Have you ever wiped a shelf with a cloth and watched the dust particles float away in a beam of light? That dust – ordinary, everyday dust – is a cousin of the dust that, 4.5 billion years ago, formed the Earth. Grain by grain, these tiny particles clumped together, stuck together and compacted, eventually forming rocks, then entire planets.

Our Sun, for its part, was fortunate enough to be alone. No neighbours to disrupt this delicate ballet, no foreign gravity to scatter the dust before it could become a world. But in our Galaxy, this solitude is an exception: the majority of stars live in pairs, trios, or even quartets. In these turbulent systems, does dust stand a chance of surviving long enough to form planets?

This is precisely the question Nicolás Cuello has been tackling since his arrival at the University of Grenoble Alpes in December 2023. As head of the Stellar-MADE team, he combines hydrodynamic simulations, celestial mechanics and observations from the ALMA radio telescope to unravel the secrets of planetary formation in the most turbulent environments in the Universe.

Studying how planets form around multiple stars also means looking at our own Solar System from a radically new perspective.

When stars disturb one another

Protoplanetary discs are those immense, thick rings of gas and dust – several times the size of the Solar System – that surround young stars and within which planets gradually form. In a single-star system, this disc evolves in a relatively orderly manner. But what happens when one, or more, companion stars disrupt this fragile balance?

The gravitational forces generated by the stellar companions can twist, tear or fragment the discs. They alter the dynamics of the dust grains, accelerating or halting their growth into planetesimals. They can even trigger violent accretion episodes comparable to the outbursts of brightness seen in so-called FU Orionis stars – sudden, temporary flashes revealing a sudden influx of matter onto the star, radically altering the chemical composition of the disc’s earliest solids.

A concrete example: the triple system V892 Tau harbours a circumbinary disc, orbiting the two central stars in the manner of the Tatooine-type planets so beloved of *Star Wars*, whose disturbed morphology has been analysed in detail by the team (Alaguero et al., 2024 and 2025). This research illustrates how multi-body interactions shape the environment in which the first circumbinary planets might form.

Alpha Centauri, TOI-2267 and the planets of the future

Far from being purely theoretical, Nicolás Cuello’s research is rooted in very real systems. The closest triple star system to the Sun, comprising the binary star Alpha Centauri and Proxima Centauri, was the subject of a dynamical modelling study published in 2024. The team asked themselves: how much material was once available in the discs around the two stars of Alpha Centauri to form planets? This is a practical question, given that planets have been confirmed around Proxima Centauri, and others are proposed in Alpha Centauri, making this neighbouring triple star system a fascinating natural laboratory. More recently, the discovery of Earth-like exoplanets in the TOI-2267 binary system opens up a further possibility: Earth-like planets can indeed form in multi-star environments.

The simulations developed by the Stellar-MADE team can now guide future astronomical observations by identifying which systems are most likely to host planets – a major challenge for missions such as PLATO (ESA), the VLT telescopes, and the ALMA and SKA radio telescopes.

A project deeply rooted in society

Beyond his publications and international conferences, Nicolás Cuello has made the dissemination of knowledge an integral part of his project. A scientific comic book on exoplanets, translated into four languages, enables him to share the mysteries of planetary diversity with the public. Visits to local schools and exhibitions on solarography to observe the Sun’s path across the sky are just some of the initiatives that anchor fundamental research in everyday life.

After all, understanding how planets form around other stars also means gaining a better understanding of why our own Solar System took the form it did, and what it might become in the distant future.

These stellar interactions shape the final structure of planetary systems long before the first planet comes into existence.

Outlook: a rapidly growing discipline

Planetary formation in multiple star systems remains one of the most open areas of research in contemporary astrophysics. Whilst observations from the ALMA telescope have revolutionised our understanding of protoplanetary discs, many questions remain: how exactly do giant planets form in these perturbed environments? What planetary architectures are possible around triple or quadruple star systems? How can we better detect these exoplanets using next-generation instruments?

The Stellar-MADE team, which is fully operational and part of major international collaborations (FAUST, exoALMA, PLACID, PLATO), is currently one of the few to tackle these questions in such an integrated manner, combining modelling, observation and celestial mechanics. An approach which, as instruments gain in resolution, promises major discoveries in the years to come.