Massive Star WOH G64's Dramatic Transformation Baffles Astronomers
Scientists observe a massive star undergoing a rapid and unexplained change.
Top Summary
- What happened: Star WOH G64, 28 times the mass of the sun, rapidly changed color from red to yellow, baffling astronomers.
- Why it matters: The observation challenges existing stellar models and provides new insights into the life cycle of massive stars.
- What changes for people: It expands our understanding of the universe and the evolution of stars significantly larger than our sun.
- Who is affected: The scientific community, particularly astronomers studying stellar evolution, and anyone interested in space exploration.
A Cosmic Rockstar's Transformation
The universe's largest stars live fast and die young, much like rock stars. WOH G64, residing in the Large Magellanic Cloud, is proving to be a cosmic enigma.
Observations over three decades reveal that this star, 28 times the mass of the sun, is behaving unlike anything seen before.
Unprecedented Color Change
In 2014, researchers observed a striking change in WOH G64's color. The star transitioned from a red supergiant to a yellow hypergiant.
This change happened quickly in cosmic terms, with no evidence of an eruption or explosion. Gonzalo Muñoz-Sanchez, lead author of the study, stated that the transition defies current stellar models.
"Typically, the evolution of a star takes place on timescales of billions of years. On human timescales, we only observe more abrupt and violent events, such as eruptions, the merger of two stars or their explosive deaths,"
Size and Scale of WOH G64
Compared to our sun, WOH G64's luminosity is about 300,000 times greater. Its diameter is approximately 1,500 times larger.
If placed where our sun is, its surface would extend between the orbits of Jupiter and Saturn.
Light would take six hours to travel around the star's surface.
A Star Nearing Its End
WOH G64 is approximately 10 million years old. The sun, in contrast, is about 4.5 billion years old and expected to live for another 5 billion years.
WOH G64 is located about 160,000 light-years from Earth.
The Fate of Massive Stars
Stars between 8 and 23 times the sun's mass are expected to become red supergiants and then explode as supernovas. However, the fate of stars between 23 and 30 times the sun's mass is less certain.
It's unclear if they explode as supernovas, collapse into black holes, or evolve into yellow hypergiants.
"Hence, WOH G64 might be the solution to this question," Muñoz-Sanchez said.
A Binary System Adds Complexity
Observations indicate that WOH G64 is part of a binary system. The star is gravitationally bound to another star.
Researchers haven't determined the size or characteristics of the companion star, but they suggest a possible merger in the future.
Hypotheses on the Transformation
Researchers have proposed several hypotheses to explain WOH G64's recent changes.
- A violent event may have turned it red before the observational data was collected.
- An interaction with its companion star may have temporarily mimicked the appearance of a red supergiant.
What to Watch Next
Further observations are needed to understand the nature of WOH G64's companion star and its potential interaction with WOH G64. Continued research on this cosmic rock star could unlock secrets about the evolution of the universe's most massive stars.