UNM Astronomers Unveil Dynamic Multi-Planet System

Researchers confirm three bodies orbiting the exoplanet system TOI-201, including a super-earth, warm Jupiter, and brown dwarf

Apr. 16, 2026 at 4:06am

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A bold, geometric abstract painting in soft colors depicting the complex, intertwining orbits and gravitational interactions of the three planets in the TOI-201 exoplanet system, conveying the structural order and dynamism of this distant planetary system.An abstract visualization of the dynamic, tilted orbits of the three bodies in the TOI-201 exoplanet system, offering a rare real-time glimpse into the evolution of distant planetary architectures.Albuquerque Today

Astronomers at the University of New Mexico have published new research confirming three bodies orbiting the dynamic exoplanet system TOI-201. The system includes a super-earth (TOI-201 d), a warm Jupiter (TOI-201 b), and a brown dwarf (TOI-201 c) - the most massive body besides the star. The researchers used a combination of observational techniques like spectroscopy, transit photometry, transit timing variations, and astrometry to study the system's unique three-dimensional architecture and dynamic interactions.

Why it matters

This multi-planet system is scientifically interesting because it exhibits rare real-time changes in the planets' orbits, providing a window into how planetary systems like our own Solar System form and evolve over time. The tilted orbits of the planets in TOI-201 also challenge the typical assumption that planets are born aligned in the same plane as the protoplanetary disk.

The details

The super-earth TOI-201 d is a rocky planet about 1.4 times the size of Earth and 6 times its mass, orbiting every 5.85 days. The warm Jupiter TOI-201 b is a gas giant about half the mass of Jupiter, orbiting every 53 days. The brown dwarf TOI-201 c is the most massive body in the system besides the star, on a wide, highly elliptical 8-year orbit. Its gravitational influence is responsible for the system's dynamic behavior. TOI-201 c is also the longest-period transiting object ever discovered.

  • The next transit of TOI-201 c is predicted for March 26, 2031.
  • In 200 years, the super-earth will stop transiting, followed by the warm Jupiter a few hundred years later, and the brown dwarf thousands of years in the future.

The players

Ismael Mireles

A PhD candidate in the UNM Department of Physics and Astronomy, who led the research on the TOI-201 system.

Diana Dragomir

A professor at the University of New Mexico who advised Mireles on the research.

Alain Triaud

A professor at the University of Birmingham who contributed to the study by providing observations from the ASTEP telescope in Antarctica.

TOI-201

The dynamic exoplanet system studied by the UNM researchers, which includes a super-earth, warm Jupiter, and brown dwarf.

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What they’re saying

“The goal was to characterize the TOI-201 planetary system to understand not just what planets are there, but how they interact with each other dynamically. This helps scientists understand how planetary systems like our own Solar System form and evolve over time.”

— Ismael Mireles, PhD candidate, UNM Department of Physics and Astronomy

“Since the mass of TOI-201 c is near the boundary separating massive planets from brown dwarfs, one mystery this system poses is whether this body formed like a planet or like a star.”

— Diana Dragomir, Professor, University of New Mexico

“Our contribution was enabled by having a telescope in Antarctica. Whilst the logistics involved are difficult, the telescope's unique location and access to optimal astronomical conditions are key to studying exoplanetary systems with long orbital periods such as TOI-201.”

— Alain Triaud, Professor, University of Birmingham

What’s next

The next transit of TOI-201 c is predicted for March 26, 2031, which will provide a rare opportunity for follow-up observations worldwide, including by citizen scientists.

The takeaway

The TOI-201 system is a rare example of a multi-planet exoplanet system where the planets' orbits are actively changing on human timescales, offering astronomers a unique real-time window into how planetary systems form and evolve. The tilted orbits of the planets also challenge existing models of planet formation, raising new questions about the origins of this dynamic system.