Ha eddies in the wake of the WR star. Note that gaseous hydrogen at the same pressure, will form a much less dense, lower viscosity material and carry far less momentum than material formed by higher atom number elements. This may account for the differences in the displacement and distribution of resultant signal.
I believe the Crescent Nebula’s asymmetry is similarly being caused by the movement of its WR star relative to interstellar material. However, the movement is much less pronounced and both its Ha and [OIII] emitting shells are still intact, only slightly warped by the movement.
