Calabash Nebula
A protoplanetary nebula in Puppis, near NGC 2438.
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The Calabash Nebula, also known as the Rotten Egg Nebula or by its technical designation OH 231.84 +4.22, is a protoplanetary nebula (PPN) located in the constellation Puppis. It is notable for its elongated shape, spanning 1.4 light-years, and its association with the open cluster Messier 46, sharing the same distance, radial velocity, and proper motion.
Lore & Background
The Calabash Nebula was first proposed under that name in 1989 in an early paper on its expected nebular dynamics, based on its appearance. It is almost certainly a member of the open cluster Messier 46, as it has the same distance, radial velocity, and proper motion.
The central star is QX Puppis, a binary composed of a very cool Mira variable and an A-type main-sequence star. In wide field images, the Calabash Nebula is visible near the bright planetary nebula NGC 2438 in deep photographs. Although the Calabash Nebula is at the same distance as M46, NGC 2438 is a larger object in the foreground.
Reader's Guide
The Calabash Nebula holds significance as a protoplanetary nebula, representing a transitional phase in stellar evolution. Its association with the open cluster Messier 46 provides a rare opportunity to study a PPN within a known stellar grouping, offering insights into the dynamics and evolution of such objects.
The nebula's distinctive shape and the presence of a binary central star—a cool Mira variable paired with an A-type main-sequence star—add to its scientific interest. Ground-based imagery, such as that taken from the Mount Lemmon SkyCenter using the 0.8 m Schulman Telescope, has captured the Calabash Nebula alongside NGC 2438, highlighting its position in the sky. The nebula's legacy is further cemented by its inclusion in astronomical catalogs and its popular monikers, the Rotten Egg Nebula and the Calabash Nebula, which reflect its visual and chemical characteristics.
More in Emission, Dark and Reflection Nebulae
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Calabash Nebula (CC BY-SA 4.0).
- Word definitions: the Codexery glossary, each quoted from its Wikipedia article.
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