For the First Time Ever, Astronomers Have Observed a the Birth of a Planet
At only two million years old, the LkCa 15 is a cosmic nursery.
Concept art of the LkCa 15 system. Image: NASA/JPL-Caltech
Nearly 2,000 exoplanets—or, worlds beyond our Solar System—have been discovered over the last two decades, demonstrating that there is spectacular planetary diversity in the universe. But while astronomers have observed everything from Earthlike planets to mega-Saturns, one particular category has proved consistently difficult to capture: baby exoplanets, in the act of formation.
Now, for the first time ever, astronomers have produced direct snapshots of one of these germinal worlds, which are featured in this video, along with concept art illustrating the system.
The new research, published this week in Nature, provides hard evidence of a developing gas giant orbiting a young Sunlike star called LkCa 15, located 450 light years away in the constellation Taurus. What's more, it appears as if at least two other giant bébés are also forming around the star, though only one was directly detected.
"No one has successfully and unambiguously detected a forming planet before," said astronomer Kate Follette, a co-author on the study, in a statement. "There have always been alternate explanations, but in this case we've taken a direct picture, and it's hard to dispute that."
Follette and her colleagues made the discovery by screening the LkCa 15 system for high-energy hydrogen-alpha emissions, which are generated by the chaotic interactions between the planet and its star's circumstellar disk of dust and gas. This unique spectral signature is a smoking gun for planetary birth, and astronomers hope to use it to root out other planets in the process of creation.
"Results like this have only been made possible with the application of a lot of very advanced new technology to the business of imaging the stars," co-author Peter Tuthill told UANews.com. "It's really great to see them yielding such impressive results."