Astronomers can't explain unique radio waves

Astronomers are trying to explain highly unusual radio waves detected from a nearby red dwarf star.

What happened: This past spring, Astronomers at the Arecibo Observatory in Puerto Rico observed high-frequency radio wave pulses at a rate "unlike anything they had ever observed before" coming from star Ross 128, which is about 11 light years away.

These are a few of the possible explanations, per the Atlantic:

• Solar flares, but: red dwarf flares "occur at much lower frequencies and travel in different directions than what was seen around Ross 128."
• Crossing radio signals from another object in the "telescope's field of view," but: astronomers haven't seen anything to suggest that.
• Passing satellites, but: astronomers "have never seen satellites release signals of this nature."
• Interaction with an orbiting planet, but: "no planets have ben discovered around Ross 128."
• Radio frequency interference, but: astronomers don't think that's likely.
• Aliens, but: that's the least likely possibility.