Using the Hubble Space Telescope (HST), astronomers have conducted near-ultraviolet through near-infrared observations of a young planetary nebula (PN) known as NGC 6302. The results of the monitoring campaign, presented on May 28 on arXiv.org, could help us better understand the nature of this PN.
PNe expands shells of gas and dust that have been pushed out of a star during the process of its evolution from a main sequence star to a red giant or white dwarf. They are relatively rare, but are important for astronomers studying the chemical evolution of stars and galaxies.
NGC 6302 (also known as Bug Nebula, Butterfly Nebula or Caldwell 69) is approximately 3,400 light-years away in the constellation Scorpius (also known as Bug Nebula, Butterfly Nebula or Caldwell 69). Its relative proximity makes it a good target for high-resolution images aimed at understanding the origin and evolution of bipolar structures in the population of known PNe.
Therefore, a group of astronomers led by Joel H. Kastner of the Rochester Institute of Technology (RIT) used Hubble’s Wide Field Camera 3 (WFC3) to obtain comprehensive, simultaneous sets of near UV through near IR (243 nm to 1.6 µm) emission line images of NGC 6302.
“Here we present the full series of HST / WFC3 images of NGC 6302 along with various line ratio images and a detailed study of the main results obtained from these images so far,” the researchers wrote in the newspaper.
Hubble images show that NGC 6302 has a dusty, toroidal equatorial structure that intersects PN’s polar lobes and fine structures (such as lumps, knots, and filaments) within the lobes. Such morphology is very unusual for bipolar PNe, except for certain multipolar PNe.
The study identified an unexpected light, S-shaped 1.64 µm [Fe II] emission in NGC 6302, which tracks the southern interior of the eastern edge and the northern interior of the western edge. Astronomers assume this may be a zone of shock caused by ongoing, rapid, collimated winds from PN’s central star.
Furthermore, the research found that the object previously identified as the central star in NGC 6302 is actually a foreground field star. The researchers added that a few bubble-like features in the core region of NGC 6302 probably indicate the central star’s actual position within PN’s dusty central torus. However, several observations are required below the resolution of the second arc in the center of the IR and submillimeter wave bands to confirm this.
In the concluding remarks, the authors of the paper noted that the results underscore the mysterious nature of NGC 6302.
“The features revealed by our panchromatic HST / WFC3 images of NGC 6302 – especially its distinct azimuthal structural zones and embedded bubble system and the surprising displacement of the central engine’s current collimated fast wind direction (track of 1.64 µm [Fe II] emission) and the main axis of the nebulae for symmetry (as defined by its dusty molecular torus, pole axis lump system and outer patch walls) – represent a particularly daunting challenge for models of the origin and evolution of bipolar structures in PNe, “the researchers concluded.
Astronomers dissect the anatomy of planetary nebulae using Hubble Space Telescope images
Panchromatic HST / WFC3 Imaging Studies of young, rapidly evolving planetary nebulae. I. NGC 6302, arXiv: 2105.13953 [astro-ph.SR] arxiv.org/abs/2105.13953
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Citation: Astronomers study planetary nebula NGC 6302 with Hubble (2021, June 8) retrieved June 9, 2021 from https://phys.org/news/2021-06-astronomers-probe-planetary-nebula-ngc.html
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