Betelgeuse, the red supergiant star that marks the armpit of Orion the Hunter, has been dramatically and mysteriously dimming for the last six months.

Some astronomers and excitable members of the public have wondered if the star is about to explode as a supernova. Others have suggested more prosaic explanations, involving long-term cycles of variability, sunspots or dust.

Now new light, so to speak, has been shed on the mystery.

Recent high-resolution photographs of the star suggest that it is changing shape, astronomers from the European Southern Observatory said in a news release on Valentine’s Day. Instead of appearing round, the star now appears squashed into an oval.

A team led by Miguel Montargès of KU Leuven in Belgium used a special camera on the Very Large Telescope of the European Southern Observatory in Chile. The camera, called Sphere, for Spectro-Polarimetric High-contrast Exoplanet Research instrument, was designed to take pictures of worlds that orbit distant suns.