In 2004, astronomers noticed a unique celestial feature that, observed in ultraviolet radiation, had the appearance of a glowing eye staring back at the Earth. Without their knowledge, it will take 16 years to understand what caused the formation of the Blue Ring Nebula.
The Blue Ring Nebula is the remnant of two merging stars, according to new ones research published today in Nature.
The bright yellow dot in the center of the characteristic 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 contour is the leading edge of the shock wave. To be clear, the blue and purple colors observed in the nebula are ultraviolet light and cannot actually be seen with the naked eye.
Colliding stars are noticed all the time, so this discovery may not look particularly special or exciting. What is special about all this, however, is the time of our observations, as astronomers have witnessed this stellar merger about 5,000 years after it occurred (excluding the time during which light reached Earth). Usually, the colliding stars are seen immediately after they break.
“The merging of two stars is quite common, but they quickly become obscured by a lot of dust as the ejection of them expands and cools in space, which means we can’t see what actually happened,” explained Carrie Hodley, host. author of the new study and physicist at the California Institute of Technology, in a statement. “We think this site is a late stage in these transitional events, when the dust is finally cleared and we have a good view.”
To which she added: “But we also caught the process before it was too far; in time, the nebula will dissolve into the interstellar medium, and we could not say at all that something had happened. “
The Blue Ring Nebula, therefore, is not something we have seen so far, and it provides new science. The expanding blue ring, for example, is actually one of a pair. We really can’t see it from our point of view on Earth, but this nebula is actually shaped like two funnels connected together at their points.,, with the merged star 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 ebb” and provides some important clues about what happened during the fatal encounter.
Speaking at a news conference Tuesday, Mark Seibert, co-author and astrophysicist at the Carnegie Institution of Science, said “everything we’ve learned is interesting.“And that the United Star” is one of a kind at the moment. “Actually, this stellar object is kind of weirdbecause it is surrounded by a disk – the material from which it is poured 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 look into the Blue Ring Nebula. At the time, Chris Martin, co-author of the new study and a physicist at Caltech, thought “this is a really interesting object” and that his team “should come up with a good paper within a year to explain it all,” he said. in front of journalists yesterday.
However, this article “within the year” did not have to be, as the nature of the object remained elusive. Data collected by the Caltech Hale Telescope at the Palomar Observatory and the WM Keck Observatory in Hawaii reveals a shock wave around the star that hints at something violent and dramatic. The early hypothesis was that a hot planet similar to Jupiter was caught in a spiral of death around the star and we witnessed its destruction in the form of a nebula. But researchers could not be sure, and “ambiguities remained throughout the study,” Martin said.
The researchers also studied the condition of the central star, known as TYC 2597-735-1, and found that it is quite old and no longer burns hydrogen in its core. Many other aspects of the object did not meet their expectations of the stars. Calling it the “Sherlock Holmes Mystery,” Martin said it “became impossible to come up with a scenario to explain all these observations,” so that “after several years of research, we kept doing other things, and the project fell asleep for a while.”
Things changed in 2017 when Howdley joined Martin’s group as a postdoctoral fellow and she seemed eager to take over this hibernation project.
“I heard about it on the second day of work and I was immediately hooked,” she told the virtual press conference.
The team had gathered a lot of data, but her challenge was to “figure out how to put it all together.”And to determine in particular how it was that the nebula lit up in the first place.
As the work progressed, however, the team began to realize that it was not dealing with a planet and that the likely scenario involves a stellar collision. The mass of material ejected from the star, for example, is too large for a planet, Houdley explained. Moreover, data collected by the Habitable Zone Planet Finder of the Hobby-Eberly Telescope in Texas found no evidence of a planet in this system.
Things got weirder when the team looked at archival data collected by NASA’s Spitzer Space Telescope and the Wide Field Survey Explorer (WISE), along with other infrared observatories. These data indicate the presence of an accretion disk around the star. Usually these dust rings are seen around young stars, but TYC 2597-735-1 is actually quite old.
To help make sense of all this data, the team appointed astrophysicist Brian Metzger of Columbia University, an expert on space mergers. Excitingly, Metzger’s mathematical and computational models blended well with observations made by the Blue Ring Nebula.
“It wasn’t just Brian who could explain the data we saw; he was essentially predicting what we watched before he saw it, “Howley said in a press release from Caltech. He would say, “If this is a stellar merger, then you should see X” and it was like “Yes! We see this! “
So, here is the story of the Blue Ring Nebula, as revealed in the new document.
Thousands of years ago, a small star orbited a larger star with about the same mass as our Sun. As the larger star grows, however, it swells, expands to reach very close to its smaller companion. The smaller star – about a tenth the size of our Sun – fell in a descending spiral that formed a gaseous disk. The big star eventually turned on the smaller star, creating an expanding cloud of debris that was cut in half by the disk. This merger resulted in two clouds of cone-shaped debris that we see today.
Over the next thousands of years, the expanding cloud of debris cools, forming hydrogen molecules that interact with the stellar environment. Today we see these collisions as bright ultraviolet emissions. Now the cloud is “dissolving in the interstellar medium,“And ‘we’re just catching it, because all the exciting particles are there,'” Howley told reporters.
Hoadley expects the Blue Ring Nebula to continue for another thousand to several tens of thousands of years, after which the feature will disappear completely. This is a real blink of an eye in cosmological terms and a wonderful opportunity to engage in a fascinating science.