Astronomers See Mysterious Metallic Cloud Surrounding Something Very Mysterious
A team of researchers investigating the star’s dramatic dimming has revealed a cloud of dust and gas nearly 120 million miles (200 million kilometers) across. What exactly caused the cloud to form, and the nature of the material involved, is unknown.
From September 2024 to May 2025, the Sun-like star designated J0705+0612 experienced a 40-fold dimming. Researchers describe the phenomenon in a study published today in the Astronomical Journal, which identifies the victim as a large, slowly rotating cloud.
“Stars like the Sun don’t just stop shining for no reason,” Nadia Zakamska, professor of astrophysics at Johns Hopkins University and co-author of the study, in a NOIRLab statement, “fading events like this are extremely rare.”
A bad cloud
In this case, Zakamska and his colleagues combined the telescopic observations with the star’s data and concluded that a cloud of dust and gas, for a short time, obscured the star. According to their estimates, the distance between this feature and the star is about 1.2 billion miles (2 billion kilometers). The star is located 3,000 light years from Earth.
Cue a mysterious third player: a gravitational pull appears to connect the cloud to another body at the edge of the J0705+0612 planetary system. Researchers do not yet know what this body is. It orbits J0705+0612 and needs to have enough mass to keep the cloud from breaking apart. According to their findings, there should be several Jupiter masses—at least. A very massive exoplanet, a brown dwarf, or a very low-mass star are possible candidates.
If the body is a star, the cloud would be a circumsecondary disk—debris orbiting a dwarf companion in a binary system. If it is a planet, the cloud would be a rotating disk. In general, it is rare for researchers to see a star directly eclipsed by the disk of a secondary object.
What’s in the cloud?
Zakamska says: “When I first looked at the occultation with spectroscopy, I hoped to reveal something about the chemical composition of the cloud, as such measurements had never been made before.
The team found a number of instruments in the cloud. To astronomers, metals are heavier elements than helium. They also directly recorded the movement of the gas in three dimensions, revealing a “volatile environment with winds of gaseous metals,” such as calcium and iron, according to the statement.
J0705+0612 and the cloud move independently, as revealed by team measurements of wind direction and speed. Combined with the obscuration length, this provides further confirmation of the group’s theory that the obscuring object is another disk of matter orbiting the periphery of the J0705+0612 stellar system.
“The sensitivity of GHOST allowed us to not only see the gas in the cloud, but to measure how it moves,” Zakamska said. GHOST (Gemini High-resolution Optical Spectrograph) is the instrument they used to study cloud formation. “That’s something we’ve never been able to do before in a program like this.”
How was it formed?
The team found an infrared excess—an overabundance of infrared light—that typically indicates the presence of a protoplanetary disk, the debris surrounding a star where planets begin to form. However, J0705+0612 is by no means young. It is more than two billion years old, which means it should not have such a disk. As such, the cloud in question is probably not a remnant from when the star was young and the system was producing planets.
As for how the disk formed, the two planets likely created a cloud by colliding at the edge of the J0705+0612 planetary system, spewing debris, dust, and rocks, the researchers argue.
“This event shows us that even in mature planetary systems, spectacular, massive collisions can still happen,” Zakamska said. “It’s a stark reminder that the Universe is still—it’s an ongoing story of creation, destruction, and transformation.”
