This may be the first image of a baby planet coming into existence

20 May 2020

Scientists believe that the ‘twist’, seen in very bright yellow, marks the spot where a planet is forming. Image: ESO/Boccaletti et al

Astronomers have discovered the tell-tale signs of a star system being born, including a ‘twist’ that could be our first ever glimpse of a baby planet forming.

Observations made using the European Southern Observatory’s (ESO) Very Large Telescope (VLT) have helped reveal a stunning image of a spiral of dust and gas during the birth of a new star system.

This system, dubbed AB Aurigae, is located 520 light years away from Earth in the constellation Auriga, often referred to as ‘the charioteer’. While astronomers have known for some time that planets are born in such dusty discs surrounding young stars, this latest discovery came with a ‘twist’.

Based on the information they’ve collected, the astronomers believe this twist marks the site of the first direct evidence of a baby planet coming into existence. According to Emmanuel Di Folco of the Astrophysics Laboratory of Bordeaux, spirals of this type ‘kick’ the gas to create wave-like disturbances in the disc, much like the wake of a boat on a lake.

As the baby planet rotates around the central star, this wave gets shaped into a spiral arm. In the image released by ESO, the very bright yellow twist region close to the centre of AB Aurigae lies at about the same distance from the star as Neptune is to the sun.

The region is just one of the disturbance sites where the astronomers believe a planet is being made. The first hints of this region’s importance came after observations made a few years ago by the Atacama Large Millimeter/submillimeter Array (ALMA).

Wide-field view of the region of the sky where AB Aurigae is located.

Wide-field view of the region of the sky where AB Aurigae is located. Image: ESO/Digitised Sky Survey 2. Acknowledgement: Davide De Martin

An expected twist

At that time, ALMA revealed two spiral arms of gas close to the star, lying within the disc’s inner region. Then, in 2019 and early 2020, Anthony Boccaletti and a team of astronomers from France, Taiwan, the US and Belgium set out to capture a clearer picture by turning the Sphere instrument on ESO’s VLT in Chile toward the star. This helped reveal the closest images of the system to date.

Speaking of the twist seen in the images, Anne Dutrey, co-author of the study revealing the astronomers’ findings, said: “The twist is expected from some theoretical models of planet formation.

“It corresponds to the connection of two spirals – one winding inwards of the planet’s orbit, the other expanding outwards – which join at the planet location. They allow gas and dust from the disc to accrete onto the forming planet and make it grow.”

Once ESO’s Extremely Large Telescope is up and running in a few years’ time, the researchers said they will be able to see even more detailed views of planets in the making.

Boccaletti, who led the study, said: “We should be able to see directly and more precisely how the dynamics of the gas contributes to the formation of planets.”

Colm Gorey was a senior journalist with Silicon Republic