The Sharpless Catalog

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Sh 2-151

Coordinates: (108.58°, -2.75°)
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Five molecular clouds are part of the Sh 2-151 complex and have a total of 29 thousand solar masses. About 700 solar masses has been ionised by an unseen star that is likely obscured by dust in one of the molecular clouds.

A fuzzy but interesting image that shows the molecular cloud structure of Sh 2-151 can be seen in this MSX infrared image here. This image is very similar to the radio image shown in figure 2a of this 1998 paper.

Sh 2-152

Coordinates: (108.8°, -1.0°)
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The adjacent HII regions Sh 2-152 and Sh 2-153 appear to be physically related, with a major source of the ionising radiation being located in the brighter Sh 2-152 in an unnamed O9V star.

Avedisova combines Sh 2-152 and Sh 2-153 into the star formation region SFR 108.78-0.94, which also contains 7 masers including well studied ones such as V* V627 Cas and SH 2-152 SE. Sh 2-252 also contains the infrared cluster [BDS2003] 36.

Sh 2-152 and Sh 2-153 form one of the two cores of the 105 thousand solar mass molecular cloud [UUT2000] Cloud A. (The other core is associated with Sh 2-147, Sh 2-148, and Sh 2-149.) This molecular cloud may be interacting with the supernova remnant SNR G109.1-01.0 (CTB 109).

Sh 2-153

Coordinates: (108.8°, -1.0°)
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The adjacent HII regions Sh 2-152 and Sh 2-153 appear to be physically related with Sh 2-153 being the larger and fainter nebula in the image and a major source of the ionising radiation being located in the brighter Sh 2-152 in an unnamed O9V star.

Avedisova combines Sh 2-152 and Sh 2-153 into the star formation region SFR 108.78-0.94, which also contains 7 masers including well studied ones such as V* V627 Cas and SH 2-152 SE.

Sh 2-152 and Sh 2-153 form one of the two cores of the 105 thousand solar mass molecular cloud [UUT2000] Cloud A. (The other core is associated with Sh 2-147, Sh 2-148, and Sh 2-149.) This molecular cloud may be interacting with the supernova remnant SNR G109.1-01.0 (CTB 109).

Sh 2-154

Coordinates: (108.96°, 1.59°)
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Sh 2-154 is ionised by the B0 III giant LS III +60 28, according to Avedisova. She places the nebula in the star formation region SFR 108.96+1.59 along with a molecular cloud.

According to a 2000 paper, radiation from stars associated with Sh 2-154 may be accelerating a giant molecular cloud that appears to contain 700 solar masses of carbon monoxide and perhaps 10 thousand solar masses in total viral mass.

Sh 2-155

Coordinates: (110.15°, 2.61°)
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The Cave nebula interacts with the Cepheus B molecular cloud and is ionised by stars that belong to the Cep OB3 association.

Sharpless lists 9 potential ionising stars, including the B0 class HD 217086. SIMBAD says that this object is actually a O7 Vn class young stellar object with multiple components.

Avedisova places Sh 2-155 in the massive star formation region SFR 110.15+2.61 and lists 157 components, including 24 masers, 48 infrared sources and the dark nebulae LDN 1211 and LDN 1216.

You can read more about the history of star formation in this region in the Cep OB3 section of the description of the Brain and Bubble (120° - 110°) sector in the Commentary on the Galactic Plane.

A good image of this nebula can be found here. You can also view an interesting false colour MSX 8 μm infrared image of this region here.

Sh 2-156

Coordinates: (110.1°, 0.0°)
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Also called IC 1470, this HII region is part of the star cluster NGC 7510 according to Avedisova. It appears to be ionised by a single O7 class star.

The bright core is only one of five distinct and apparently independent emission sources within a giant molecular cloud.

Avedisova places Sh 2-156 in star formation region 110.12+0.04 with 35 components, including 7 masers, the reflection nebulae [SS62] 71 and PP 104 and the HII regions BFS 15 and BFS 16.

Russeil expands this star formation region and adds the HII regions BFS 14, BFS 17 and BFS 18 as well.

Sh 2-157

Coordinates: (111.29°, -0.66°)
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The northern portion of Sh 2-157 (Sim 13, sometimes known as Sh 2-157a) is a ring nebula around the Wolf-Rayet star WR 157, in the Basel 3 star cluster that is in turn part of the Cas OB2 association.

The southern portion of Sh 2-157 (Sim 14) may be ionised by stars not belonging to Basel 3.

Sh 2-157b is an ultracompact HII region visible within the more diffuse Sh 2-157a nebula.

Avedisova lists 4 additional ionising stars for Sh 2-157 (besides WR 157). These include the O7 I supergiant BD+59 2673.

The MSX infrared results reveal a very complex structure in this direction as can be seen in this image.

You can see a detailed false-colour visual light image here.

Sh 2-158

Coordinates: (111.5°, 0.8°)
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This is NGC 7538, a major star formation region in the Cas OB2 association. It is surrounded by the much larger diffuse nebula Sh 2-161B.

The main ionising star for this nebula is the O7 V star [WBN74] NGC 7538 IRS 6, but it includes several other O-stars as well.

Avedisova places Sh 2-158 in star formation region 111.54+0.82 with 101 components including 15 masers and the young stellar object NGC 7538 IRS 9.

Russeil combines Sh 2-158 and Sh 2-159 into one star formation region. You can see the two nebulae embedded in the 595 thousand solar mass dust cloud [UUT2000] Cloud G in this MSX infrared image.

Sh 2-159

Coordinates: (111.6°, 0.4°)
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Sh 2-159 appears to be ionised by the O9.5 class emission star [MO2001] 82.

Russeil combines Sh 2-158 and Sh 2-159 into one star formation region. You can see the two nebulae embedded in the 595 thousand solar mass dust cloud [UUT2000] Cloud G in this MSX infrared image.

All of these objects are part of the dusty Cas OB2 association.

A wide area image that includes Sh 2-159 can be seen here.

Sh 2-160

Coordinates: (111.93°, 4.08°)
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The HII region Sh 2-160 is located near or within the Cep OB3 association, which is part of the relatively nearby Cepheus molecular clouds, as can be seen on this face-on map.

Sharpless lists three possible ionising stars including the B0 III giant HD 218323, which Humphreys assigns to Cep OB3.

You can read more about the Cep OB3 association towards the bottom of the page describing the Brain and Bubble (120° - 110°) sector, which is part of the Commentary on the Galactic Plane.

You can see a good image by Mel Martin of this nebula here.

Navigate to nebula [ Previous | Next ]

Stewart Sharpless published the second and final version of his famous nebula catalog in 1959. Although astronomers publish articles referring to the Sharpless nebulae almost every month, there seems to be few places on the Internet that bring together information on these nebulae as a whole - unlike, for example, the Messier catalog. This is most likely because the Messier objects are visible to anyone with a pair of binoculars or a small telescope. Most of the Sharpless objects are clearly visible only in CCD images or in photographic plates taken by large telescopes. Fortunately some of these plates have now been digitally scanned and made publicly available.

Many of the brightest and most beautiful Milky Way star formation regions visible from the northern hemisphere are in the Sharpless catalog so the 313 objects it contains are well worth examining carefully. (In fact there are more than 313 objects as subsequent research has shown that some of the Sharpless nebulae consist of more than one object.) Although the Sharpless catalog is only intended to be complete for objects visible north of declination -27 degrees, a similar catalog covering the southern hemisphere was published by Alex Rodgers, Colin Campbell, and John Whiteoak in 1960, which is largely an expansion of Colin Gum's earlier catalog. You can visit a gallery of these RCW nebulae here. At least 50 objects in the Sharpless catalog are also in the RCW catalog and I have noted this in the descriptions of these objects.

Most of the images used to illustrate the Sharpless catalog were created using the POSS-II/UKSTU data of the Digitized Sky Survey, or, where available, the more detailed SuperCOSMOS Sky Survey. In both cases, green = UKST Infrared. Because green represents infrared, the images are not quite the same as would be seen at purely visual frequencies. Green in these images usually reveals warm dust or red giant stars.

These images were created using the POSS-II/UKSTU data of the Digitized Sky Survey and SuperCOSMOS using the process described here.

According to my correspondence with the Royal Observatory Edinburgh and the Space Telescope Science Institute, I am allowed to use the POSS-II/UKSTU data to create and display images for non-commercial purposes so long as I include this fine print for the SuperCOSMOS data:

Use of these images is courtesy of the UK Schmidt Telescope (copyright in which is owned by the Particle Physics and Astronomy Research Council of the UK and the Anglo-Australian Telescope Board) and the Southern Sky Survey as created by the SuperCOSMOS measuring machine and are reproduced here with permission from the Royal Observatory Edinburgh.

and this acknowledgement taken from the DSS site:

The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.

The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation.

The UK Schmidt Telescope was operated by the Royal Observatory Edinburgh, with funding from the UK Science and Engineering Research Council (later the UK Particle Physics and Astronomy Research Council), until 1988 June, and thereafter by the Anglo-Australian Observatory. The blue plates of the southern Sky Atlas and its Equatorial Extension (together known as the SERC-J), as well as the Equatorial Red (ER), and the Second Epoch [red] Survey (SES) were all taken with the UK Schmidt.

The "Second Epoch Survey" of the southern sky was made by the Anglo-Australian Observatory (AAO) with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright © 1993-5 by the Anglo-Australian Observatory Board, and are distributed herein by agreement.

The "Equatorial Red Atlas" of the southern sky was made with the UK Schmidt Telescope. Plates from this survey have been digitized and compressed by the ST ScI. The digitized images are copyright © 1992-5, jointly by the UK SERC/PPARC (Particle Physics and Astronomy Research Council, formerly Science and Engineering Research Council) and the Anglo-Australian Telescope Board, and are distributed herein by agreement.

The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright © 1993-1995 by the California Institute of Technology and are distributed herein by agreement. The compressed files of the "Palomar Observatory - Space Telescope Science Institute Digital Sky Survey" of the northern sky, based on scans of the Second Palomar Sky Survey are copyright © 1993-1995 by the California Institute of Technology and are distributed herein by agreement.