One-of-a-Kind Supernova Remnant PA 30

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AVAO
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One-of-a-Kind Supernova Remnant PA 30

Post by AVAO » Tue Nov 14, 2023 9:40 pm

From an amateur PN candidate to the Rosetta Stone of SN Iax research
universe today
November 14, 2023 by Jon Voisey
An Amateur Astronomer Discovered One-of-a-Kind Supernova Remnant

In 2023, amateur astronomer Dana Patchick was looking through images from the Wide-field Infrared Survey Explorer archive and discovered a diffuse, circular object in the constellation of Cassiopeia. He found this apparent nebula was interesting because it was bright in the infrared portion of the spectrum, but virtually invisible in the colors of light visible to our eyes. ...

Although PA 30 was initially flagged as a potential planetary nebula, it quickly became apparent that it was anything but.

Just a year after its discovery, astronomers examined the object. With planetary nebulae, the central star has shed most of its outer layers resulting in the still extremely hot core of the star being exposed. The radiation from this star will heat the nebula created causing emission lines in the spectra. However, these emission lines were absent in the spectrum of PA 30.

Follow-up observations were conducted in 2016. These revealed winds from the central star at “unprecedented” speeds of 16,000 km/sec (5% the speed of light). Emission lines were found from the central star of highly ionized oxygen and carbon but both the central star and nebula lacked hydrogen and helium. The nebula was expanding with speeds of roughly 1,100 km/sec – as much as 100x the expansion speed of a typical planetary nebula.

However, these features don’t entirely line up with the expectations for a supernova either. First off, the expansion speed of the nebula was lower than most supernovae ejecta. Second, even in most supernovae, hydrogen and helium should still be present as it is the outer layer of the stars getting blasted off in the explosion.

The first attempt to explain this came in 2019. There, astronomers suggested that the supernova was caused by the merger of two white dwarfs which were both already depleted of these lighter elements as they released their atmospheres at the end of their main sequence lifetimes. Specifically, astronomers proposed that this was the merger of a white dwarf with a carbon/oxygen atmosphere with one with an oxygen/neon atmosphere creating an exceptionally rare type of supernova known as a SN Type Iax.

This proposition solves both of the problems. The previous loss of the atmospheres explains why hydrogen and helium were not present. Also, this type of supernova does not have as big of a bang as others, explaining the lower than anticipated expansion rate.

Further study supported this. Digging deeper into the spectra, the study found that the spectra had higher abundances than anticipated of neon and magnesium, which are the results of carbon fusion. This made PA 30 the only known supernova of this type within our galaxy.
...the whole story...

Arxiv: From an amateur PN candidate to the Rosetta Stone of SN Iax research
TY4YA Jac
Last edited by AVAO on Tue Nov 14, 2023 10:17 pm, edited 1 time in total.

User avatar
AVAO
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Posts: 808
Joined: Tue May 28, 2019 12:24 pm
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Location: Zurich, Switzerland

Re: One-of-a-Kind Supernova Remnant PA 30

Post by AVAO » Tue Nov 14, 2023 10:12 pm

The morphology of the Supernova Remnant PA 30 reminds me of the Nova GK Persei, although I know that you shouldn't compare Supernova remnants with Nova remnants...

"Classical novas can be considered to be “miniature” versions of supernova explosions. Supernovas signal the destruction of an entire star and can be so bright that they outshine the whole galaxy where they are found. Supernovas are extremely important for cosmic ecology because they inject huge amounts of energy into the interstellar gas, and are responsible for dispersing elements such as iron, calcium and oxygen into space where they may be incorporated into future generations of stars and planets.Although the remnants of supernovas are much more massive and energetic than classical novas, some of the fundamental physics is the same. Both involve an explosion and creation of a shock wave that travels at supersonic speeds through the surrounding gas. The more modest energies and masses associated with classical novas means that the remnants evolve more quickly. This, plus the much higher frequency of their occurrence compared to supenovas, makes classical novas important targets for studying cosmic explosions." more

Expanding Nebula around GK Persei. Images range from 1953 to 2012.
https://upload.wikimedia.org/wikipedia/ ... Persei.gif
User: Meli thev I own work I Wikipedia

“Mini Supernova” Explosion Could Have Big Impact Credit: NASA/ESA Chandra (optical) Credit: NASA/ESA Chandra (blue:X-ray pink:Radio)

GK Per (Nova Persei 1901): HUBBLE SPACE TELESCOPE IMAGERY AND SPECTROSCOPY OF THE EJECTA, AND FIRST SPECTRUM OF THE JET-LIKE FEATURE "(a) A net (Hα + [N ii] minus broadband R) image of the ejecta of GK Per, showing the “jet-like” feature extending to the northeast, and terminating in a very faint fan-like structure.
(b) Same as Figure 12(a) but stretched and shown as a negative to emphasize the faint but large-scale matter oriented NW to SE"
Michael M. Shara et al.



What is interesting is that in the Chandra data you can also see another bigger ring fragment (violet) that could possibly come from an earlier explosion (shockwave) ...

Click to view full size image 1 or image 2
jac berne (flickr)
Last edited by bystander on Wed Nov 15, 2023 3:58 pm, edited 1 time in total.
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