A groundbreaking achievement was recently marked by astronomers who captured the first close-up image of a star from beyond our Milky Way galaxy. This star, known as WOH G64, is located about 160,000 light-years away in the Large Magellanic Cloud, one of the smaller galaxies orbiting our own. The image shows WOH G64 enveloped in what appears to be an egg-shaped cocoon, marking the end stages of its stellar life.
Details of this remarkable discovery were published last week in the paper, titled Imaging the Innermost Circumstellar Environment of the Red Supergiant WOH G64 in the Large Magellanic Cloud, appearing in the journal Astronomy and Astrophysics. This achievement is significant as it provides the first detailed view of the processes occurring around such massive stars as they approach supernova events.
Before this feat, capturing images of stars outside the Milky Way had only resulted in pictures appearing as mere points of light. The new image of WOH G64 was made possible thanks to the European Southern Observatory’s Very Large Telescope Interferometer (VLTI). This advanced instrument operates by combining light from four telescopes each measuring eight meters across, amplifying the resolution significantly to create detailed images.
Lead author Keiichi Ohnaka, from Universidad Andrés Bello, remarked, "For the first time, we have succeeded in taking a zoomed-in image of a dying star outside our own Milky Way." This was echoed by fellow researcher Gerd Weigelt from the Max Planck Institute for Radio Astronomy, who added, "We have found the star has been experiencing significant changes over the last ten years, granting us rare insight to witness stellar life cycles in real-time."
WOH G64 is one of the largest stars known, estimated to be approximately 2,000 times larger than our Sun. The new images depict the star shedding its outer layers, resulting in arcs and wreaths of dust and gas around it. It is well understood among astronomers this size and behavior suggest WOH G64 is nearing the end of its life.
Dr. Jacco van Loon, also part of the research team, highlighted the immense energy massive stars expend just before they explode. He stated, “Massive stars explode with energy equivalent to the Sun shining for all of its 10 billion years of life.” This explosion can lead to the formation of black holes or supernovae, which play significant roles in distributing elements throughout the universe, including those forming planets and life.
The capturing of WOH G64's image is especially significant as it showcases the outer layer is gradually being expelled. Citing the findings, Dr. van Loon mentioned how astronomers have witnessed the aftermath of supernova explosions but had seldom observed a star’s transformation signaling inevitable collapse. “This is the first time we’ve seen the process changing,” he added.
The image reveals not only the dramatic cocoons of gas and dust surrounding the star but also raises questions about why the cocoon appears elongated, differing from the expectations based on previous models. Astronomers speculate it could result from the star's rotation or due to interactions with its surroundings.
Scientists have long asserted the importance of studying these massive stars, primarily to understand how they evolve and influence their surrounding environments. The newly collected data from WOH G64 provides unprecedented layers of insight, potentially changing how astronomers view massive star dynamics and their eventual supernova events.
For the first time, researchers have glimpsed such complexity around WOH G64, making this not only a significant milestone but also paving the way for future research on other stars alike. Observatories will likely utilize what's learned from this momentous photograph to improve our knowledge of the life cycles of stars across the universe.
While the findings develop, astronomers recognize the challenge at hand: WOH G64 has been dimming over the last decade. This decline may pose difficulties for future studies, yet the wealth of detail gained from this image cements its importance.
Dr. Ohnaka concluded with optimism, noting the advancement of telescope technology has opened new horizons. “It’s remarkable to reflect on how far we've progressed; we're now witnessing, almost at the edge of the universe, the last embers of these magnificent stars.” Each new discovery adds another piece to the grand puzzle of our cosmos, inviting endless curiosity and exploration of the universe.
