Astronomers Discover Exoplanet Orbiting Twin Stars Like Tatooine

Astronomers have made a groundbreaking discovery of an exoplanet that orbits two suns, similar to the fictional planet Tatooine from the “Star Wars” franchise. The planet, designated HD 143811 AB b, is located approximately 446 light-years from Earth in a binary star system. This finding was published in a study in the journal Astronomy & Astrophysics by researchers from Northwestern University in Chicago, Illinois.

The newly identified exoplanet is a gas giant that orbits its twin stars at a distance closer than any other previously observed in a binary system. The unique characteristics of HD 143811 AB b allow astronomers to study the movements of both the planet and its stars, providing invaluable insights into their interactions. As noted by Jason Wang, an exoplanet imaging expert at Northwestern University, “Of the 6,000 exoplanets that we know of, only a very small fraction of them orbit binaries. Of those, we only have a direct image of a handful of them.”

The planet’s proximity to its twin stars is remarkable. While it is six times closer to its light sources than any other exoplanet previously imaged, it remains approximately 80 times further from its suns than Earth is from the Sun. This means that HD 143811 AB b takes about 300 years to complete a single orbit, while its binary stars revolve around each other every 18 days. Notably, the exoplanet is estimated to be six times the size of Jupiter.

The discovery of HD 143811 AB b is not entirely new; it was identified using archival data collected a decade ago by the Gemini South telescope and its Gemini Planet Imager (GPI). Wang and his team revisited this data, originally gathered between 2016 and 2019, and cross-referenced it with information from the W.M. Keck Observatory. They detected a faint object that appeared to be moving in tandem with a star, leading them to conclude that it was indeed a planet.

Wang emphasized the significance of this movement: “If a planet is bound to a star, then it will move with the star. Sometimes, when we revisit a ‘planet,’ we find it’s not moving with its star. Then, we know it was just a photobombing star passing through.” The team confirmed the presence of the planet, a conclusion later verified independently by astronomers from the University of Exeter in the UK.

One striking characteristic of HD 143811 AB b is its extreme temperature, recorded at 1,416°F (around 780°C), nearly double that of Venus. The planet is relatively young, at approximately 13 million years old, compared to Earth’s formation around 4.6 billion years ago. The formation mechanisms of such planets in binary systems remain unclear, with Wang stating, “Exactly how it works is still uncertain. Because we have only detected a few dozen planets like this, we don’t have enough data yet to put the picture together.”

The research team plans to continue monitoring the orbits of both the planet and its stars to deepen their understanding of the dynamics within binary star systems. This ongoing investigation could shed light on the complex interactions between stars and their orbiting planets, opening new avenues for astronomical research.