The mystery of the shining cosmic eye finally solved

In 2004, astronomers spotted a unique celestial feature that, when observed in ultraviolet light, has the appearance of a shining eye looking directly at Earth. Unbeknownst to them, it would take 16 years for them to figure out what caused the formation of the Blue Ring Nebula.

The Blue Ring Nebula is the remnant of two merging stars, according to the new research published today in Nature.

The bright yellow point in the center of the element is the surviving stellar remnant (the fusion of two stars); the blue ring is an expanding cloud of debris interacting with the stellar medium; and the magenta outline is the leading edge of the shock wave. To be clear, the blue and magenta colors seen in the nebula represent ultraviolet light, and they cannot be seen with the naked eye.

Colliding stars are constantly being spotted, so this discovery may not seem very special or exciting. What is special about all of this, however, is the timing of our observations, as astronomers are witnessing this stellar merger some 5,000 years after it occurred (excluding the time it took light to reach Earth). Typically, colliding stars are seen immediately after their smash-up..

“Merging two stars is quite common, but they quickly become obscured by a lot of dust as the ejecta expand and cool in space, which means we can’t see what really happened. Lead author Keri Hoadley explained. of the new study and a physicist at the California Institute of Technology, in a statement. “We believe this object represents a late stage in these transient events, when the dust finally clears and we have good eyesight.”

To which she added: “But we also got hold of the process before it got too far along; after a while the nebula will dissolve into the interstellar medium, and we couldn’t say anything at all.

The Blue Ring Nebula, therefore, is not something we have ever seen before, and it provides new science. The expanding blue ring, for example, is actually part of a pair. We can’t really see it from our perspective on Earth, but this nebula is actually shaped like two funnels connected together at their points., with the star merged in the center. These rings move away from each other in opposite directions, at speeds up to 250 miles per second (400 kilometers per second). The team calls this feature a “biconical symmetrical output,” and it provides important clues as to what happened in the fatal encounter.

Speaking at a press conference on Tuesday, Mark Seibert, co-author and astrophysicist at the Carnegie Institution for Science, said that “everything we have learned is interesting“And that the merged star” is one of a kind right now. “Indeed, this stellar object is a little weird, in that it is surrounded by a disc – the material from which flows directly into the star.

This story began in 2004 when Seibert, while participating in NASA’s Galaxy Evolution Explorer (GALEX) mission, was one of the first to contemplate the Blue Ring Nebula. At the time, Chris Martin, co-author of the new study and a physicist at Caltech, believed that “it was a really interesting object” and that his team “should produce a nice article within a year to explain it all,” As he told reporters yesterday.

This document “in the year”, however, was not to be, for the nature of the object remained elusive. Data collected by Caltech’s Hale Telescope at Palomar Observatory and the WM Keck Observatory in Hawaii revealed the presence of a shock wave around the star, which hinted at something violent and dramatic. A first hypothesis was that a hot Jupiter-like planet was caught in a death spiral around the star, and we were witnessing its destruction in the form of the nebula. But the researchers couldn’t be sure, and “ambiguities remained about this throughout the study,” Martin said.

Scientists also examined the status of the central star, known as TYC 2597-735-1, finding that it was quite old and was no longer burning hydrogen in its nucleus. Many other aspects of the object did not meet their expectations for the stars. Calling it a “Sherlock Holmes mystery,” Martin said it “became impossible to come up with a script to explain all of these sightings”, so “after a few years of study, we continued to do other things, and the project has been idle for a while.“

Things changed in 2017 when Hoadley joined Martin’s group as a postdoctoral fellow, and she seemed eager to take the lead on this hibernating project.

“I heard about it on the second day of my job and was immediately hooked,” she told the virtual show press conference.

The team had collected a lot of data, but their challenge was to “figure out how to put all the pieces together.And especially to determine how the nebula shone in the first place.

As the work progressed, however, the team began to realize that they were not dealing with a planet. and that the probable scenario involved a stellar collision. The mass of matter ejected by the star, for example, was too large for a planet, as Hoadley explained. Additionally, data collected by the Living Zone Planet Detector on the Hobby-Eberly Telescope in Texas found no evidence of a planet in this system.

Things got stranger when the team examined archival data collected by NASA’s Spitzer Space Telescope and Wide-field Survey Explorer (WISE), along with other infrared observatories. These data indicate the presence of an accretion disk around the star. Normally these dust rings are seen around young stars, but TYC 2597-735-1 is actually quite old.

To help understand all of this data, the team recruited astrophysicist Brian Metzger from Columbia University, an expert in cosmic fusions. Interestingly, Metzger’s mathematical and computer models agreed well with observations of the Blue Ring Nebula.

“It wasn’t just that Brian could explain the data we were seeing; it basically predicted what we observed before we saw it, ”Hoadley explained in a press release from Caltech. “He was like, ‘If this is a stellar fusion, then you should see X’, and it was like ‘Yes! We see that! ‘”

So here is the story of the Blue Ring Nebula, as revealed in the new document.

Thousands of years ago, a small star orbiting a larger star with roughly the same mass as our Sun. As the larger star grew older it became swollen, extend to reach very close to its smaller companion. The smallest star – about a tenth the size of our Sun – fell in a downward spiral that produced a gas disk. The large star eventually subsumed the smaller star, producing an expanding cloud of debris that was cut in half by the disc. This merger resulted in the two cone-shaped clouds of debris we see today.

Over the next thousands of years, the expanding cloud of debris cooled, forming hydrogen molecules that interacted with the stellar medium. Today, we see these collisions as bright ultraviolet emissions. The cloud “is now dissolving in the interstellar medium,And “we just get to catch it because all the exciting particles are there,” Hoadley told reporters.

Hoadley expects the Blue Ring Nebula to last for another thousand to tens of thousands of years, after which the function will disappear completely. It’s a real wink in cosmological terms and a wonderful opportunity to do fascinating science.