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The science behind the galaxy’s most mysterious star



College of Charleston


The science behind the galaxy’s most mysterious star

How our attempt to understand the universe left us more questions than answers

Bridget Ierace


NASA’s Kepler Mission, which collected data from 2009 until 2013, is responsible for the identification of 4,496 exoplanet candidates, or planets that orbit a star. Among this achievement, the data collected by the Kepler Space Telescope also brought about the discovery of the most perplexing star in modern astronomy. The behavior of this star, KIC 8462852, also known as Tabby’s Star, has been a mystery to scientists for the strange dimming patterns observed across multiple wavelengths of light.

The uniqueness of this star was first noticed by Planet Hunters, a group of citizen scientists who worked on analyzing the vast amount of data produced by the Kepler Space Telescope. Since the dimmings seen in this star are so different than those caused by exoplanets, it needed to be individually studied. Dr. Tabetha Boyajian, a College of Charleston alumna and the researcher who the star is named after, was working at Yale at the time of the discovery. In 2015, Boyajian published a paper that detailed the observations made of the star at that point and proposed several possibilities for the cause of the dimming.

The dimming observed in Tabby’s Star is puzzling to scientists because it doesn’t fit models of dimmings that have been observed by other objects around other stars. The combination of long and short term dimming patterns and differences across varying wavelengths of light make the behavior of this star unique. Using new evidence from further observations from the Swift and Spitzer missions, scientists have been working to evaluate the possible theories. A new paper published this month by astronomers at the University of Arizona provides evidence in support of a theory that circumstellar material, a ring of dust, gas, and fragments that orbit around a star, is responsible for the dimming observed from Earth. This theory is supported by the observation that infrared wavelengths of light experienced less dimming effect than ultraviolet, so any regular large object occulting, or passing in front of, the star is not responsible for the behavior because it would block all wavelengths of light. However, models of orbiting circumstellar material match the observations and is a strong possibility for an explanation of this system. It explains the long term dimming observed but more research is needed to fully explain the short term dimmings. This evidence also rules out a theory of an alien superstructure that had been publicized.

In observational science, especially astronomy, research often presents more questions than it answers. NASA’s Kepler Mission set out to search for exoplanets in a survey to help determine the overall number and characteristics of planetary systems outside of our own. At the start of this mission, scientists didn’t know that they would find anything like Tabby’s Star. Discoveries of unexpected objects in space raise new questions that we didn’t even know to ask before. Every time that scientists find something they weren’t expecting, they have to find a method to find a way to begin to understand it. The mystery Tabby’s Star demonstrates how science is a process of discovering mysterious and then making sense of them. Every step science takes to learning more about something, more questions are uncovered.

Dr. Boyajian graduated the College of Charleston as an undergraduate in 2003. As a current student, I reached out to her to ask about her experiences on our campus. When I asked how her time at the College of Charleston encouraged her interest in astronomy, Dr. Boyajian said that, “it had everything to do with my interest in astronomy. This is where I took my first astro class. It was then that my professor came up to me and asked about my major and suggested physics. I was in the program at once and even started doing research!” She also advises students to take advantage of all the events that are offered on campus.