WOH G64 - a supergiant star located in the Large Magellanic Cloud, was once considered one of the largest red supergiants with a radius more than 1,500 times the Sun's. However, observations from 2013 to 2014 recorded clear changes, as the star showed signs of transitioning to a hotter state.
A research group led by Gonzalo Muñoz-Sanchez of the Athens National Observatory believes that WOH G64 has entered a rare yellow supergiant phase. This is considered a short transition in the evolutionary process, which may occur before the star explodes into a supernova.
According to analysis, the temperature of WOH G64 increased, the size shrank to about 800 times the Sun's radius, and the atmospheric composition also changed. The research team believes that this phenomenon may be related to the star releasing matter or interacting with a companion star.
However, newer observations draw different conclusions. The research team led by Jacco van Loon and Keiichi Ohnaka discovered signs of titanium oxide in the atmosphere of WOH G64. This compound only exists in red supergiants, not suitable for the hotter state of yellow supergiants.
This discovery shows that WOH G64 may still be a red supergiant and has never actually transitioned to another stage of evolution. Scientists believe that changes in brightness and color may just be temporary phenomena, rather than signs of an evolutionary turning point.
WOH G64 is located about 160,000 light-years from Earth and is closely monitored due to its particularly large size. Such red supergiants are often unstable and can undergo strong changes in their later life.
Another hypothesis suggests that this star may exist in binary systems. Interaction between two stars can change the surrounding environment, creating confusing observational signals about its true state.
Scientists emphasize the need to continue observations to determine whether WOH G64 is entering a new stage of evolution or just undergoing natural fluctuations. Future data will help clarify the evolutionary process of giant stars in the universe.
