Astronomers Uncover Massive Metallic Cloud Obscuring Distant Star

A substantial cloud, consisting of swirling winds of vaporized metal, was observed blocking light from a distant star, J0705+0612. This cloud appears gravitationally bound to a separate, unidentified object, which could be either a massive planet or a low-mass star.

Astronomers initially detected this metallic cloud in September 2024 when J0705+0612, a sun-like star located approximately 3,000 light-years away, experienced a significant dimming event. The star's light was blocked for nine months before regaining its original brightness in May 2025.

Johns Hopkins astronomer Nadia Zakamska noted the rarity of such dramatic dimming events for stars resembling the sun.

A Rare Celestial Veil

Zakamska and her team conducted follow-up observations using the Gemini South telescope, the Apache Point Observatory 3.5-meter telescope, and the 6.5-meter Magellan Telescopes. By combining these new observations with archival data, they confirmed that the star had been temporarily occulted by a vast, slow-moving cloud of gas and dust.

The cloud's estimated width is around 120 million miles (200 million kilometers), which is approximately 15,000 times the diameter of Earth. It was situated about 1.2 billion miles (2 billion km) from J0705+0612 when the dimming occurred, a distance roughly 13 times that between Earth and the sun.

Unveiling the Cloud's Guardian

Researchers determined that this cloud is gravitationally bound to another object that also orbits J0705+0612. This companion object must possess sufficient mass to maintain the cloud's structure, implying it is at least several times the mass of Jupiter.

The precise nature of this mystery object remains an open question: it could be a less massive star within a binary system (making the cloud a circumsecondary disk) or a planet (making it a circumplanetary disk).

Advanced Observations Confirm Metallic Nature

To ascertain the cloud's composition, the team utilized Gemini South's Gemini High-resolution Optical SpecTrograph (GHOST).

Zakamska stated that the results regarding the cloud's chemical composition surpassed her initial expectations.

The team identified the cloud as rich in elements heavier than hydrogen and helium, commonly termed "metals" by astronomers. These include iron and calcium. These gaseous metal winds were mapped in three dimensions, marking the first instance where the internal gas motions of a disk orbiting a secondary object (such as a planet or low-mass star) have been measured in such a system. Zakamska highlighted GHOST's sensitivity, which allowed for both the detection and measurement of the gas movement within the cloud.

Mapping the speed and direction of winds inside the cloud confirmed that it moves independently of its host star, reinforcing its gravitational association with a secondary object situated in the outer regions of this planetary system.

Collision in a Mature System?

The team posits that this cloud may have originated from a collision between two planets orbiting J0705+0612, an event that would have dispersed dust, rocks, and other debris. While such collisions are common in young planetary systems, this particular system is estimated to be around 2 billion years old, making the event unusual for its age.

Zakamska remarked that this event suggests large-scale collisions can still occur even in mature planetary systems.