Examples of nebula
Pro Research Analysisby 
Searched over 200M research papers
Examples of Nebulae: A Comprehensive Overview
High-Ionization Nebulae in Galaxies
NGC 55 High-Ionization Nebula
One notable example of a high-ionization nebula is found in the galaxy NGC 55. This nebula, identified as TR 001507.7-391206, is characterized by its very high temperature and excitation levels. The emission line spectrum, which includes He II, suggests photoionization by approximately three very hot massive O3 or Wolf-Rayet (WR) type stars. This nebula is not a supernova remnant, as indicated by the faint blue optical continuum and XMM-Newton EPIC-pn and OM-data.
Wolf-Rayet Nebula G2.4+1.4
Another example is the highly ionized nebula G2.4+1.4 surrounding the Wolf-Rayet star WR 102. This nebula has a relatively smaller diameter of about 11 parsecs compared to the 58 parsecs of the nebula in NGC 55, but both are consistent with the presence of ionizing stars.
Planetary Nebulae in Open Clusters
Planetary Nebula in M37
A significant example of a planetary nebula within an open cluster is found in M37 (NGC 2099). This large, evolved, bipolar planetary nebula, along with its blue, white dwarf central star, is confirmed to be a member of the approximately 500 million-year-old Galactic open star cluster M37. The association is supported by consistent radial velocities, proper motions, and reddening agreement. This nebula provides valuable data for understanding the stellar initial-to-final mass relation.
High-Mass Planetary Nebula in NGC 6067
Another example is the planetary nebula BMP J1613-5406, associated with the Galactic star cluster NGC 6067. This nebula is notable because its progenitor star had a mass of around five solar masses, which is near the theoretical lower limit for core-collapse supernova formation. This finding supports the prediction that stars of five solar masses and more can form planetary nebulae.
Dark Nebulae in the Large Magellanic Cloud
Dark Nebulae Characteristics
In the Large Magellanic Cloud, 68 dark nebulae have been identified using Schmidt plates. These nebulae are generally larger than those in the Milky Way and often show alignment with the bar of the galaxy. There is also a strong suggestion of elongation of the dust clouds parallel to the magnetic field.
Star Formation in the Orion Nebula Cluster
Formation History of the Orion Nebula Cluster
The Orion Nebula Cluster (ONC) is an excellent example for studying star cluster formation. Recent studies have shown that the ONC has three distinct age populations and anisotropy in velocity dispersions. These characteristics are key to understanding its formation history, which involves hierarchical formation and episodic star formation driven by clump mergers. This process brings cold gas into the cluster center, enhancing star formation and contributing to the anisotropy in velocity dispersions.
Conclusion
Nebulae, whether high-ionization, planetary, or dark, provide critical insights into the processes of star formation and the evolution of galaxies. From the high-ionization nebulae in NGC 55 and around WR stars to the planetary nebulae in open clusters like M37 and NGC 6067, and the dark nebulae in the Large Magellanic Cloud, each type of nebula offers unique information that enhances our understanding of the universe. The Orion Nebula Cluster further exemplifies the dynamic processes involved in star cluster formation. These examples underscore the diversity and complexity of nebulae in different galactic environments.
Sources and full results
Most relevant research papers on this topic