Aliens? Potentially. That seems to be the first place everyone's mind goes when talking about Tabby's Star. And who wouldn't? Since its discovery, the celestial anomaly has garnered a lot of attention. As you probably guessed, today we are going to look at some theories about what might be causing the anomalous behavior of Tabby's Star. However, we are getting a bit ahead of ourselves.
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 mission noticed 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.
1. Is it a swarm of comets?
This is not too crazy an idea. Astronomers have noted that a series of cometary events, which emit large amounts of dust could explain the short-term flux dips that have been seen. The general idea is that the changing brightness of KIC 8462852 could be attributed to hundreds, maybe even thousands of comets passing in front of the star. But this cannot explain the long-term dimming of the star. So, check this one out for now.
2. Could it be odd magnetic activity?
If the star's exterior is not the solution, what about the star's internal workings? Researchers have looked just into that. Researchers from the University of Illinois at Urbana-Champaign have speculated that the drastic changes in brightness could be attributed to avalanche-like magnetic activity within the star.
So, what is that exactly?
As you are probably aware, a star can undergo a significant shift in its magnetic field. We see this occur in our own Sun every eleven years. The researchers at the University of Illinois at Urbana-Champaign looked at other stars in our universe that experienced dimming events and tied those changes to the star's magnetic field. Tabby's Star could be experiencing a similar phenomenon. As stated in the study, "The star KIC8462852 (Tabby's Star) has shown anomalous drops in light flux."
"We perform a statistical analysis of the more numerous smaller dimming events by using methods found useful for avalanches in ferromagnetism and plastic flow. Scaling exponents for avalanche statistics and temporal profiles of the flux during the dimming events are close to mean-field predictions."
Add this theory to your list.
3. Would about a glitch in the instruments?
Ok, this one is not as exciting, but is plausible. What if the irregularities with KIC8462852 can be attributed to a simple malfunction in the Kepler space telescope? Some people did argue that when we first examined the anomalous behavior. However, NASA scientists would go on to rule this out as a possibility, due to the fact the data from the probe is accurate, no matter which detectors on the telescope are being used.
NASA goes into detail about this in a statement about the star stating, "First, the results are the same, regardless of which of the telescope's detectors were observing the star, ruling out a defect on the lens of the photometer, or the on-board camera. Second, the enormous drops in brightness were already visible in every single pixel attributed to this star in the Kepler images."
You can cross this theory off the list too.
4. Tabby's Star may be dying?
Another hypothesis surrounding Tabby's Star is the fact that the star may be reaching the end of its life. KIC8462852 may be an F-type star. For the uninitiated, an F-type star is a star that is just a little bit larger and warmer than our own sun and tends to have a lifespan of about 2 to 4 billion years. Tabby's Star could just be reaching the end of its life. However, NASA researchers have also crossed this idea off their list, because the star has shown no indication that it is at the end of its life. In fact, while the star is brighter, hotter and more massive than our own Sun, and gives off more than four times the light of our Sun, it is also hundreds of millions of years old and appears to be burning stably on the main sequence.
So, it seems we are getting closer to aliens.
5. What if it is just dust?
This would be a bit anticlimactic if it is the case. However, this is one of the prevailing theories used to explain the odd behavior of Tabby's Star, and there is quite a bit of data now to support this theory. Recent studies at NASA point to that. "The most recent findings, based on the new data from Spitzer and Swift, point the finger at an uneven dust cloud orbiting the star to explain the long, slow dimming of the star, which may prove related to the short dips in brightness", says NASA.
Many astrophysicists are now convinced that dust is in fact the culprit, but there is quite a bit of disagreement about where the dust may have come from. Hypotheses include interstellar dust or dust from a gas giant being devoured by the star.
6. A melting ploonet?
Nope. That is not a spelling error. Tabby's odd behavior can be attributed to the properties of a thing named "ploonet". A ploonet is an exomoon. One may be orbiting the star, and could possibly be disintegrating. A study published in 2019, in the Monthly Notices of the Royal Astronomical Society, ponders this idea. It proposes that this disintegrating ploonet could be shedding chunks of rock and debris that impair our view of KIC8462852. This could explain why the dimming is so inconsistent. Some years, the star has dimmed as much a 22 percent, while other years it has dimmed only 5 percent.
This is one of the more recent theories for the star's odd behavior.
7. Maybe it is aliens?
This theory is definitely one of the most popular and has garnered a lot of attention over the years. After all, when something happens in space that we cannot easily explain, some people will assume aliens probably had something to do with it.
The hypothesis is that some form of alien megastructure is under construction around the star, for example, a Dyson sphere. The theory states that the massive hypothetical structure would periodically block a large percentage of the star's light, and as it becomes more complete over time, the amount of light blocked would increase. The fact that the light from this star has dimmed by a significant amount of the past century could be explained by an advance in the completeness of the structure.
However, before you get your hopes up, we now know this is not the case. This is because an alien megastructure would be opaque to light. Yet, some light is getting through, it is just dimmer.
Yet this idea is still capturing imaginations and is still exciting to think about. You can easily see why it is so exciting.
What is your opinion on Tabby's Star? What is your favorite theory? For more articles on celestial oddities, be sure to take a look at our articles here.