Astronomers have potentially captured the HD 135344B planet during its formation process, allowing for a new understanding of how planetary systems like ours come into existence
Using the European Southern Observatory’s (ESO) Very Large Telescope (VLT) in Chile, researchers have observed a young star, HD 135344B, surrounded by a disc of swirling gas and dust, with clear evidence of a planet carving out spiral arms within it.
This discovery marks the first time scientists have directly detected a planet candidate embedded inside a spiral pattern in a protoplanetary disc, the material surrounding a young star from which planets form.
A planet carving spirals
The star HD 135344B, located 440 light-years away in the constellation Lupus, is enveloped by a dense protoplanetary disc. These discs often feature rings, gaps, and spiral structures believed to be shaped by the gravitational influence of forming planets. While previous studies had observed spiral arms in this system, none had successfully identified the presence of a planet causing the pattern until now.
Using the VLT’s state-of-the-art ERIS (Enhanced Resolution Imager and Spectrograph) instrument, scientists detected a compact, bright signal at the base of one of the disc’s spiral arms. This signal is believed to be the light emitted by a planet still embedded in the disc, suggesting it is actively shaping the surrounding gas and dust as it grows.
This planet candidate is estimated to be about twice the mass of Jupiter and lies at a distance from its star similar to Neptune’s orbit around the Sun.
Planet hunting
The ERIS instrument, installed on the VLT in 2022, is proving to be a game-changer for direct imaging of young planetary systems. It allows astronomers to look deeper into dusty regions around young stars and detect faint objects that older technologies may have overlooked.
In the case of HD 135344B, ERIS enabled astronomers not only to see the spiral structures in greater detail but also to identify the likely cause: a forming planet. This represents a key step forward in confirming long-standing theories about how young planets influence their birth environments.
A young system under the microscope
In a separate but relevant study, another group of astronomers used ERIS to investigate a young star known as V960 Mon, also surrounded by a spiral-patterned disc. This system has exhibited signs of gravitational instability, where clumps of gas and dust collapse under their gravity, potentially leading to the formation of planets or brown dwarfs.
The team found a compact, luminous object near one of the spiral arms. Though its exact nature is still uncertain, it could be either a forming planet or a brown dwarf, an object too large to be a planet but not massive enough to ignite as a star.
If confirmed, this would be the first clear evidence of such an object forming through gravitational instability.
These observations open up new opportunities to witness planet formation as it happens, offering clues to understanding how planets, including those in our own solar system, form and evolve.
