The RCW Catalog

Click on the small images to see larger ones.

Navigate to nebula [ Previous | Next ]

RCW 11

Coordinates: (234.76°, -10.09°)
[ See details ]

This ring nebula surrounds the Wolf-Rayet star WR 6 (EZ CMa), which is one of the closest Wolf-Rayet stars to our solar system and may also partially ionise Sh 2-303 and Sh 2-304.

This distance to WR 6 is a matter of some controversy. The Hipparcos astrometric satellite results were used in 1997 to determine a parallax suggesting a distance of about 575 parsecs. However, other researchers strongly disagreed with this estimate and proposed distances of up to three times this amount.

A revised Hipparcos analysis published in 2007 using the same data determined a very different parallax and a distance of about 1400 pc, much closer to other estimates.

A striking narrow-band image here shows the strong ionised oxygen emission from Sh 2-308, which the photographer calls the Gourd nebula.

RCW 12

Coordinates: (234.56°, 0.83°)
[ See details ]

Avedisova lists the ionising stars as the O9 V BD -18 1920 and the B3 III giant LSS 566. Other sources also include the B0V star MFJ Sh 2-307 3. The nebula contains the infrared cluster candidate [DBS2003] 8.

A 1995 paper places Sh 2-299, Sh 2-300, Sh 2-305, Sh 2-306, Sh 2-307 and Sh 2-309 into the same giant molecular cloud complex. A 1996 paper places Sh 2-305 to Sh 2-309 into molecular cloud [JKK96] D within the enormous infrared ring called the GS234-02 supershell, in the Perseus arm.

You can view the enormous dust ring around the supershell in this WISE infrared image. Sh 2-299 and Sh 2-300 also appear in this direction.

Both Avedisova and a 2007 paper, however, give much closer distance estimates and thus appear to exclude this nebula from the supershell.

You can view a good Dean Salman image of this nebula here.

RCW 13

Coordinates: (234.76°, -0.2°)
[ See details ]

Avedisova concludes that Sh 2-309 is ionised by the star cluster Bochum 6, including the O9 III giant LSS 499. She places it in star formation region SFR 234.76-0.20 along with the HII region Bran 42 and the emission star SS73 6.

The nebula contains the loose infrared cluster [DBS2003] 9.

A 1995 paper places Sh 2-299, Sh 2-300, Sh 2-305, Sh 2-306, Sh 2-307 and Sh 2-309 into the same giant molecular cloud complex. A 1996 paper places Sh 2-305 to Sh 2-309 into molecular cloud [JKK96] D within the enormous infrared ring called the GS234-02 supershell, in the Perseus arm.

You can view the enormous dust ring around the supershell in this WISE infrared image. Sh 2-299 and Sh 2-300 also appear in this direction.

RCW 14

Coordinates: (235.6°, -4.1°)
[ See details ]

RCW 14 appears to be a visible part of the [JKK96] B giant molecular cloud and is part of the GS234-02 supershell. The main ionising star is the O8 V star HD 57236.

Avedisova lists 3 additional B-class ionising stars and places RCW 14 in the star formation region SFR 235.54-4.06 along with the star cluster NGC 2367. The RCW catalog also associates RCW 14 with NGC 2367.

Kharchenko gives a distance of 2004 parsecs and an age of 10.2 million years for NGC 2367.

RCW 15

Coordinates: (237.25°, -6.5°)
[ See details ]

This vast nebula, one of the largest single HII regions known in the Milky Way, is ionised by two multiple star systems (Tau Canis Majoris and UW Canis Majoris) each made up of several O-class stars. This image shows only the brightest part of the enormous Sh 2-310 complex.

The intense radiation from the Tau Canis Majoris and UW Canis Majoris star systems has created a cavity in the molecular clouds at the centre of Sh 2-310, which is located beyond the upper right of the image.

Avedisova places Sh 2-310 in the star formation region SFR 237.25-6.50 with 62 components, including 4 masers, 14 infrared sources and the dark nebulae LDN 1660 and LDN 1664.

At least one scientific paper notes the "arrow-shaped bright rim" shown in this image. Perhaps Sh 2-310 should be known as the Arrowhead nebula?

RCW 16

Coordinates: (243.2°, 0.4°)
[ See details ]

NGC 2467, sometimes called the Mandrill nebula, is ionised by the ultrahot O3 V star HD 64568, the O6 IV subgiant HD 64315, and the B0 V star LSS 830, according to Avedisova. Besides the NGC 2467 star cluster itself, it includes the star clusters Haffner 18 and Haffner 19. The bright foreground star on the far left of the image is the B8 IV subgiant HD 64455.

It lies in the direction of the Pup OB1 and Pup OB2 associations (which overlap in the sky).

A good image of NGC 2467 is available in several resolutions from the European Southern Observatory. (Note: the ESO image is rotated 90 degrees, with north to the right.)

RCW 17

Coordinates: (243.5°, -1.0°)
[ See details ]

This is the planetary nebula NGC 2452.

RCW 18

Coordinates: (250.3°, -2.2°)
[ See details ]

According to SIMBAD, the only reference to this object in the scientific literature is the RCW catalog itself, which refers to it as a bright nebula 1 x 1 arcminutes in extent.

There is nothing visible in this SuperCOSMOS image, however, suggesting that this object may not exist.

RCW 19

Coordinates: (253.8°, -0.5°)
[ See details ]

RCW 19 is part of a 200 thousand solar mass giant molecular cloud related to the Pup OB3 association and the O7f III giant star HD 69464. This image shows only the bright rim of the larger RCW 19 complex.

Avedisova adds the O9.5 III giant CD -35 4412 as a second ionising star. She places RCW 19 in the star formation region SFR 253.75-0.50 with the molecular cloud [MAB97] 253.63+0.00 (this may be the cloud mentioned above) and the reflection nebulae Bran 124b, Bran 125b and VdBH 9.

You can see RCW 19 and RCW 20 together in this SuperCOSMOS hydrogen-alpha image, which also shows the boundaries of Pup OB3 and the newly discovered Kharchenko cluster [KPR2005] 45 (labelled ASCC 1045).

RCW 20

Coordinates: (254.5°, 0.0°)
[ See details ]

This is the HII region NGC 2579, which is ionised by three O-class stars. A 1998 paper argues that it is associated with RCW 19. However, a more recent 2007 paper gives a much greater distance for NGC 2579, placing it in the Norma arm.

Navigate to nebula [ Previous | Next ]

Alex Rodgers, Colin Campbell, and John Whiteoak, working at Australia's Mount Stromlo observatory under the direction of Dutch-American astronomer Bart Bok, published their nebula catalog in 1960. The RCW catalog is largely an expansion of Colin Gum's 1955 catalog. Although astronomers publish articles referring to the RCW 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 RCW objects are clearly visible only in long exposure CCD images or 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 southern hemisphere are in the RCW catalog so the 182 objects it contains are well worth examining carefully. (In fact there are more than 182 objects as subsequent research has shown that some of the RCW nebulae consist of more than one object.) At least 50 objects in the RCW catalog are also in the Sharpless catalog and I have noted this in the descriptions of these objects.

Most of the images used to illustrate the RCW catalog were created using the SuperCOSMOS Sky Survey, with red = hydrogen-alpha, blue = UKST Blue and 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.