Scientists have used the Very Large Telescope (VLT) in Chile to take a look at planet-forming disks around other stars. And the resulting images are just wonderful.
The images were taken using the SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) instrument on the VLT. The eight stars that were imaged range in distance from 230 to 500 light-years from Earth.
And they reveal dusty disks around the stars where we think planets are forming. These are all young planetary systems, thought to resemble our own Solar System more than 4 billion years ago. A study describing the findings will be published in the Astrophysical Journal, with a pre-print available on arXiv.
“This high-quality dataset impressively shows the power of SPHERE for these observations and significantly increases the number of planetary nurseries studied at high resolution enabling us to eventually get a statistical grasp on planet formation,” Sascha Quanz from ETH Zurich in Switzerland, one of the study’s co-authors, said in a statement.
The disks all vary wildly in size and shape, ranging from 160 AU across (astronomical units, 1 AU is the Earth-Sun distance) to more than 1,400. All of them were T Tauri stars, which are a class of stars less than 10 million years old that vary in brightness. The disks contain gas, dust, and building blocks of planets known as planetesimals.
In fact, the images taken in March 2016 are so detailed that we can actually see the effects of some of these planets forming. You can clearly see circular bands in the disks where young planets are already carving out a path, sweeping up any material they encounter.
And from the images you can see how different these disks look. Some are hazier than others, while a few have clearly defined orbital paths from existing planets. We’re also seeing them in different orientations, some face-on to us and others almost edge-on.
The main purpose of SPHERE is to try and directly image exoplanets orbiting nearby stars. However, it’s now also been used to look at these younger stars, called the DARTTS-S (Discs ARound T Tauri Stars with SPHERE) survey, and to see planet formation in action.
For now, it’s hoped that these findings will tell us more about T Tauri disks. There’s a lot we don’t understand about planet formation, so seeing more young stars like these could help us answer how other planets, and those in our own Solar System, came to be.
