🌟 A star like our Sun lost its brightness for nine months: why?

A star like our Sun lost a large part of its brightness for nearly nine months. This unusual behavior immediately caught the attention of researchers, because stars similar to our Sun do not dim.

To study this event, astronomers mobilized several large telescopes, including Gemini South in Chile. The collected data showed that the drop in brightness came from a cloud of gas and dust passing in front of the star from our point of view, located about 3,000 light-years away. These results, published in The Astronomical Journal, offer valuable insight into the dynamic activity within planetary systems.


Located about 1.24 billion miles (2 billion kilometers) from the star, the cloud extends for about 124 million miles (200 million kilometers). It appears to be held together by the gravity of a secondary object orbiting the star. This object, which could be a planet or a brown dwarf, gives the cloud its coherent structure.

Analysis of the cloud's composition was conducted using the GHOST spectrograph installed on Gemini South. This instrument made it possible to analyze the star's light, revealing the presence of vaporized metals, such as iron and calcium. Even more remarkably, it enabled the measurement of the three-dimensional motions of the gas, highlighting dynamic winds inside the cloud.

These measurements show that the cloud moves independently of its host star, confirming that it belongs to a disk surrounding the secondary object. The star, named J0705+0612, is over two billion years old, indicating that the disk does not come from the initial planetary formation, but would rather result from a collision between planets.

This discovery demonstrates that even in mature systems, violent events like collisions continue to reshape the environment.

Planetary Collisions

Collisions between planets can occur even in old stellar systems, as this study suggests. Usually, debris disks are associated with young stars, formed during the initial phase of planet creation. However, the star observed here is over two billion years old.

In this case, researchers propose that the gas and dust cloud comes from a collision between two planets in the outer regions of the system. Such an impact ejects materials that can then clump together into a visible disk, temporarily obscuring the star.

These events are rare and allow us to grasp the long-term evolution of planetary systems. They reveal that gravitational instability can persist, leading to major reshaping. Collisions can scatter debris over vast distances, generating opaque structures.

Analyzing these phenomena helps anticipate how planetary systems, including our own, can evolve over time.