The Transformation of WOH G64: A Stellar Change

Once upon a time in far-off space, there lived a star named WOH G64. This star, known for its size and brightness, belonged to a special group of stars called Red Supergiants (RSGs). RSGs are the cool kids of the star world because they have burned bright and big for a long time. But what happens when they get too old and think they can change their style? Spoiler alert: it's a wild ride!

#WOH G64 and its Cool Phase

WOH G64 was the star that stole the show in the Large Magellanic Cloud, a neighboring galaxy. It was huge, glowed brightly, and liked to shed a bit of material into space, making it a popular star. For years, it was a classic RSG, living its best life, enjoying the coolness of being a calm and collected star.

But something strange was brewing in the universe, and observers noticed changes in WOH G64. Imagine a star having a mid-life crisis; WOH G64 was about to hit that phase!

#The Big Change

Around 2014, WOH G64 decided it was time for a makeover. It went from being a semi-regular star to an irregular one, like changing from a predictable sitcom to a chaotic reality show. This transition was noted by astronomers who observed its brightness and colors changing, almost like watching a star go from drab to fab!

Not just that, the star began to show features typical of a different kind of star—a B[e] star, which is like the star equivalent of putting on fancy clothes and getting a stylish haircut.

#What Does This All Mean?

The changes weren't just for show. They suggested that WOH G64 was transitioning from being a mellow RSG to something more exciting, known as a Yellow Hypergiant. It was like seeing your neighbor, who used to wear sweatpants all the time, suddenly show up in a tuxedo.

The star had a secret: it was actually in a relationship with another star, a B-type companion. This made WOH G64 even more interesting. It wasn’t just a star; it was part of a stellar couple!

#The Speculation: What Happened?

The transition wasn't just a whim. Astronomers came up with several theories to explain WOH G64's change. Some suggested it might have had a dramatic encounter with its partner star, leading to an exchange of material. Others thought it could have been a wild eruption that forced it to shed its outer layers. Think of it as a star throwing a glitter bomb everywhere!

#The Eruption Theory

One idea was that WOH G64 went through an eruption—like a volcano but in space. This eruption may have caused it to lose its outer layers and emerge a different star entirely. After a long series of changes, it was perhaps ready to take on the universe in a brand new light.

#The Partner Effect

The star's companion also played a role in this transformation. In a cosmic version of "you scratch my back, I scratch yours," the two stars interacted in ways that changed WOH G64's appearance and behavior. Such relationships can lead to dramatic changes, and WOH G64 was no exception!

#Watching the Light Show

Astronomers kept a close eye on WOH G64's brightness over the years. They noticed its light fluctuated and changed color, much like how your mood can change with the season. Before 2014, it had a steady rhythm like a song on repeat, but after that, it was more like a DJ mixing tracks at a party. The star's journey was becoming more erratic and exciting!

#Mid-Infrared and Optical Light Curves

Light curves are like the mood rings of stars; they show how bright a star is over time. WOH G64 had its light curve charted out, and it told the story of a star in transformation. The observations revealed outbursts, drops in brightness, and a shift from red to a much prettier blue. It was moving toward a brighter future!

#A Spectral Spectacle

Astronomers love to examine the light from stars to find out what they're made of and how they're changing. They took special pictures—spectra—of WOH G64, catching all the colorful details. The findings showed that the star had lost some of its classic features. The deep, dark bands typical of an RSG were disappearing, and bright emissions were taking over, signaling it was on the road to becoming a B[e] star.

#The Clarity of Change

In the years leading to 2016 and beyond, the spectral characteristics grew more pronounced. Instead of showing clear signs of being a late M-type star, WOH G64 started to show features typical of hotter, more dynamic stars. The transformation was remarkable, like turning from a couch potato into a star athlete!

#Theoretical Scenarios for the Change

Astronomers love their theories, and WOH G64 was no different! They came up with several scenarios to make sense of all these changes. Each hypothesis painted a different picture for what could have occurred to this marvelous star.

#Pre-Supernova Winds

Some proposed that WOH G64 may have been in an intense pre-supernova wind phase, shedding its outer layers in a slow but steady manner. This gradual process could lead to a warmer star, pushing it out of the RSG stage and into the YHG category.

#Interaction in a Binary System

Others believed that the interaction with its B-type companion caused this unique change. If WOH G64 was in a close binary system, the gravitational pull from the companion could have been the trigger for this transformation.

#Eruptions and Outbursts

The possibility of a significant eruption was also a prime suspect. A strong outburst might have erupted from WOH G64, ejecting material and altering the star's makeup. This scenario has parallels to other stars that have undergone dramatic changes due to eruptions.

#A Cosmic Mystery

Despite the various insights, a clear picture of WOH G64’s journey is still a mystery. There’s no one-size-fits-all explanation, and that’s what makes stellar evolution so intriguing! WOH G64 keeps the secrets of its transformation close, waiting for the right astronomer to unveil them.

#Conclusion

In the grand stage of the universe, WOH G64's transformation from a Red Supergiant to a Yellow Hypergiant highlights the incredible journeys that stars can take. It's a reminder that even in space, change is the only constant.

As astronomers continue to watch WOH G64, they are keenly aware that this star has a lot more surprises in store. After all, even stars love to keep their audience guessing!