THE BEST BABY PICTURE OF A NEWBORN PLANETDate: 2018-07-07
About 370 light years away from Earth, a new, big and 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 images show 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 is dubbed as the PDS 70 and 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 larger 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. "Now we have the evidence that there’s at least one."
The astronomers used an instrument to block out the light from the star in order to get the picture of the planet, this process is known as a coronagraph. Detecting the planets around distant stars can be incredibly difficult, as the starlight usually overpowers the much dimmer planet. A coronagraph makes it possible to see and snap a picture of the nearby planet, named the PDS 70b. This technique also made astronomers learn that the planet is 22 times farther out from its star than Earth is to the Sun, a similar gap between the Sun and Uranus.
This planet is, however, hotter than Uranus or any other planet in our Solar System, it has a cloudy surface that is about 1,000 degrees Celsius, according to the team's analysis.
It is not always certain if astronomers have, indeed, found a planet or if they have picked up some other feature within a star's disk. "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.
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 characterise the system and learn much more in greater detail about young planets."