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Boyajian's Star ("Tabby's Star"): Odd Dimming; Alien Megastructure?

Vardoger

Vardoger

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Alien megastructure' could surround giant star baffling scientists looking for new planets

When planet spotters studied KIC 8462852 they noticed a swarm of objects surrounding it in an usual pattern

A series of mysterious objects surrounding a giant star millions of miles away could be an alien megastructure, experts believe.

Planet spotters examining data from the Kepler Space Telescope were startled by an unusual light pattern orbiting a star called KIC 8462852.

When they studied the star, which sits some 1,480 light years from Earth, they noticed a swarm of objects surrounding it in an usual pattern.


At first it was thought to be comets, shrapnel from an asteroid impact or even a mistake in the data.

But astronomer Jason Wright from Penn State University offered a more science fiction explanation.

He believes it could be an 'alien megastructure' designed to harness energy from the star.

He said: "Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build."

Tabetha Boyajian oversees Planet Hunters , a program that asked 'citizen scientists' to examine light patterns emitted by stars from their homes.

Etc.

http://www.mirror.co.uk/news/world-news/alien-megastructure-could-surround-giant-6632574
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kic_8462852.jpg
 
SameOldVardoger said:
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A star called KIC 8462852 has been in the news recently for unexplained and bizarre behavior. NASA's Kepler mission had monitored the star for four years, observing two unusual incidents, in 2011 and 2013, when the star's light dimmed in dramatic, never-before-seen ways. Something had passed in front of the star and blocked its light, but what?

Scientists first reported the findings in September, suggesting a family of comets as the most likely explanation. Other cited causes included fragments of planets and asteroids.

A new study using data from NASA's Spitzer Space Telescope addresses the mystery, finding more evidence for the scenario involving a swarm of comets. The study, led by Massimo Marengo of Iowa State University, Ames, is accepted for publication in the Astrophysical Journal Letters. ...

http://www.nasa.gov/feature/jpl/strange-star-likely-swarmed-by-comets

:cry:
 
The 'aliens' explanation may be back on the table:

https://www.newscientist.com/articl...ain-weird-alien-megastructure-star-after-all/

Comets can’t explain weird ‘alien megastructure’ star after all
The weirdest star in the cosmos just got a lot weirder. And yes, it might be aliens.

Known as KIC 8462852, or Tabby’s star, it has been baffling astronomers for the past few months after a team of researchers noticed its light seemed to be dipping in brightness in bizarre ways. Proposed explanations ranged from a cloud of comets to orbiting “alien megastructures”.

Now an analysis of historical observations reveals the star has been gradually dimming for over a century, leaving everyone scratching their heads as to the cause.
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Rest of article at link.
 
I do find this quite exciting. The light curves of millions of stars have been examined and this is the only one exhibiting this behaviour. If intelligent life is very rare and tends to be confined to single systems, this is exactly the sort of thing I'd expect to see.
 
Except that if this were a dyson sphere under construction we should see a lot more waste heat, but the infra-red emissions seem to be normal. It almost seems like they are turning down the star, somehow.
 
Well, in proper a Sherlockian (assuming that's a word) manner, they are eliminating possibilities.

/hopefully leaving aliens.
 
eburacum said:
Except that if this were a dyson sphere under construction we should see a lot more waste heat, but the infra-red emissions seem to be normal. It almost seems like they are turning down the star, somehow.
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Could they be hiding the infra-red emissions somehow? I mean a civilization might not want to advertise itself to the universe out of concern that a more advanced civilization might find them. A few hundred year period of being detectable by light might be considered acceptable for the energy benefits of a dyson sphere if you could mitigate detection by other methods over the longer term.
 
There are two possible ways of hiding their infrared emissions that I can think of, and neither of them are very easy.
1/ they could use technology to convert light directly into matter. As you know, energy and matter are equivalent, and in theory light could be converted into mass according to E=MC2. This would reduce the luminosity of the star. But every method we know of converting light into mass is very, very, very inefficient, and would kick out loads of waste heat. So barring some Xeelee-level tech, I think that's a non-starter.
2/ they could increase the area of the radiating surface until it was very, very cool, near the cosmic microwave temperature. This would need a sphere tens of Astronomical Units in radius. Not impossible, but a lot of bother to make something invisible.

A third option would be some kind of I-R mirror directing the light away from us; that would work, but it would make them more detectable in some other direction.
 
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http://arxiv.org/abs/1601.07314
KIC 8462852 did likely not fade during the last 100 years
Michael Hippke, Daniel Angerhausen
(Submitted on 27 Jan 2016)
A recent analysis found a "completely unprecedented" dimming of 0.165±0.013 magnitudes per century in the F3 main sequence star KIC8462852. This star is interesting, as it shows episodes of day-long dips with up to 20% dimming of unknown origin. We re-analyze the same Harvard archival Johnson B photometry and find comparable dimmings, and structural breaks, for 18 of 28 checked F-dwards (64%) in the Kepler field of view. We conclude that the Harvard plates photometry suffers from imperfect long-term (1890--1989) calibration. The most likely explanation for the century-long dimming of KIC8462852 is thus a data artefact, and it is probably not of astrophysical origin.

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Science - always changing its mind...
 
And a response by Bradley Schaefer to Michael Lipke's paper (previous post)

http://www.centauri-dreams.org/?p=34933
If there were any systematic problems for the DASCH data with Tabby’s star, then we should see the exact same dimming trend in the check stars as is seen for Tabby’s Star. But we do not. These ‘check stars’ serve as the classic control study in science. They serve as proof that neither the check stars nor Tabby’s Star have any substantial systematic problem. They serve as proof that Hippke’s title is wrong.
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More on the splendidly bizarre Tabby's Star, which just keeps getting weirder:

You know this star: It undergoes very odd dips in brightness that have defied explanation. The star, formally called KIC 8462852 (but nicknamed Tabby’s Star after Tabetha Boyajian, the astronomer who led the team investigating it), has been observed by the Kepler spacecraft for some time now. Kepler looks for dips in brightness in stars indicating the presence of a planet orbiting it; the planet blocks a tiny bit of star light, and that drop in brightness can be detected.

But Tabby’s Star isn’t behaving itself. Instead of a smooth dip and subsequent rise in brightness indicating a planet, it suffers nonperiodic, asymmetric, and very deep dips in brightness. This is not at all what you expect from a planet. Ideas including shattered asteroids and swarms of comets explain some but not all of the dips.
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Then an announcement was made that over the past century or more the star has been fading at an unprecedented rate. This finding was immediately called into question, though, and the issue of fading remained unresolved.

But now a new study, using data from Kepler itself, shows that Tabby’s Star really is fading, and at quite a clip: Over three years of observation it faded by nearly 1 percent, then took a sudden nosedive, fading by two percent in the next 200 days.
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Well worth reading the whole thing, as there doesn't seem to be any clear explanation for what's happening, and as Mr Plait sums it up:

The only thing we know for sure is that we haven’t ever seen anything like this before, and that we are seeing is really, really weird.
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Phil Plait's Bad Atronomy
 
You're probably all too familiar with the story of KIC 8462852, a star that's been the focus of much speculation and excitement over the past few months.

KIC 8462852 was observed by NASA's Kepler mission and has become infamous for its bizarre and unprecedented transit signal that was flagged by citizen scientists. Now new research of precision Kepler observations has shown that the overall brightness of the star — unofficially named "Tabby's Star" after astronomer Tabetha S. Boyajian who discovered the peculiar signal — has been decreasing, which poses a new and confusing problem for astronomers trying to understand what the heck is going on.

RELATED: Kepler's 'Bizarre' Signal Sparks Alien Intelligence Speculation

Kepler's prime mission is to look for small worlds that pass in front of their parent stars causing a slight dimming of starlight. The "transit method" has been hugely successful and has confirmed well over 2,000 planets orbiting other stars in our galaxy.

But Tabby's Star's transit signal, otherwise known as a "light-curve", stopped astronomers in their tracks. Something passed in front of it, dimming its starlight a whopping 20 percent and other jumbled transit signals revealed that something wasn't quite right with this particular star. Then, in an interview with The Atlantic, Penn State University astronomer Jason Wright speculated that the signal could be indicative of an "alien megastructure" that's in the process of being built. You can catch up on the controversy surrounding the anomalous signal in my recent Discovery News article "Closing In on 'Alien Megastructure' Clues." ...

http://www.space.com/33674-alien-me...aign=socialtwitterspc&cmpid=social_spc_514648
 
kamalktk said:
Since I helped fund the recent kickstarter to study Tabby's Star. I want to say woooooohhh! :D
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We could name the alien race after you, but I'm not sure how to pronounce your name.
 
PeteByrdie said:
We could name the alien race after you, but I'm not sure how to pronounce your name.
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Kamal, the rest are some random letters I typed in long ago on some board because kamal is normally already taken.

I'd vote for the Tabbys or Tabethans as the hypothetical race's name.
 
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kamalktk said:
Kamal, the rest are some random letters I typed in long ago on some board because kamal is normally already taken.

I'd vote for the Tabbys or Tabethans as the hypothetical race's name.
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Still, the Kamaltoes has a ring to it.
 
Plausibility of Dyson spheres/swarms, and laternatives:


I can't help thinking that if a Dyson swarm would be detectable from some distance acros the galaxy... that might be a good reason not to build one!
 
OneWingedBird said:
Plausibility of Dyson spheres/swarms, and laternatives:


I can't help thinking that if a Dyson swarm would be detectable from some distance acros the galaxy... that might be a good reason not to build one!
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If we could build one, we'd be much better positioned to defend against someone that could detect one. After all, we could theoretically detect one, but we are no threat to the builders. On the other hand, given the technology required to build one, they could probably detect us already.
 
Dunno. I think that could go either way. Assuming the time/distance factor makes it viable to have a go on an interstellar scale.
 
OneWingedBird said:
Plausibility of Dyson spheres/swarms, and laternatives:


I can't help thinking that if a Dyson swarm would be detectable from some distance acros the galaxy... that might be a good reason not to build one!
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Tabby's Star?
 
rynner2 said:
Can't see it. It doesn't like my Adblock, and I'm not going in on Google or Facebook.
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The theory is that the star has a protoplanetary dust cloud which is causing the variation in brightness.
 
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