Formed just 50 million years after the dinosaurs went extinct, the newly discovered exoplanet is remarkably young by cosmic standards. Astronomers have identified a planet outside our solar system that orbits an unusually tight pair of parent stars—the closest such configuration ever directly imaged in a binary system. The twin suns in its sky likely resemble those of Tatooine, Luke Skywalker’s home world in Star Wars: A New Hope. Despite orbiting closer to its stars than any previously imaged circumbinary exoplanet, the planet’s year is extraordinarily long, taking roughly 300 Earth years to complete a single orbit.

The newly discovered planet, designated HD 143811 AB b, orbits the binary stars HD 143811 A and HD 143811 B in the HD 143811 AB system, located about 446 light-years from Earth. Its discovery is particularly significant because planets around binary stars are rarely detected, making this system a valuable laboratory for studying how planets form and evolve while orbiting two stars simultaneously.

Figure 1. llustration of the Tatooine-like exoplanet HD 143811 AB b

Of the roughly 6,000 exoplanets discovered so far, only a small fraction orbit binary star systems, and even fewer have been directly imaged. According to Jason Wang, an exoplanet imaging expert at Northwestern University, systems like this are especially valuable because they allow astronomers to observe both the planet and its twin host stars at the same time, making it possible to trace the motion of all three bodies across the sky. Continued observations will help scientists watch how the planet and binary stars move and interact over time, offering rare insight into the dynamics of such complex systems. Figure 1 shows llustration of the Tatooine-like exoplanet HD 143811 AB b.

A new world uncovered in ten-year-old observations

Although the exoplanet is new to astronomers, it was identified in archival observations nearly a decade old. Wang and his team found HD 143811 AB b in data collected by the Gemini South telescope using the Gemini Planet Imager (GPI), which detects exoplanets by blocking out the intense light of their host stars with a coronagraph—similar to creating an artificial eclipse—and sharpening faint planetary signals with adaptive optics.

GPI operated at Gemini South from 2014 to 2022 before being removed and transferred to the University of Notre Dame for a major system upgrade known as GPI 2.0. Once the upgrades are completed next year, the instrument will be installed on the Gemini North telescope atop Mauna Kea, Hawaii, where it will resume exoplanet imaging with enhanced capabilities.

The discovery emerged when Jason Wang and his colleagues revisited archival data from the Gemini Planet Imager ahead of its upgrade to GPI 2.0. While the team did not expect to uncover new planets, a careful reanalysis proved worthwhile. During GPI’s operational lifetime, observations of more than 500 stars yielded only a single new planet—highlighting just how rare such detections are.

Team member Nathalie Jones of CIERA examined GPI data collected between 2016 and 2019 and cross-checked it with observations from the W.M. Keck Observatory [1]. This process revealed a faint object moving in tandem with a star, a key indicator that it was gravitationally bound rather than a background object. By comparing stellar light with reflected planetary light, the team confirmed that the object—first imaged in 2016 but previously overlooked—was indeed the exoplanet HD 143811 AB b, a conclusion independently supported by researchers at the University of Exeter.

Further analysis showed the planet is massive, roughly six times the size of Jupiter, and extremely young at about 13 million years old [1]. While that may seem ancient, it is only around 50 million years after the extinction of the dinosaurs and is considered youthful on cosmic timescales, meaning the planet still retains heat from its formation.

The planet orbits a tightly bound binary star system whose two stars circle each other every 18 Earth days. Despite being closer to its stellar hosts than most known circumbinary planets, HD 143811 AB b takes an extraordinary 300 Earth years to complete a single orbit. How such a planet formed in this environment remains unclear, largely because so few similar systems have been observed.

To resolve these mysteries, the team plans to secure additional telescope time to track both the planet’s orbit and the motion of its parent stars, while continuing to search archival data for more hidden worlds. The findings were published on December 11 in The Astrophysical Journal Letters.

Reference:

1. https://www.space.com/astronomy/exoplanets/astronomers-discover-images-of-a-tatooine-like-exoplanet-with-a-bizarre-orbit-hidden-in-10-year-old-data

Cite this article:

Janani R (2025), Astronomers Capture Images of a Rare Tatooine-Like World on A 300-Year Orbit, AnaTechMaz, pp.709