A planet less than a million years old was found in old images: it is still being born

Astronomers have found the youngest known exoplanet — Elias 2-24 b, which researchers estimate to be less than one million years old. The planet, with a mass roughly that of Jupiter, was discovered in archival observations of a star located 450 light-years from Earth.

Space.com reports this.

Elias 2-24 b orbits a young star surrounded by a disk of gas and dust. The planet is still embedded in the material from which it formed, allowing astronomers to study it at an exceptionally early stage of development.

Previously, the youngest known exoplanets were several worlds aged over five million years. The new object is estimated to be at least five times younger than the previous record-holders.

Lucas Seisa, a co-author of the study from the Institute of Astrophysical Research in Chile, noted that the existence of such a young planet is difficult to explain with current models of planet formation. He said the discovery shows that these models do not yet account for some important processes that occur during planet birth.

Finding Elias 2-24 b was helped by archival data from the Keck Observatory in Hawaii. An international group of researchers led by Chilean University graduate student Diego Portales Andrea Bernardi reanalyzed observations of the star Elias 2-24.

Earlier, the ALMA radio telescope and the Very Large Telescope of the European Southern Observatory recorded signs that there might be an unknown object in the star’s dusty disk. Scientists noted a gap in the disk where material was less abundant than in surrounding regions.

Such gaps can arise under the influence of planets forming and interacting with the gas and dust around them. It was in one of these gaps that researchers discovered Elias 2-24 b.

According to Bernardi, astronomers deliberately searched for a planet inside the dust disk gap because its presence could explain the appearance of this gap.

Detecting a planet at such an early stage is challenging: young worlds are hidden within the gas and dust surrounding their stars. Most exoplanets already known are much older, so directly studying their formation is not possible.

Elias 2-24 b provides scientists with an opportunity to observe the initial stages of planet formation and to test how well theoretical models describe the processes occurring in young planetary systems.