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Have Astronomers Discovered One Other “Alien Megastructure” Star?

Scientists now have a second example of a strange stellar phenomenon speculatively linked to extraterrestrial intelligence in 2015 A far…

Scientists now have a second example of a strange stellar phenomenon speculatively linked to extraterrestrial intelligence in 2015

 Have Astronomers Found Another

A far away star in the southern sky is flickering in an odd way that suggests a weird cloud of material-or something even stranger-is in orbit around it. Discovered by astronomers using a telescope in Chile, the star is reminiscent of two other enigmatic astrophysical objects, one thought to harbor a planet with rings 200 times larger than those of Saturn, the other most famous for the remote possibility it is encircled by “alien mega structures. “The newfound star may help shed some light on one or both of these puzzling objects.

In 201

0, the Vista Variables in the Via Lactea (VVV) survey began its project of creating a three-dimensional map of variable stars in the vicinity of the Milky Way’s center. As a part of the project, astronomer Roberto Saito of the Federal University of Santa Catarina scoured the telescope’s data for eruptive outbursts from the hundreds of millions of monitored stars. Men den mest bemærkelsesværdige ting han fandt var ikke et udbrud på alt-det var en stjerne som vokste mysteriously dim i flere dage i 2012. Han og hans kolleger rapporterte deres resultater i et nylig offentliggjort papir i Monthly Notices of the Royal Astronomical Society .

Known as VVV-WIT-07, the star appears to be much older and more resilient than our sun, although the amount of interstellar dust between our solar system and the star’s home closer to the galactic center makes exact classification and distance measurements very difficult. What’s certain is that the object’s brightness faded slightly for 11 days, then plummeted over the following 48 days, suggesting that something blocked more than three quarters of the star’s light streaming toward Earth. But what could that be “something”?

According to Eric Mamajek, an astrophysicist at the University of Rochester unaffiliated with the VVV survey, such a profound degree of dimming suggests that a staggeringly large object or group of objects is blocking the light . “It’s got to be over a million kilometers wide, and very close to being able to block that much starlight,” he says. Mamajek should know: He led the team that discovered J1407, another strange star periodically eclipsed by a planet-sized object thought to boast a massive ring system some 200 times broader than that of Saturn. In dit laatste geval, zegt hij, de vreemde signalen van VVV-WIT-07 kunnen ontstaan ​​uit clumps of clouds of material passing between Earth and the star, though he cautioned that the data were preliminary and more observations are required.

Tabetha Boyajian agrees. Boyajian, an astronomer at Louisiana State University, was the lead author for the 2015 paper announcing the strange dimming of KIC 8462852, also known as Tabby’s Star, an unusual object first spotted by NASA’s Kepler Space Telescope. VVV-WIT-07 would have to harbor “a very peculiar kind of dust cloud to make these kinds of dips,” Boyajian says. Boyajian’s study helped spark a surge of public interest in Tabby’s Star because the star’s unusual dimming could be seen as evidence of an alien civilization building an artificial structure that soaked up the star’s light. More conventional explanations include a swarm of comets or fragments from a shattered planet, both of which would create significant clouds of dust and debris that could also occlude the star’s light. But, so far, no simple single explanation fits the complexities of the dimming seen around the star; Researchers remain stymied in their attempt to understand the true nature of the strange dimming of Tabby’s Star.

Astronomers track such dips by plotting the intensity of a star’s light over time, a figure known as a “light curve.” The light curve of J1407 shows its massive rings can occasionally block as much as about 95 percent of the star’s light, while the light curve of Tabby’s Star suggests that whatever orbits there only encompasses about 20 percent of that star’s luminous emission. That makes VVV-WIT-07 an intermediate case, Saito says. “Our object is similar in the sense that we are also trying to explain the behavior in the light curve based on material surrounding the star,” he says.

Based on their data, including follow-up observations made in 2016, Saito and his colleagues speculate that the star may continue to flicker into 2019, potentially displaying four additional dimming events throughout the year as the mysterious light-blocking material continues its orbit around the star. Om disse forudsigelser er båret ud, kan de være et led i at unlocking ikke bare de mysterier bag VVV-WIT-07, men også de omkringliggende Tabby’s Star.

“Efter en prøve af to, kan vi have to stjerner i stedet for at studere to try to unify a theory of what is going on, “Boyajian says. Hvis begge stellar dimmings er forårsaget af det samme naturlige proces, er det mindre sandsynligt at noe unusual er happening-like, supersized kosmiske byggeprosjekter.

Det er håp om at flere av disse peculiar flickeringstjerner kan vises i nær fremtid. Saito says that it is possible the VVV survey could discover more, although it is not optimized for identifying such systems. The Large Synoptic Survey Telescope (LSST), an 8.4-meter instrument under construction in Chile, could up turn more members of the odd collection when it starts operations in the 2020s.

“I think we’re going to start finding more objects like this in the LSST era, “Mamajek says. “We are probably going to start discovering weird variables [stars].”

For now, Saito and his colleagues plan to continue observing VVV-WIT-07 with infrared instruments on the ESO’s New Technology Telescope and the National Optical Astronomy Observatory’s Southern Astrophysical Research Telescope, both of which contributed to the team’s 2016 observations. The star’s intrinsic faintness as well as the attenuation of its light across solid galactic distances means that it is best observed at near-infrared wavelengths where interference from interstellar dust is minimal. Selv om den VVV Survey afsluttede sidste år, er en udvidet undersøgelse stadig iagttagelse af det galaktiske center og kan slå op andre eclipses savnet i de indledende observationer.

Forhåbentlig vil disse observationer gøre noget lys på hvad der forårsager den bizarre dimming of VVV-WHITE -07. “This is certainly not a common phenomenon,” Mamajek says. “I can not wait to see the future results.”


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