How can we observe the birth of a planet ? This is the challenge taken up by an international team led by LIRA, which has published a new study on AB Aurigae, a young star located some 530 light-years from Earth. Its vast disc of gas and dust, which is particularly bright and extensive, provides an exceptional laboratory for studying the early stages of planetary system formation.
Between 2019 and 2023, six observation campaigns carried out with SPHERE – the instrument on the Very Large Telescope (ESO) to which LIRA contributes – made it possible, for the first time, to track the rotation of a protoplanetary disc over a period of nearly four years. This veritable ‘time-lapse’ reveals a system far more complex than previously imagined.
The researchers show that the inner region of the disc does not behave as predicted by current models. They have also identified three compact structures, which may be protoplanets, as well as seven rapidly moving radial shadows on the surface of the disc. These clues point to a scenario in which several forming objects are interacting simultaneously with the gas and dust, although it is not yet possible to definitively confirm their nature.
