Researchers have uncovered a new type of pulsating star that's taken on a teardrop shape as it becomes affected by a nearby star's gravitational pull, according to Pennsylvania State University.

It has traditionally been thought that pulses on stars occur on all sides, but the newly discovered star exhibited an unusual single-sided pulsation. Researchers believe it's caused by the gravitational pull of its close companion star distorting the oscillations, Penn State said in a release Monday.

"Since the 1980s, we've believed that systems like this could exist, but it is only now that we have finally found one," said Don Kurtz, a professor at the University of Central Lancashire in the United Kingdom and a co-author of the findings.

The university's team of astronomers, who published their findings in Nature Astronomy, were tipped off by "citizen" astronomers.

"Stars that pulsate have been known in astronomy for a long time," said Zhao Guo, a researcher at Penn State and an author of the paper. "The rhythmic pulsations of the stellar surface occur in young and in old stars, can have long or short periods, a wide range of strengths, and different causes. There is however one thing that, until now, all of these stars had in common: The oscillations were always visible on all sides of the star."