Astronomers have made an exciting find: a planet orbiting twin stars, called HD 143811 AB b, located 446 light-years from Earth. This planet is particularly intriguing because it orbits its stars much closer than any previously discovered exoplanets in binary systems. Think of the twin suns seen in Tatooine from Star Wars—that’s what makes this discovery so interesting! However, HD 143811 AB b has a long orbital period, taking about 300 Earth years to complete one revolution around its stars.
These findings present a rare opportunity for scientists. Planets around binary stars are uncommon, which means HD 143811 AB b can help researchers understand how planets and stars interact. Jason Wang, an expert from Northwestern University, explains that out of the 6,000 known exoplanets, very few orbit binary systems. This makes imaging both the planet and its stars a unique chance to study their movements together.
The discovery of HD 143811 AB b was made by revisiting data collected almost a decade ago. The Gemini South telescope, equipped with a device called the Gemini Planet Imager (GPI), played a key role. GPI worked by blocking out the bright light from the stars to capture the faint glow of nearby planets, much like a solar eclipse. This telescope will soon undergo an upgrade to enhance its capabilities further.
The recent discovery came as a surprise to the team. Wang admitted they didn’t expect to find a new planet while revisiting the old data. The chance of finding more planets in archived information is an avenue they plan to explore further. In fact, even during GPI’s operational years, they observed over 500 stars yet found only one new planet. This clearly shows how rare these exoplanets can be.
Nathalie Jones, another team member, analyzed GPI data alongside information from the W.M. Keck Observatory. This thorough review led to the identification of HD 143811 AB b—a sizable planet, about six times larger than Jupiter, and roughly 13 million years old. While this might sound old by our standards, in the context of the universe, it’s relatively young—just 50 million years after the dinosaurs became extinct. Its young age suggests that HD 143811 AB b still retains some of the heat from its formation.
Interestingly, the twin stars in this binary system also orbit each other quickly, completing a cycle every 18 Earth days. But HD 143811 AB b remains distant in terms of its own orbit, emphasizing how unique this planetary system is.
Despite these findings, there are still many unanswered questions about how HD 143811 AB b formed. Wang points out that the rarity of such planets means our knowledge is still growing. The team plans to seek additional telescope time to monitor the movements of HD 143811 AB b and its stars, aiming to better understand their interactions.
As researchers continue to delve into archival data for new planets, Jones emphasizes that there are still many mysteries to uncover. Their research was recently published in The Astrophysical Journal Letters, sparking further interest in exploring the cosmos.
