| Description | Images | SH2-165Sh2-165 AKA LBN 565 is a rather faint emission nebula Cassiopeia 1.75 degrees east of M52. It is likely part of the Cas OB5 supershell. I found three different distance measurements: 1.6±.5kpc, 1.9±.4kpc and simply 1.7kpc. In light-years that's 5,200±1,600; 6,200±1,300 and 5,500 light-years respectively. So say between 5000 and 6000 light years wouldn't be too far off. Distances to such objects is not easy to determine. It's surprising three different methods agreed so well. The one reference to its illuminating star says it is a B0.5V star but didn't give a position. I assume it is the bright one at the core but sometimes this isn't correct. While it is blue it doesn't seem as blue as I'd expect for a main sequence early B giant star. |
| SH2-168Sh2-168 is a spherical cloud of ionized Hydrogen that is about 9.5 light-years across. It is also known as LBN568. It thought to be about 11600 light-years distant and is located in Cassiopeia to the northwest of Caph, the northwest star of the "W". The faint nebula to the southeast is Sh2-169. The two are likely part of the same cloud. |
| SH2-170Sh-170 is an emission nebula in the northwestern corner of Cassiopeia not far south of Sh-171 on the Cepheus-Cassiopeia border. It is a round emission nebula with the open cluster Stock 18 at its center. Toward the left of the somewhat dark center is BD+63 2093p which is an 08V or 09V star. Galaxy Map says it has a mass 31 times that of the sun. There seems to be some disagreement. It is considered the illuminating star for the nebula. One distance measurement I found puts it 7500 light-years distant. The visible part of the cloud is thought to have a mass of about 900 suns give or take 10%. |
| SH2-171Sh2-171 (see also NGC 7822) is a star-forming region in Cepheus. It is also known as Ced 214. It is far larger than my field so I've just picked a part of it including the star cluster Berkeley 59. APOD puts it at about 3000 light-years from us. Most images you see of this object are done using narrowband filters and the Hubble palette (SHO) in which SII (sulfur) is mapped to red, H alpha (Hydrogen) is mapped to green and OIII (oxygen) is assigned blue. I've used LRGB with some H alpha added since it is the prominent component of the nebula. I've tried to balance the colors to show what the eye would see if it were equally sensitive to all colors. In fact, the eye is most sensitive to green so the nebula would appear somewhat green to the eye if it were bright enough to register on our cones that see color. It is too faint to do this even in very large scopes so appears just as a faint gray smudge with the stars of Berkeley 59 dominating. |
| SH2-175SH2-175 aka LBN 596 is an emission nebula around LS I +64 26. Some sources say it is an O9.5 V star while others say it is a B1.5 V star. Not a big difference but still surprising. Less surprising is the uncertainty about the distance to this star and thus the nebula. I find estimates of 5100, 5550, and 6000 light-years by those saying it is a 09.5 V star. Russeil (yes, that is spelled correctly), who says it is really a B1.5 V star puts it at 3500 +/- 330 light-years. I assume the fact a B1.5 V star is a bit fainter than a 09.5 V star accounts for some if not most of the distance difference. All seem to agree that while it is seen in the area of the Cassiopeia OB1 complex it lies considerably closer to us and thus isn't part of the complex which is often said to be about 8200 light-years distant. |
| SH2-187SH2-187 reminds me of an angry wolf spider about to bite. No legs, just big, wide open fangs seen face on. I really need to retake this one at a larger image scale, I used 3x3 binning probably to reduce exposure time as this is a very faint object. It is also known as LBN 630. The dark nebula around it is LDN 1317-18. Why it has both numbers I don't know. One distance estimate I found say it is about 4700 light-years distant and is on the outer edge of the Orion arm. The nebula is surrounded by a large cloud of neutral hydrogen with a mass of about 7600 suns. IR shows the nebula to hide a lot of newly formed stars. The nebula appears to have a strong reflection element to it, likely due to some of these stars. |
| SH2-188The next planetary SH2-188 looks much like the Medusa Nebula though you'll see no blue in it. But the real clue that something different is going on here is that the "white" dwarf is not in the center of the arc as it is in the Medusa Nebula. The arc is very close to the star. It is the faint blue star near the rather obvious orange star well down and left of center. Near the center, there is a bright blue star but that is not related to the nebula. So how did the central star get so far off of center? The best idea to date is that this is a runaway star. At one time it was a member of a binary star system. That star, long long ago, blew itself up nearly completely. It didn't leave a neutron star or black hole. The companion star was then flung into space by its orbital velocity much as letting David's sling release its stone. Now this rather normal star was hurtling through space. When this star eventually turned into a white dwarf and lets its outer shell puff off the shell immediately ran into the interstellar gases. While both are less dense than the best vacuum we can create in our labs there was almost immediately a collision but a very lopsided one as the gasses from the opposite side of the shell were running away from the interstellar gasses so no collision could occur to any extent. The bubble was free to expand unbothered by the dust and gas between stars to the upper right but toward the lower left, the direction the star was moving at high speed, the collision immediately slowed down the shell given off by the central star preventing it from getting very far away from its source. This very violent collision makes the red arcs you see. Notice the brightest parts of the nebula are at the point of collision. The central star in this nebula is just too weak to cause the gases to glow blue so none is seen. Note the odd stuff in the lower left corner are due to bright blue and yellow stars just off the edge of the CCD and aren't real objects, just ghosts created when a bright star hits the very edge of the glass protecting the CCD. Some are available without the glass and don't have this problem but mine isn't available without a cover so this happens every now and then. If you want some deep reading on the nature of this object and how it was formed go to: |
| SH2-212Sh2-212 also has an NGC number, 1624 though this referrs to the open cluster not the nebula. The NGC catalog lists it as being 6 or 7 stars involved in nebulosity. Sharpless recorded the HII region that is the referred to as SH2-212. Actually, it is a far more interesting and studied object than you might expect. It is thought to be about 6 thousand parsecs away (about 20 thousand light years) and helps define the Perseus arm of our galaxy. This nebula recently helped decide a major issue of star formation. When a nebula forms new stars in its core it starts to be disrupted by the effects of these stars. The question was whether star formation could happen in the regions at the outskirts where this dust and gas was being blown or would the area be disrupted too much to allow stars to form before the region became too chaotic for this to happen. It turns out stars are being formed and some have just been formed in the outer parts of this nebula by the collect and collapse method. The stars we see in the center of the nebula formed some 4 million years ago. Those formed at the edge are still mostly hidden by the dust and gas that surrounds them and fed their creation. Related Designations for SH2-212SH2-212, NGC1624, NGC 1624, 2MASX J04403475+5027419, 87GB 043647.6+502152, 87GB[BWE91] 0436+5021, [WB92] 0436+5021, NVSS J044036+502744, 6C B043646.6+502153, 7C 0436+5022, SHARPLESS 212, [KC97] G155.4+02.6, |
| SH2-219SH 2-219 also known as LBN747 is a small emission nebula in western Auriga showing you it was imaged months ago and I'm just getting it processed. While there's been a lot of study on this compact emission nebula associated with a larger unseen molecular cloud, the distance to it is rather vague. The best estimate is about 13700 light years plus or minus 2000 light years. Using the 13700 figure it would be about 12 light-years across. It is thought to be very young, maybe no more than 100,000 years since the stars causing it to glow were born. Deep infrared shows a star cluster embedded in its southwest corner. That area is bluer than the rest so may have some reflection component from this cluster though I see no sign of its stars at visual frequencies. The IR POSS2 plate shows some hint of it. Also, there is reported to be a 2000 solar mass molecular cloud nearby but no other information about it that I could find other than it is about 24 light years long. This image is taken looking at the heart of the winter Milky Way. It's gas and dust seem to be blocking all but a very few distant galaxies. I couldn't find but a very few and only saw them after blowing up the image considerably. |
| SH2-226SH2-226 is one I apparently never did publish. It needs H alpha data to bring it out. I can't find much, if anything on it. It is also known as LBN 780. I can't find a distance other than a mention it is likely beyond the Auriga OB1 association which itself is in the outer reaches of our galaxy. Maybe it was the lack of info that caused me not to ever publish it. |
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