Mary Bowerman

USA TODAY Network

A mysterious star that some astronomers believe could harbor an "alien megastructure,” continues to confound researchers.

A study accepted for publication in the Astrophysical Journal has only “deepened the mystery” surrounding the strange light pattern emitted from the star known as KIC 8462852.

Josh Simon of the Carnegie Institute and Ben Montet of Caltech analyzed data gathered by the Kepler space telescope during the four-year period the telescope observed KIC 8462852, Carnegie Science said in a statement.

The star is one of some 160,000 stars that NASA's Kepler Space Telescope has spotted since 2009, though its unusual light pattern captured the attention of many.

Kepler hunts for Earth-like planets in the Milky Way Galaxy by measuring the brightness of stars and looking for tiny dips in light patterns that could signify an orbiting planet. In most cases, when a planet is orbiting a star the Kepler measures a uniform light pattern.

However, the strange dimming of KIC 8462852 suggests a large mass of matter is circling KIC 8462852. Over the past year, scientists have hypothesized that everything from a mass of comets to bad data or alien structures could be to blame for the unusual light curve. So far, nothing has been conclusive and attempts to identify radio signals from the star have been unfruitful.

Search for 'alien megastructure' on distant star underway

Montet and Simon investigated the star's light pattern through a series of Kepler calibration images that had not yet been used for scientific measurements, according to Carnegie.

“We thought that these data could confirm or refute the star’s long-term fading, and hopefully clarify what was causing the extraordinary dimming events observed in KIC 8462852,” Simon said in a statement.

The researchers found over the first three years of Kepler’s mission, the star dimmed just 1%. The light from the star then dimmed 2% over six months and remained at the level for the remainder of Kepler’s mission.

After comparing the star's light pattern to 500 similar stars observed by Kepler, the researchers found that the fading KIC 8462852 displayed over the first three years wasn’t uncommon. What stood out, was that none of the other stars exhibited the heightened dimming that KIC 8462852 exhibited over the final six month period.

“The steady brightness change in KIC 8462852 is pretty astounding,” Montet said. “Our highly accurate measurements over four years demonstrate that the star really is getting fainter with time. It is unprecedented for this type of star to slowly fade for years, and we don’t see anything else like it in the Kepler data.”