James Webb Could Change Our Understanding of Stellar Evolution

NASA's James Webb Space Telescope has turned the tables on our understanding of a groundbreaking cosmic event—the first-ever observation of a star consuming a planet. Groundbreaking findings published in The Astrophysical Journal reveal that this star didn't just swell up to envelop a planet as previously believed. Instead, it appears the planet spiraled ever closer to its doom, leading to its tragic engulfment.

Lead author Ryan Lau, an astronomer at NSF NOIRLab in Tucson, Arizona, stated, "Given the novelty of this event, we had no idea what results to expect when we aimed the telescope at it. With its high-resolution infrared capabilities, we are uncovering vital insights into the ultimate fates of planetary systems, which could include our own future!"

A Mystery in the Milky Way

Situated about 12,000 light-years away in the Milky Way galaxy, this star, designated ZTF SLRN-2020, was initially spotted as a flash of light by the Zwicky Transient Facility in San Diego. However, additional data from NASA's NEOWISE revealed it had begun to brighten in infrared wavelengths a year prior, suggesting the presence of dust and a more complicated story behind the stellar event.

Webb's Instruments Unveil the Truth

Using Webb's MIRI and NIRSpec instruments, researchers adopted a dual investigative approach to dissect the cosmic drama. While they initially thought the star was sun-like and transitioning into a red giant, Webb’s observations contradicted this. The light revealed it wasn't as bright as a typical red giant should be, meaning it hadn't swollen to engulf its planetary victim.

A Planet's Deadly Dance

Researchers speculate that the doomed planet—once about the size of Jupiter—orbited alarmingly close to the star, even closer than Mercury does to our Sun. Over millions of years, its orbit inched closer, leading to an inevitable catastrophe.

"The planet grazed the star's atmosphere, initiating a rapid descent into oblivion," explained Morgan MacLeod from Harvard-Smithsonian and MIT. "As it fell, the planet began to smear out around the star, disturbing the cosmic equilibrium!"

What Came Next?

The planet's last moments were explosive, blasting gas from the star's outer layers. In the aftermath, this gas cooled and condensed into dust over the subsequent year.

However, NIRSpec uncovered something unexpected: a hot ring of molecular gas around the star—akin to a planet-forming region, even though no new planets are being formed there now. This revelation raises further questions about the conditions in this newly transformed environment.

A New Frontier in Astronomy

Colette Salyk, a co-author and exoplanet researcher at Vassar College, remarked, "With a transformative tool like Webb, it’s hard to set expectations. Encountering features that mirror those of a forming planet area—even post-engulfment—was a complete surprise!"

Ryan Lau added, "This marks a pivotal moment in our exploration of such celestial events. This is the only instance we've witnessed in real-time, and the best detection of the aftermath. We hope to discover more events like this in future observations!"

Looking Ahead: More Discoveries Await!

These observations form part of a pioneering exploration program aimed at detecting rare, sudden infrared brightening events. NASA's telescopes are at the forefront of an expanding international effort to monitor cosmic phenomena, helping us unravel the mysteries of the universe.

With the Vera C. Rubin Observatory and NASA's Nancy Grace Roman Space Telescope set to launch, researchers are eager to uncover more exciting revelations about our ever-changing cosmos.