Mystery Blob Discovered Deep Inside a Supernova – “Not a Pulsar or a Black Hole”


SN1987A

In the fall of 1967, the great quantum physicist at Princeton, John Archibald Wheeler was giving a lecture on Pulsar at a conference, where he was arguing that we should consider the possibility that the center of gravity of a Pulsar completely collapsed. Is the object. He remarked that one cannot say that “the gravitational object has completely collapsed” again and again. We needed a short descriptive phrase. “How about a black hole?” Someone in the audience was asked, giving birth to the name of one of the most contradictory objects in the universe.

Fast forward to 2020, two teams of astronomers discovered a missing compact object that was supposed to have survived the supernova 1987A’s two-light-year widespread explosion, leaving them wondering if it was instead of a neutron star A black hole collided in one. A compelling case in the 33-year-old mystery is based on the observation of the Atacama Large Millimeter / Submillimeter Array (ALMA) and a theoretical follow-up study. Scientists provide new insights to the argument that a neutron star is hidden deep inside the remnants of an exploding star — it is the shortest known neutron star.

Missing evidence

Because the particles known as neutrinos were detected on Earth on 23 February 1987, astronomers expected a neutron star to have formed at the collapsing center of the star. But when scientists could find no evidence for that star, they wondered if it could be Wheeler’s “gravitationally collapsed object”. For decades, the scientific community has been eagerly waiting for a signal from this object that has been hidden behind a thick cloud of dust.

“Blob” in SN 1987A Original

Recently, observations from the ALMA radio telescope provided the first indication of a missing neutron star after the explosion. Extremely high-resolution images revealed a hot “blob” in the dusty core of SN 1987A, which is brighter than its surroundings and matches the suspicious location of the neutron star.

Mikako Matsura of Cardiff University and a member of the team said that we were very surprised to see this hot drop made of a thick cloud of dust in the supernova remnant, after mixing this drop with Alma. “There must be something in the cloud that warms the dust and shines through it. Therefore we suggested that a neutron star is hidden inside the dust cloud. “

Hot in dusty core of Supernova 1987A

The high-resolution ALMA images above detected a warm “blob” in the dusty core of Supernova 1987A (inset), which may be the location of the missing neutron star. The red color shows dust and cold gas at the center of the supernova remnant taken at radio wavelengths with ALMA. The green and blue color shows that the shock wave propagating from the exploded star is hitting a ring material around the supernova. The green represents a flare of visible light, captured by NASA’s Hubble Space Telescope. The blue color reveals the hottest gas and is based on data from NASA’s Lunar X-ray Observatory. The ring was initially made to shine by a flash of light from the original explosion. In later years the ring material has become quite luminous as it contains an explosion shock slam.

Even though Matsuura and his team were excited by the result, they thought about the brightness of the blob. “We thought the neutron star might be too bright to exist, but then Dan Page [an astrophysicist at the National Autonomous University of Mexico] And his team published a study that indicated that the neutron star might actually be brighter because it is so small, ”said Matsura.

“I was halfway through my PhD when the supernova took place,” said Page, “It was one of the biggest events of my life, which made me take the course of my career to try to solve this mystery.” Changed. It was like a modern sacred tomb. “

“Despite the supreme complexity of a supernova explosion and extreme conditions ruling the interior of a neutron star, detecting a hot drop of dust is a confirmation of many predictions,” Page explained in a theoretical study of Page and her. The team, published today in the Astrophysical Journal, strongly supports the suggestion by the ALMA team that a neutron star is blowing dust.

Predictions -Location and Temperature

These predictions were the location and temperature of the neutron star. According to the supernova computer model, the explosion “kicked” the neutron star from its birthplace with a speed of hundreds of kilometers per second (ten times faster than the fastest rocket). The drop is exactly where astronomers think the neutron star would be today. And the temperature of the neutron star, which was predicted to be around 5 million degrees Celsius, provides enough energy to explain the brightness of the blob.

“Possibly not pulsar”

“The strength of a pulsar depends on how fast it rotates and the strength of the magnetic field, both requiring very finely tuned values ​​to match the observations, while the young neutron star’s hot The data fits the thermal energy emitted by the surface, Page said, suggesting that contrary to common expectations, the neutron star — a 25 km-wide, extremely hot ball of ultra-dense material — is probably not pulsar. One of its contents The spoon will weigh more than all buildings within United New York City. Because it can only be 33 years old, it will be the youngest neutron star ever. The second youngest neutron star we know of is the supernova remnant Cassiopeia A. And is 330 years old.

“The neutron star behaves exactly as we expect,” James Latimer of Stony Brook University in New York and a member of Page’s research team. Lattimer also closely followed SN 1987A, which was published before SN 1987A, an approximation of the neutrino signal of supernovae that matched later observations. “Those neutrinos suggested that a black hole is never formed, and furthermore it seems difficult for a black hole to explain the observed brightness of a blob. We compared all the possibilities and concluded that a hot neutron star is the most likely explanation. “

Waiting for dust to settle

Only a direct picture of the neutron star will provide definitive evidence that it exists, but astronomers may have to wait a few more decades until the dust and gas in the supernova remnant become more transparent.

Although many telescopes have produced SN 1987A images, none of them have been able to observe its origin with high precision like ALMA. Observations with the first (3-D) ALMA showed the types of molecules already found in the supernova residue and confirmed that it produced a large amount of dust.

“This discovery builds on years of ALMA observations, showing the core of the supernova in greater detail for continued improvements in telescopes and data processing,” said Remy Indebetouw of the National Radio Astronomy Observatory and the University of Virginia, which provides ALMA imaging Has been a part of the team.

Source: ALMA Overview of “Blob”: p. Saigan et al. “High Angular Resolution ALMA Images of Dust and Molecule in SN 1987A Ezeka” by The Astrophysical Journal. https://doi.org/10.3847/1538-4357/ab4b46

Theoretical study in favor of a neutron star: “NS 1987 in SN 1987A”, d. The Astrophysical Journal, by Page et al. https://doi.org/10.3847/1538-4357/ab93c2

Daily Galaxy, Max Goldberg, via NRAO

Image credit: Chandra X-ray Observatory of Page and inset ALMA (ESO / NAOJ / NRAO), p. Saigan and R. Indebetouw; NRAO / AUI / NSF, B. Saxton; NASA / ESA

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