An image of the newborn planet and its host star. The dark circle at the centre is a mask that blocks the light of the central star so astronomers can see the fainter disc and planet. The planet is the bright spot to the right of the black circle. Image Credit: ESO/A. Müller et al.
Astronomers have captured an image of an exoplanet forming in the dusty disc around a young star.
The star in question is a young dwarf called PDS 70. ESO’s Very Large Telescope was used to image of the young exoplanet, named PDS 70b, forming around it.
The SPHERE instrument on the VLT was able to measure the brightness of the planet at different wavelengths, allowing the planet’s atmosphere to be analysed.
After stars form, the remnants of their stellar ingredients remain as a dusty protoplanetary disc around the star.
Over time, grains of dust coalesce to form larger bodies, which continue accreting material until they become planets in orbit.
PDS 70b is about three billion km from its host star, about the same as the distance between Uranus and the Sun.
It is thought to be a gas giant planet with a mass a few times that of Jupiter, and its surface temperature is about 1,000°C.
“These discs around young stars are the birthplaces of planets, but so far only a handful of observations have detected hints of baby planets in them,” explains Miriam Keppler, who lead the team behind the discovery.
“The problem is that until now, most of these planet candidates could just have been features in the disc.”
A video zooming in on young dwarf star PDS 70 in the constellation of Centaurus.Credit: ESO, N. Risinger (skysurvey.org), DSS
The exoplanet has also managed to reshape the protoplanetary disc while it has been orbiting the star, creating a gap in the dust.
These gaps have been seen before in other observations of young stars, but this is the first time the planet has been seen at the same time.
“Keppler’s results give us a new window onto the complex and poorly-understood early stages of planetary evolution,” comments André Müller, leader of a second team that conducted follow-up investigations.
“We needed to observe a planet in a young star’s disc to really understand the processes behind planet formation.”