A large cloud blocking the light from a distant star has been discovered to be made of swirling metal vapor. Even more intriguing, this cloud is linked to another mysterious object that might be a massive planet or a small star.
Astronomers first noticed this metallic cloud in September 2024. A sun-like star called J0705+0612, located about 3,000 light-years away, suddenly dimmed by 40 times its usual brightness and stayed that way for nine months. It returned to normal brightness in May 2025. This rare event caught the attention of astronomer Nadia Zakamska from Johns Hopkins University. “Stars like the sun don’t just stop shining for no reason,” she explained.
Zakamska and her team used the Gemini South telescope in Chile and other telescopes to gather data on J0705+0612. They found that the star had been temporarily obscured by a vast cloud of gas and dust, which is about 120 million miles wide—15,000 times wider than Earth. This cloud was roughly 1.2 billion miles away from the star when it caused the dimming, equivalent to about 13 times the distance from Earth to the sun.
The researchers discovered that the cloud is gravitationally bound to another object orbiting J0705+0612, which must have at least several times the mass of Jupiter. This raises an important question: what exactly is this unknown object? If it’s a star, the cloud is part of a circumsecondary disk. If it’s a planet, it’s a circumplanetary disk. Observing such a cloud blocking a star is extremely rare.
To learn more about the cloud’s make-up, the researchers turned to Gemini South’s High-resolution Optical Spectrograph (GHOST). They observed the cloud for two hours, aiming to reveal its chemical composition. Zakamska remarked, “The result exceeded all my expectations.”
They found the cloud rich in “metals”—elements heavier than hydrogen and helium, like iron and calcium. This allowed the team to create a 3D map of the cloud’s gas movements for the first time. The sensitivity of GHOST enabled them to track how the gas was moving, confirming it was separate from its host star and connected to the celestial body orbiting it.
The researchers suggest the cloud could have formed when two planets around J0705+0612 collided, scattering dust and debris. Such collisions are common in younger planetary systems but unusual for this older system, estimated to be around 2 billion years old. “Even in mature planetary systems, dramatic collisions can still occur,” said Zakamska. “The universe is a continuous cycle of creation, destruction, and transformation.”
This research sheds light on how dynamic and unpredictable space can be, reminding us that even seemingly stable systems can experience significant change. Such findings help broaden our understanding of planetary dynamics and their evolution over time.
The study was published in The Astronomical Journal on January 21.
