Astronomers had never seen anything like the fireworks display of this unique dying star. Supernovae, the explosion of dead stars, typically release a tangled web of gas and dust. But the remnants of a supernova look completely different in a recent photo; they seem to ignite a cosmic fireworks display. This is the strangest remnant ever discovered by experts and could be a sign of a particularly rare type of supernova that astronomers have long sought to understand.
"I've been studying supernova remnants for 2017 years, and I've never seen anything like it," says Robert Fesen, an astronomer at Dartmouth College in Hanover, New Hampshire, who captured an image of the remnant in late 30.
On January 12, he presented his research at the American Astronomical Society meeting and published it in an unexamined publication.
The celestial object was found in 2013 by amateur astronomer Dana Patchick in archive photos of the Wide Field Infrared Survey Explorer. Over the next decade, many teams analyzed the Pa 30 residue, but the findings were consistently confusing.
Russia's Lomonosov Moscow State University astronomer Vasilii Gvaramadze and his team discovered a truly unique star in the middle of Pa 2019 in 30. The stellar wind from this star was moving away at 16.000 kilometers per second, or about 5% of the speed of light, and had a surface temperature of about 200.000 kelvin.
Fesen claims that winds moving at 16.000 km/s are not found in stars. Fesen claims that speeds in excess of 4,000 km/h are not unheard of, but 16,000 is insane.
The mystery surrounding the object was revealed once more in 30, when astronomer Andreas Ritter of the University of Hong Kong and colleagues claimed that Pa 850 was the remnant of a supernova that lit up the sky about 1181 years ago, in 2021. The object was detected by Chinese and Japanese astronomers for about six months before disappearing.
Ritter and colleagues studied Pa 30 and found that the residue has a unique line in the emission spectrum connected to the element sulphur. Fesen's team was so intrigued that they eventually scanned the relic with an optical filter sensitive to this line using the 2,4-metre Hiltner Telescope at the Michigan-Dartmouth-MIT Observatory in Kitt Peak, Arizona.
The data they gathered produced a unique image of the remnant, as well as confirming that Pa 30 was what was left of the supernova seen in 1181. It has many thin filaments radiating outward.
Scientists typically expect supernova remnants to resemble the Crab Nebula, with a smooth patch in the middle of an oval-shaped filament mass that resembles tentacles rather than a crab. They also often resemble the Tycho Supernova, appearing as a sphere of scattered knots.
The Pa 30, on the contrary, is “an unbelievable sight,” according to Saurabh Jha, an astronomer at Rutgers University in Piscataway, New Jersey. This is something I've never seen before. It's truly mind-blowing.
Death of the Supernova
What could be the cause of such a residue? In 2021, Ritter and his colleagues hypothesized that it was an unusual supernova explosion of uncertain type.
A typical type-Iax (ordinary or obscure) supernova occurs when a white dwarf absorbs matter from a partner star. Eventually, the white dwarf becomes so large that it cannot support the extra weight and explodes, scattering its contents throughout the galaxy. However, the star manages to survive with an ordinary type supernova. “We often call them zombie stars,” explains Jha.
Ritter and colleagues believe that two white dwarfs collided to produce Pa 30's fireworks, although scientists have developed several potential explanations for obscure-type supernovae. This is evident from the abundance of sulfur in the remnant as a result of the white dwarf explosion, and the absence of lighter components that would be expected from higher-mass stars.
According to astronomer Anthony Piro of Carnegie Observatories in Pasadena, California, these results “crystallize at least one way in which the Iax type could arise.” The previously preferred scenario, a white dwarf siphoning material from a partner, is out of the question here. This hypothesis emerged in 2014 when scientists successfully identified stars involved in an explosion by examining pre-event photos.
In light of this, Jha claims that the discovery of Pa 30 "definitely expands on what, in my view, might have caused an indeterminate type supernova."
These rare explosions are difficult to investigate, as they often occur in distant galaxies. However, Pa 30 is only 2,3 kiloparsecs away, meaning that subsequent observations will provide more information about this rare supernova type (assuming it's actually an ordinary type).
Fesen has already requested observation time for both the old James Webb Space Telescope and the Hubble Space Telescope (JWST). According to Fesen, “I think the optical image taken just gives an idea of what it actually looks like.” But the JWST image will be incredible.
Source: nature.com/articles/d41586-023-00202-1
Günceleme: 29/01/2023 20:20
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