Astronomers snap one of the best baby pics yet of a newborn planetJuly 2, 2018
Around 370 light years away from Earth, a big, cloudy planet is in the middle of being born — and astronomers have snapped an incredibly detailed image of its birthing process. The picture is one of the most robust we have of a planet forming, and it could help us learn more about how worlds outside our Solar System came to be.
Scientists at the Max Planck Institute, working with the European Southern Observatory’s Very Large Telescope in Chile, were able to capture a planet about a few times the mass of Jupiter in the midst of forming around a young star. The image shows the object taking shape inside the large cloud of gas and dust that surrounds new stars, what is known as a protoplanetary disk. These disks are made up of all the materials leftover when a star is born, and the dust within them can converge to form new planets.
This star, dubbed PDS 70, is thought to be just 5.4 million years old — a newborn on the cosmological timescale. Astronomers have thought for a while that new planets might be emerging around the star. Previous images of the sun showed large areas within its protoplanetary disc where the material has been cleared away. That’s usually a good indicator that planets are forming inside; the new worlds are gobbling up the gas and dust within the disk to grow larger. “For some time it was suspected that planets might be forming in this disk,” Miriam Keppler, a doctoral student at the Max Planck Institute and lead author of a paper detailing the planet’s discovery, tells The Verge. “Now we have the evidence that there’s at least one.”
To get the picture of the planet, the astronomers used an instrument to block out the light from the star, known as a coronagraph. Detecting planets around distant stars can be incredibly difficult, as the starlight usually overpowers the much dimmer planet. But a coronagraph made it possible to see and snap a picture of the nearby planet, named PDS 70 b. This technique helped astronomers learn that the planet is 22 times farther out from its star than Earth is to the Sun — a distance similar to the gap between our Sun and Uranus. However, this planet is much hotter than Uranus or any other planet in our Solar System. It has a cloudy surface that’s about 1,832 degrees Fahrenheit (or 1,000 degrees Celsius), according to the team’s analysis.
Astronomers have captured images of planets being born around distant stars before, but Keppler says the authenticity of those pictures are often debated. It’s not always certain if astronomers have, indeed, found a planet or if they’ve picked up some other feature within a star’s disk. Images of protoplanetary disks have to go through a lot of processing, and the algorithms that astronomers use can sometimes make it seem like a planet exists around a star when one isn’t there. However, Keppler is confident that this is the best detection yet of a planet being born around a star, as they’ve been studying this system for a while in a number of different ways.
“We’ve taken images at various different dates, used different algorithms, different wavelengths of light,” says Keppler. “If it was [an anomaly] we would not have detected it in such a consistent way.”
Keppler and the astronomy team plan to keep observing this forming star system, too. André Müller, a Max Planck researcher who led the imaging team, says they hope to gain some insight on how long it takes for new planets to come together and what processes are needed to form a baby world. “With our data and future observations, we’ll be able to better characterize the system and learn much more in greater detail about young planets.”