Telescope Reviews: SH2-235 and a possible planetary

After Arp 157 I'm taking a short break from Arp galaxies to process a couple other things I took last winter. Here are Sharpless 2-235 and PK 173.7+02.7. The first is an emission nebula while the latter is a planetary nebula, at least it is so classified. They are located in the constellation of Auriga, just north of M36 so you know I took them some time ago and am just getting around to processing them. There's some major confusion as to the identities of these objects. There's some major confusion as to the identities of these objects. Even the normally accurate SIMBAD seems to have some problems here. Best I can determine SH2-235 is the large brilliant object that dominates the center of my image. The planetary is the orange object below it. However both SIMBAD and NED seem to think the planetary is SH2-235 and give the odd name of [KC97c] G173.6+02.8 to the Sharpless object. Yet Sharpless' description of 2-235 definitely identifies the big object as being the right one. The planetary is also identified in some catalogs as an HII emission nebula rather than a planetary. SIMBAD shows the location of the planetary as a molecular cloud full of masers which are microwave lasers often found in regions of star birth. This argues for the HII classification though the odd orange color is rare in HII regions but not unheard of. Also there are a lot of Herbig Haro objects in the area. Again these are new stars not dying ones that a planetary signifies. Looking for a Ph.D. thesis? Straightening this mess out might be one.

SH2-235 is considered to be caused by the collision of two vast molecular clouds. The collision has triggered a great amount of star formation that is only seen in deep dust penetrating infra red light. It is about 1800 parsecs (5900 light years) away by some estimates I found. It is part of a much larger complex consisting of several far larger Sharpless objects. All too big for my system. The faint H alpha seen in the upper left corner is a very small part of SH2-232. Even fainter tendrils from SH2-231 can be seen coming in from the right. They, along with SH2-233 way off to the right of my image are all part of the same complex. SH-2-235 is caused to glow by the brilliant 09 star near it core.

There's an asteroid in the image. It appears to be two lines on either side of a star just of the NE (upper left) edge of SH-235 as if I'm trying to point out the star. That's because I took 40 minutes of luminosity data, then 60 minutes of color data followed by 40 more minutes of luminosity and 30 more minutes of color data. Since the color data made a mess of the star's color it was subtracted out during processing. This makes the gap in the trail, which by coincidence jumped the star. The asteroid is (51850) 2001 OJ92 at magnitude 18.5.

Attached image at 1.5" per pixel, linked image at 1" per pixel

Full size image
http://www.spacebanter.com/attachment.php?attachmentid=2472&stc=1

14" LX200R @ f/10, L=8x10' binned 2x2 RGB=3x10' binned 3x3, STL=11000XM, Paramount ME

Edited to correct a typing error, I'd said SH2-234 rather than SH2-235 at one point in the text.

Rick

Edited by Rick J (06/10/09 01:44 AM)