Tabby's Star

Timothy Birdnow

Here is the story of a rather peculiar star. It dims periodically (and unpredictably.) The article's "hook" is aliens, but the first thing I thought of was dust clouds.

From the article:

For the uninitiated, "Tabby's Star", also known as Boyajian's Star or KIC 8462852 is a cosmic object that is located approximately 1,500 light-years from Earth. As implied in its name, it is, in fact, a star. It has been observed since around 1890, but the name comes from the researcher,Tabetha Boyajian, an assistant professor of astrophysics at Louisiana State University in Baton Rouge, who led scientific investigations concerning the star's behavior.

What makes this star so special? NASA's Kepler missionnoticed a number of oddities in the star's behavior, chief of which is that the star exhibits a huge drop in brightness, or flux (by as much as 22%)but with no corresponding drops in infrared emissions, which has not been observed before. The dips in flux occur slowly over time, although some short-term dips have also been noted.

No other stars we have come across appear to behave this way. As Boyajian put it, "This [dimming] behavior was not something we were looking for or had trained our algorithms to find. In fact, we were first alerted to the star's unique activity by citizen scientists participating in the Planet Hunters program."

Tabby's Star has set the internet ablaze, causing wild speculation and theories that would make for excellent science fiction films. Yet, what does science have to say about Tabby's Star? In the last few years, there have been significant developments in the odd case of KIC 8462852. Today we are going to look at what researchers have to say about the oddball star.

The article discusses five possible causes of this odd behavior:

1.A comet swarm.
2. Internal magnetic activity.
3. A glitch in the instruments of the Hubble Telescope.
4. The star is dying.
5. Dust.
6. A Melting Ploonet (a term for an exomoon.)
and
7. Aliens building something big (like a Dyson sphere). I don't take that last the least bit seriously; why haven't we seen any other evidence of an alien civilization? Why no overactive radio waves?

 I disagree with the criticism of the concept though in that they say "This is because an alien megastructure would be opaque to light. Yet, some light is getting through, it is just dimmer."

Well, if you are using the science fiction idea of a Dyson Sphere. That isn't what the late Freeman Dyson (of the presigious Institute for Advanced Studies at Princeton) hypothesized.

Dyson's original argument was that a truly advanced civilization would have an exponentially-growing need for energy. After a certain point they would find it necessary to block large swaths of their sun to capture the wasted solar and magnetic energy. In his view the sphere needn't be a solid structure,  it could be discontinuous, and composed of any material. It may be opaque to some degree, if they had a need just to harness certain wavelengths of light. It is very different than the science fiction idea of a habitat that is a bubble around a star.

So, it COULD be a discontinuous structure partially blocking the sunlight. But I really doubt it.

My money is on dust. There's plenty of it around, and I suspect it's just blocking the starlight intermittently.

But it is a fun thing to speculate over.

Posted by: Timothy Birdnow at 10:19 AM | No Comments | Add Comment
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