Using the Hubble Space Telescope (HST), astronomers conducted near-ultraviolet observations through close infrared observations of a young planetary nebula (PN) known as NGC 6302. The results of a monitoring campaign presented on May 28 on arXiv.org could help us better understand the essence of this PN.
PNe are expanding shells of gas and dust that have been ejected from a star during the process of its evolution from a star of the main sequence into a red giant or white dwarf. They are relatively rare, but are important to astronomers studying the chemical evolution of stars and galaxies.
Located about 3,400 light-years in the constellation Scorpio, NGC 6302 (also known as the Bug Nebula, Butterfly Nebula, or Caldwell 69) is a two-bladed PN rich in dust and molecular gas. Its relative proximity makes it a great target for high-resolution images aimed at understanding the origin and evolution of bipolar structures in the population of known PNe.
Therefore, a team of astronomers led by Joel H. Kastner of the Rochester Institute of Technology (RIT) used Hubble’s Wide Range Camera 3 (WFC3) to obtain comprehensive, state-of-the-art sets from near UV to near IR (243 nm to 1.6). µm) emission images of NGC 6302.
“Here we present the full set of HST / WFC3 images of NGC 6302, along with various line ratio images and a detailed study of the key results obtained from these images so far,” the researchers wrote in the article.
Hubble images show that NGC 6302 has a dusty toroidal equatorial structure that splits into two polar lobes of PN and fine structures (such as lumps, nodes, and filaments) in the lobes. Such morphology is extremely unusual for bipolar PNe, except for some multipolar PNe.
The study identified an unexpectedly bright, S-shaped 1.64 µm [Fe II] emission in NGC 6302, which traces the southern interior of the edge of the eastern lobe and the northern interior of the edge of the western lobe. Astronomers have suggested that this may be a zone of shock caused by ongoing, fast, colliding winds from the central star of PN.
In addition, the study found that the object previously identified as the central star of NGC 6302 was in fact a foreground field star. The researchers added that a pair of bubble-like characteristics in the core of NGC 6302 probably showed the actual position of the central star in the dusty central torus of the PN. However, more observations with a mean IR and submillimeter wave resolution are needed to confirm this.
In concluding remarks, the authors of the article note that the results emphasize the mysterious nature of NGC 6302.
“The characteristics revealed by our panchromatic HST / WFC3 images of NGC 6302 – in particular, its individual azimuthal structural zones and nested balloon system, as well as the surprising discrepancy of the current collimated fast wind direction of the central engine (as traced by 1.64 Um [Fe II] emission) and the main axis of symmetry of the nebula (as determined by the dusty molecular torus, a blind system with a polar axis and outer walls of the lobes) – is a particularly daunting challenge for models of origin and evolution of bipolar structures in PNe, “the researchers concluded.
Astronomers dissect the anatomy of planetary nebulae using images from the Hubble Space Telescope
Panchromatic HST / WFC3 imaging of young, fast-growing planetary nebulae. I. NGC 6302, arXiv: 2105.13953 [astro-ph.SR] arxiv.org/abs/2105.13953
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Quote: Astronomers probe planetary nebula NGC 6302 with Hubble (2021, June 8) extracted on June 9, 2021 from https://phys.org/news/2021-06-astronomers-probe-planetary-nebula-ngc.html
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