Heart Nebula, IC 1805, Running Dog Nebula, Sharpless 2-190
Constellation: Cassiopeia
Type: Emission Nebula
RA: 02h 33m 22s
Dec: +61°26’36”
Mag: 6.5
Size: 150' x 150'
Soul Nebula, Westerhout 5, Embryo Nebula, Sharpless 2-199, LBN 667, IC 1848 (open cluster)
Constellation: Cassiopeia
Type: Emission Nebula, Open Cluster
RA: 02h 55m 24s
Dec: +60°24’36”
Mag: 6.5
Size: 150' x 75'
Stein 368
Constellation: Cassiopeia
Type: Double Star
RA: 02h 32m 49s
Dec: +61°27’00”
Mag: 8.0, 10.1
Size: 10”
The constellation Cassiopeia is home to a large number of open clusters. There are over two dozen open clusters that are readily visible in amateur telescopes. At least another fifty open clusters have been identified in the constellation photographically. Our Object of the Week consists of a complex of multiple emission nebulae and open clusters. This complex region is a beautiful and photogenic and therefore is a frequent target of astrophotographers. Sadly much of the nebulosity and beauty of this region is not visible in amateur telescopes. As a result these objects are often ignored by visual astronomers. The challenge I present to you is to get out under the darkest skies you’re able, sprinkling in at least average transparency if not better, and begin your hunt for The Heart and Soul Nebulae.
The Heart Nebula (IC 1805) is an emission nebula located at an approximate distance of 7,500 light years. It is also known as Sharpless 2-190 (Sh2-190) or the Running Dog Nebula because, when seen through a telescope, it looks a bit like a running dog. The nebula has a magnitude of 6.5. It is 150 arcminutes in size and known for its intensely red glowing gas and dark dust lanes forming a shape that resembles a heart symbol.
The Heart Nebula forms this complex with its smaller neighbor Westerhout 5, more commonly known as the Soul Nebula. The Heart and Soul Nebulae complex spans an area about 300 light years across and is a vast star-forming region illuminated by the light of the young stars surrounded by star-forming clouds of dust and gas. The two large clouds are separated by only 2.5 degrees and physically connected by a bridge of gas. The stars in the region are less than a few million years old and are only beginning their life. For comparison, our Sun has been around for almost 5 billion years.
Both nebulae shine bright in red light due to the emission of that specific color of light by the excited nearby hydrogen gas. The nebulae form a large star-forming complex in the Perseus Arm of the Milky Way. The clusters found in the region belong to the Cas OB6 association.
The brightest part of the Heart Nebula has the designation NGC 896 in the New General Catalogue. It is classified separately because it was the first part of IC 1805 to be discovered.
The nebula’s glow comes from the radiation of a small open cluster of stars known as Melotte 15. The cluster contains very young, blue, hot supergiant stars about 1.5 million years old. It is located near the nebula’s center and home to several bright stars with a mass almost 50 times that of the Sun, as well as many faint stars far less massive than the Sun.
The Heart and Soul region contains a total of seven open clusters of young stars. Two of these, IC 1805 and IC 1848, are directly associated with the nebulae and share the catalogue designations with them. The others are Basel 10, occupying only 2 arcminutes of the sky, NGC 957 (10 arcminutes), and Berkeley 65 (5 arcminutes). Rounding off the group is the famous Double Cluster (the Sword Handle) in Perseus, formed by two bright, large open clusters known as h and Chi Persei or NGC 869 and NGC 884. The Heart Nebula lies only 5 degrees to the northwest of the Double Cluster.
The Heart & Soul Region.jpeg
The Heart Nebula lies in the vicinity of Maffei 1 (PGC 9892) and Maffei 2 (UGCA 39), the brightest galaxies in the IC 342/Maffei Group, the nearest galaxy group to our Local Group. The galaxies are difficult to find and observe as they are obscured by the Milky Way’s dust and stars, and their features are not easy to make out. Both galaxies – the elliptical Maffei 1 and the intermediate spiral Maffei 2 – were discovered in 1967 by the Italian astronomer and infrared astronomy pioneer Paolo Maffei, who detected the galaxies via their infrared emissions. Each galaxy contains billions of stars. At an approximate distance of 10 million light years, they are relatively close to the Milky Way compared to most known galaxies.
The central star of the Heart Nebula is the double star Stein 368 which shows a faint companion 10” to the east.
The Soul Nebula (Westerhout 5) is also an emission nebula. It is also known as the Embryo Nebula or IC 1848, which is a designation used for the open star cluster embedded within the nebula.
Westerhout 5 is about 100 light years across and has an estimated age of 1 million years. It contains several small open stars clusters. IC 1848 is embedded in the body of the nebula, while the clusters CR 34, 632 and 634 can be seen in the head. Small emission nebulae IC 1871, 670 and 669 are located just next to the Soul Nebula.
The nebula is being carved out by the stellar winds from the stars embedded within it, a process that leaves behind large pillars of material pointing inwards. These pillars are very dense and have stars forming at their tips. Each pillar spans about 10 light years.
Here are a two observing reports from Christian B. Luginbuhl and Brian A. Skiff taken from their book Observing Handbook and Catalogue of Deep-Sky Objects.
IC 1805
diam. 22' V = 6.5 Stars 62
This cluster is involved with an extended faint nebulo-sity. At low power, 6 cm will show a conspicuous clustering of about 25 stars embedded in a very faint haze. 25 cm shows a loose aggregation of about ten brighter stars and as many fainter ones in a 20' area, but no nebulosity is visible. In 30 cm, the bright mag. 8.5-9 stars are scattered in a 25' area. Near the center, grouped about a mag. 8 star, are 25 stars within 5' diameter.
IC 1848
diam. 12' V = 6.5 Stars 74 dimen. 40’ x 10”
This cluster is more definitely associated with nebulosity than oc-gn IC 1805, cf., in 6 cm. The stars are also fainter, less concentrated toward the center, and strung out to the E and W. No nebulosity is visible with 25 cm, but 65 stars, mostly mag. 11, can be seen in a 30' area. On the E side of the 8' core is a mag. 7 star. 30 cm shows the cluster stars grouped around the mag. 7 star and a mag. 8 star 2' SSE. The fainter star is surrounded by 12 stars in a 2' area with strings extending to the NE and SW. The brighter star is accompanied by eight stars in a l' area. Some nebulosity is visible around the bright stars.
Now it is your turn. Give it a go and let us know.
Heart-and-Soul-640x454.jpeg
The Heart and Soul nebulae are seen in this infrared mosaic from NASA’s Wide-field Infrared Survey Explorer, or WISE. Also visible near the bottom of this image are two galaxies, Maffei 1 and Maffei 2. Maffei 1 is the bluish elliptical object and Maffei 2 is the spiral galaxy. All four infra-red detectors aboard WISE were used to make this image. Colour is representational: blue and cyan represent infra-red light at wavelengths of 3.4 and 4.6 microns, which is dominated by light from stars. Green and red represent light at 12 and 22 microns, which is mostly light from warm dust. Image: NASA/JPL-Caltech/UCLA
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