Astronomers Unveil New Giant Planet in Binary Star System HD 135344 AB

A groundbreaking discovery in the field of astronomy has emerged with the identification of a young giant planet orbiting within the binary star system HD 135344 AB. This significant finding was made possible through advanced imaging technologies, particularly the Very Large Telescope (VLT) equipped with the SPHERE instrument. The study, published in the prestigious journal Astronomy and Astrophysics on July 13, 2025, provides new insights into the formation of planets in binary systems, a topic that has intrigued scientists for decades.

The binary star system HD 135344 AB consists of two young stars: an A-type main-sequence star and its companion, an F-type main-sequence star. The unique feature of this system is that while one star has already cleared its protoplanetary disk, the other continues to undergo active planet formation. Researchers, led by Tomas Stolker, an assistant professor at Leiden Observatory, initially focused on the secondary star due to the observable signs of ongoing planet formation, such as spiral arms and central cavities within its disk.

However, the primary star had largely been overlooked because it lacked visible disk material. The research team targeted this star for direct imaging, culminating in the discovery of HD 135344 Ab, a planet approximately ten times the mass of Jupiter, located at a distance of 15 to 20 astronomical units from its star. As Stolker noted, “Star A had never been investigated because it does not contain a disk. My colleagues and I were curious about whether it had already formed a planet. And so, after four years of careful measurements and some luck, the answer is yes.”

This discovery not only highlights the capabilities of modern astronomical instruments but also challenges previous assumptions regarding planetary evolution in binary systems. The astrometric measurements conducted during the study played a crucial role in confirming the planet’s existence despite its small angular separation from its star. The team utilized advanced techniques to differentiate the planet’s motion from that of background stars, a challenge that often complicates the detection of distant exoplanets.

The formation process of HD 135344 Ab provides valuable insights into the broader mechanisms that govern planet formation. Researchers speculate that this giant planet likely formed near the 'snowline' of its star's protoplanetary disk, a crucial region where volatile materials such as water and methane solidify. The presence of solid materials near the snowline is believed to facilitate the accretion of dust and gas into larger planetary bodies, an essential step in the formation of gas giants.

The implications of this discovery extend beyond the immediate findings about HD 135344 Ab. As astronomers continue to refine their imaging techniques, there is potential for uncovering additional close-in giant planets in similar star-forming regions. The anticipated release of data from the Gaia DR4 mission is expected to further enhance research capabilities, providing insights that could guide future direct imaging searches and improve algorithmic processing.

In summary, the discovery of the young giant planet HD 135344 Ab within the binary star system HD 135344 AB not only contributes to our understanding of planetary formation but also showcases the advancements in astronomical technology that enable such groundbreaking discoveries. As the field of astronomy progresses, it is likely that new findings will continue to reshape our understanding of planetary systems across the universe.