from the just-needs-a-bit-of-swiffering dept.
Tabby's star, aka KIC 8462852, is likely surrounded by orbiting dust grains that block ultraviolet light:
The bizarre long-term dimming of Tabby's star—also known as Boyajian's star, or, more formally, KIC 8462852—is likely caused by dust, not a giant network of solar panels or any other "megastructure" built by advanced aliens, a new study suggests.
Astronomers came to this conclusion after noticing that this dimming was more pronounced in ultraviolet (UV) than infrared light. Any object bigger than a dust grain would cause uniform dimming across all wavelengths, study team members said.
"This pretty much rules out the alien megastructure theory, as that could not explain the wavelength-dependent dimming," lead author Huan Meng of the University of Arizona said in a statement. "We suspect, instead, there is a cloud of dust orbiting the star with a roughly 700-day orbital period."
Aliens left to roam free once again.
Previously: Tabby's Star Under Observation After Dimming Event Detected
Tabby's Star Dimming Could be Explained by a Saturn-Like Exoplanet
Extinction and the Dimming of KIC 8462852 (DOI: 10.3847/1538-4357/aa899c) (DX) (arXiv)
Related Stories
Tabby's Star, speculated to be surrounded by a cloud of debris or alien megastructures, has dimmed yet again, causing multiple observatories to take notice:
Among the telescopes [Jason] Wright said researchers now hope to use to catch this dimming event in the act:
—The Green Bank Telescope in West Virginia, the world's largest fully steerable radio telescope
—The Automated Planet Finder at Lick Observatory near San Jose, Calif., a robotic optical telescope
—Both telescopes at the Keck Observatory in Hawaii, which operate in optical and near-infrared wavelengths
—The MMT Observatory in Arizona, an optical telescope
—NASA's Swift Gamma-Ray Burst Mission, which operates in gamma ray, x-ray, ultraviolet and optical wavelengths
—Las Cumbres Observatory, a worldwide network of robotic optical telescopes
—Fairborn Observatory in Arizona, which operates in optical wavelengths
—The Large Binocular Telescope in Arizona, which operates in optical and near-infrared wavelengths
—The Hobby–Eberly Telescope in Texas, an optical telescope
Also at The Verge.
One astronomer has proposed looking at the nearest 43 to 85 pulsars for megastructures (arXiv):
Osmanov estimates that the habitable zone around a relatively slowly-rotating pulsar (with a period of about half a second) would be on the order of 0.1 AU. According to his calculations, a ring-like megastructure that orbited a pulsar at this distance would emit temperatures on the order of 390 K (116.85 °C; 242.33 °F), which means that the megastructure would be visible in the IR band.
Previously: Mysterious Star May Be Orbited by Alien Megastructures
I'm STILL Not Sayin' Aliens. but This Star is Really Weird.
"Breakthrough Listen" to Search for Alien Radio Transmissions Near Tabby's Star
Non-Alien Explanation for Tabby's Star Dimming: It Ate a Planet
Rather than debris or alien megastructures, Tabby's star may host a Saturn-like exoplanet:
The "alien megastructure" star that has been puzzling us for the past few years might have a more ordinary explanation: an orbiting Saturn-like planet, complete with wobbling rings. [...] Speculation abounded, with explanations ranging from exoplanetary comets to a vast orbiting "megastructure" built by an advanced alien civilisation.
Now Mario Sucerquia and his colleagues at the University of Antioquia in Colombia have proposed another possibility: a ringed planet, similar to Saturn, orbiting close to the star. Such a planet would dim the star's light in an irregular way during a transit.
First, the rings would block some of the star's light, followed by the planet, which would dim it further. Then, after the planet passes, the rings would block some light again. But because the rings would be at a different angle each time, the small dips at the beginning and end of the transits would be larger or smaller. Without seeing many transits, there would be no obvious pattern to this.
"Saturn-like" can mean a variety of things for the hypothetical object. For example, the rings of 1SWASP J1407b are about 200 times the diameter of the rings of Saturn.
Anomalous lightcurves of young tilted exorings
Related paper: KIC 8462852: Will the Trojans return in 2021?
Previously: Tabby's Star Under Observation After Dimming Event Detected
The dips in brightness observed at Tabby's star are still probably caused by dust, and not alien megastructures:
For the last two years, astronomers all over the world have been eagerly observing what is hailed as "the most mysterious star in the Universe," a stellar object that wildly fluctuates in brightness with no discernible pattern — and now they may finally have an answer for its weird behavior. Scientists are fairly certain that a bunch of dust surrounding the star is to blame. And that means that the more tantalizing explanation — alien involvement — is definitely not the cause.
It's the most solid solution yet that astronomers have come up with for this star's odd ways. Named KIC 8462852, the star doesn't act like any star we've ever seen before. Its light fluctuations are extreme, dimming by up to 20 percent at times. And its dips don't seem to repeat in a predictable way. That means something really big and irregular is passing in front of this star, leading scientists to suggest a number of possible objects that could be blocking the star's light — from a family of large comets to even "alien megastructures" orbiting the star.
Also at Sky & Telescope and Discover Magazine.
(Score: 3, Informative) by Anonymous Coward on Friday October 06 2017, @08:53PM
We all know the truth. It's a vastly more advanced civilization with a Dyson structure around that star.
But the violent, authoritarian left doesn't want you to know about it because the only way to achieve such heights as a civilization is through Capitalism and the Free Market™!
In fact, I have it on good authority that the Clintons have dispatched one of their evil death squads from 100 Broad Street to nuke those freedom loving aliens so their authoritarian communist agenda won't be thwarted.
#MAGA
(Score: 3, Funny) by Grishnakh on Friday October 06 2017, @09:18PM (3 children)
This means that there isn't a functioning Dyson swarm or other megastructure around this star. Instead, it means there was a megastructure, and it's been obliterated, and the dust cloud from this is causing the effect we see.
We're too late.
(Score: 5, Insightful) by richtopia on Friday October 06 2017, @10:17PM (1 child)
Incorrect. This is actually a nanobot swarm functioning as a dyson sphere.
(Score: 2) by Grishnakh on Friday October 06 2017, @11:11PM
Aha! Excellent insight!
(Score: 0) by Anonymous Coward on Friday October 06 2017, @10:56PM
Are we now?
What if they determined they wanted to limit the information leakage of their civilization, as they determined it would be best to see the other races first and not second?
It may just be tactical deception
(Score: 5, Interesting) by PinkyGigglebrain on Friday October 06 2017, @10:34PM
isn't UV the ideal spectrum range for solar cells? High energy, readily knocks electrons loose from atoms and is abundant in the light output of most main sequence stars.
And even the article mentions that dust doesn't explain all the other weird stuff they have observed.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 0) by Anonymous Coward on Friday October 06 2017, @11:54PM
How did they distinguish between dust and nanomachines?
(Score: 2) by Snotnose on Saturday October 07 2017, @01:14AM
Dust between us and the aliens (unlikely), or dust ingested by the scientists studying it (also unlikely).
Wat do? Wat think? Who trust? Brain dead enquiring minds want to know!
When the dust settled America realized it was saved by a porn star.
(Score: 2) by looorg on Saturday October 07 2017, @01:19AM (1 child)
But where did all the dust come from? A dust cloud with a 700-day orbital period sounds kinda large, is this the cloud of dust left behind from the Aliens firing their Planetbuster-death-ray-cannon? We saw what happened to Alderaan ...
(Score: 0) by Anonymous Coward on Saturday October 07 2017, @04:23AM
A 700 day orbit is about the equivalent of Mars orbit. Seems very unlikely dust would be stable. Should either coalesce or be dispersed by stellar wind.
(Score: 2) by krishnoid on Saturday October 07 2017, @06:53PM
I think that before (or along with) a scientist being allowed to publish something that shuts down an interesting theory with a boring fact, they should have to write a short sci-fi story based on the interesting theory. I bet it would make people feel a little better about science in general [kickstarter.com]. Maybe (long-shot) it could even ameliorate the bias towards sensationalistic science reporting a little.