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This magnificent detailed image shows the majestic petals of the flower shaped Wolf Rayet bubble nebula G2.4+1.4 in the field of the Milky Way in the constellation of Sagittarius. Once considered to be a supernova remnant, professional astronomers in 1990 found it to be a mass loss ejecta nebula created by the Wolf Rayet star WR 102.
This is a rare example of an optical Wolf Rayet nebula associated with a WO category WR star, which consist primarily of oxygen. The majority of WR nebulae contain Wolf Rayet stars belonging to the categories of either WN (nitrogen) or WC (carbon). WO type stars are extremely rare with very few located in the Milky Way.
The distance to G2.4+1.4 is 18,000 light years and is affected by dust obscuration and would be brighter if it was closer and not reddened by dust. The structure consists of a brighter inner bubble surrounded by multiple fainter filaments that are visible with long Ha and OIII exposures. Observations by professional astronomers have shown that the nebula is visible in radio and infrared wavelengths and appears brighter in the infrared in comparison to its optical emission.
Over the decades, many theories have been put forward to explain its marvellous structure. Some explanations involve a wind blown bubble interacting with low density gas as well the off centre position of WR 102 in relation to the nebula being caused by the proper motion of the star.
The image includes a few other interesting objects. To the left is the small red ring shaped planetary nebula Sab 27, whose discovery was first announced in 1997 by the astronomer Franco Sabbadin. In the following year in 1998, it was confirmed to be a true planetary nebula in the MASH survey. It might belong to the rare class of quadrupolar planetary nebulae and is also catalogued as PN G002.4+01.1 and also known as the Cell Nebula.
To the right is the golden globular cluster Pal 6, which lies in the neighbouring constellation of Ophiuchus at a distance of 23,000 light years. It was discovered by the astronomer George Abell in 1952 and is very unique as it is one of four globular clusters in the Milky Way known to contain a planetary nebula. The PN inside Pal 6 was discovered in 1997 by George Jacoby and Laura Fullton and is called JaFu 1. It can actually be seen in the full resolution image as a small red blob located above and to the left of Pal 6. The size of JaFu 1 is 0.8 light years and has the largest absolute size in comparison with the other globular cluster planetary nebulae. The other planetary nebulae that have been found in globular clusters are JaFu 2 in NGC 6441, GJJC 1 in M22 and Pease 1 in M15. Planetary nebulae have also been discovered in globular clusters belonging to other galaxies.
Full res version here
Labeled version here
Description and labeled version thanks to Sakib Rasool
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