Tag Archives: Tabby’s Star

Another star found that dims strangely like Tabby’s Star

Astronomers have found a second star that dims in an inexplicable manner, like Tabby’s Star.

Known as VVV-WIT-07, the star appears to be much older and redder 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 is certain is that in the summer of 2012, 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 “something” be?

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 dense to be 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 this latest case, he says, the strange signals from VVV-WIT-07 could arise from clumps or 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 attempts to understand the true nature of the strange dimming of Tabby’s Star.

As is usually the case in these cases, the explanation will not be aliens. That it could be, however, is what makes it so intriguing.

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The mysterious dust surrounding Tabby’s Star

New studies of Tabby’s Star suggest that the dust clouds that cause it to fluctuate in brightness in apparently random ways are unusual and baffling in their own right.

[I]t appears that the dimming of Tabby’s star comes not from large objects such as swarms of asteroids, comets, or alien solar collectors, but from drifting bands of dust particles. But like any good mystery, it’s not quite that simple.

Each of the four dimming events observed in 2017 affected red and blue light differently, suggesting that they involved dust particles of different sizes. And the long-term brightness changes appear to be associated with much larger grains. “So the dust cloud is extremely complex,” Bodman says. “Each dip is a different kind of dust … What we’re seeing is different parts of the [dust] cloud as they pass in front of the star.”

A first guess, probably wrong, is that the four dimming events were caused by dust streams orbiting the star at different distances, each a different patchy ring around the star made up of slightly different materials.

And if you accept my guess as right, I also have bridge in Brooklyn I want to sell you. Real cheap too!

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Tabby’s Star dims again

Scientists studying Tabby’s Star have revealed that it suddenly dimmed last week, the most since 2013, and then just as quickly returned almost to normal.

The latest dimming event started with a slow decline and ended with a rapid increase in brightness, Boyajian and her team wrote on their blog. Dust from a backward comet tail and then larger chunks from the broken-up body would explain that uneven pattern.

At this time the evidence clearly points not to alien megastructures but to clouds of fine dust whose structure and origin remain puzzling.

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New data from Tabby’s Star suggests that dust, not alien megastructures, is the cause of its dimming

New observations of Tabby’s Star now suggests that it is dust, not alien megastructures, that has caused the star’s erratic fluctuations in dimming over the past century.

“Dust is most likely the reason why the star’s light appears to dim and brighten. The new data shows that different colors of light are being blocked at different intensities. Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure,” said [LSU Department of Physics & Astronomy Assistant Professor Tabetha Boyajian].

Though the data appears strong, it still leaves astronomers a bit baffled about how dust could cause the particular dimming they have seen.

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More strange behavior from Tabby’s Star

Astronomers reviewing past data of KIC 8462852, known as Tabby’s Star to the public, have discovered that not only has it been dimming in a variety of inexplicable ways, it also has brightened twice in a manner that eliminates all past theories for its behavior, including alien megastructures.

The latest findings from Carnegie’s Josh Simon and Benjamin Shappee and collaborators take a longer look at the star, going back to 2006—before its strange behavior was detected by Kepler. Astronomers had thought that the star was only getting fainter with time, but the new study shows that it also brightened significantly in 2007 and 2014. These unexpected episodes complicate or rule out nearly all the proposed ideas to explain the star’s observed strangeness.

Up until now, all the changes to the star had involved dimming, though in ways that did not fit any present theory of stellar evolution. Thus, astronomers theorized that the dimming was caused by something moving in front of the star, from comets to dust to alien structures. This new data of two significant brightening events makes all those theories invalid.

Update: More news about Tabby’s Star: Using two space telescopes as well as amateur telescopes on the ground scientists have determined that the dimming must come from an uneven dust cloud.

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Tabby’s Star is dimming again and astronomers are rushing to watch

The uncertainty of science: Astronomers today have noticed that Tabby’s Star has begun to dim precipitously again, and have put out a call for people to observe it.

No one still has a good theory to explain the star’s light changes, so having the chance to gather data throughout an entire dimming cycle will be invaluable.

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Could Tabby’s Star have eaten a planet?

A new theory has been proposed by astronomers to explain the unprecedented dimming of Tabby’s Star, and it isn’t an alien civilization.

If Tabby’s star devoured a planet in the past, the planet’s energy would have made the star temporarily brighten, then gradually dim to its original state. The bigger the planet was, the longer the star would take to dim. Depending on the size of the planet, this event could have happened anywhere between 200 and 10,000 years ago.

As the planet fell into its star, it could have been ripped apart or had its moons stripped away, leaving clouds of debris orbiting the star in eccentric orbits. Every time the debris passes between us and the star, it would block some light, making the star seem to blink.

If true, this theory would suggest that such events can happen more than scientists has expected. Moreover, this theory can be tested during future observations when the star experiences its next dimming.

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Computer modeling suggests light fluctuations at Tabby’s Star are natural

A computer analysis of the light fluctuations of Tabby’s Star suggest to astronomers that the changes are not caused by objects blocking the star (such as an alien Dyson Sphere under construction) but are instead natural variations caused as the star evolves.

This conclusion is decidedly uncertain. They do not know the nature of this stellar evolution. And they are applying avalanche models to the star to come to this conclusion.

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Aggressive SETI observations of Tabby’s star upcoming

Breakthrough Listen, an effort to listen for radio signals from alien civilizations that, plans to devote significant time this year observing Tabby’s star to see if an alien mega-structures are causing that star’s unexplained dimming.

While Siemion and his colleagues are skeptical that the star’s unique behavior is a sign of an advanced civilization, they can’t not take a look. They’ve teamed up with UC Berkeley visiting astronomer Jason Wright and Tabetha Boyajian, the assistant professor of physics and astronomy at Louisiana State University for whom the star is named, to observe the star with state-of-the-art instruments the Breakthrough Listen team recently mounted on the 100-meter telescope. Wright is at the Center for Exoplanets and Habitable Worlds at Pennsylvania State University.

The observations are scheduled for eight hours per night for three nights over the next two months, starting Wednesday evening, Oct. 26. Siemion, Wright and Boyajian are traveling to the Green Bank Observatory in rural West Virginia to start the observations, and expect to gather around 1 petabyte of data over hundreds of millions of individual radio channels.

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The mystery of Tabby’s Star deepens

The uncertainty of science: New data from Kepler has made it even more difficult for scientists to explain the strange fluctuations and dimming of Tabby’s Star.

KIC 8462852, as it is more properly known, flickers so erratically that one astronomer has speculated that nothing other than a massive extraterrestrial construction project could explain its weird behaviour. A further look showed it has been fading for a century. Now, fresh analysis suggests the star has also dimmed more rapidly over the past four years – only adding to the enigma. “It seems that every time someone looks at the star, it gets weirder and weirder,” says Benjamin Montet at the California Institute of Technology, who led the study.

There are as yet no natural explanations for the star’s dimming.

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New analysis says it ain’t aliens at strange star

The uncertainty of science: A new analysis of old star data has concluded that KIC 8462852, also known Tabby’s Star and subject to random fluctuations that no scientist can explain, has not dimmed by 20% in the past century.

This reduces the chances that the fluctuations are caused by the slow accumulating construction of a Dyson sphere by an alien civilization, as some have proposed, but it still does nothing to explain the star’s random changes in brightness.

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