Variability in the DQ Tau binary system shapes its surrounding planet-forming disk

Star system: DQ Tauri A | Distance from the Sun: 637 light years

The planet-forming disk surrounding the young binary star system DQ Tau is significantly influenced by the variable radiation and matter-gathering processes of its host stars. By analyzing light emissions from the disk, it is possible to understand how stellar activity, such as X-ray flares and changes in accretion—the process where a star pulls in material from its surroundings—impacts the physical and chemical environment where new planets may eventually form.

Researchers combined multi-epoch X-ray and optical observations with data from the James Webb Space Telescope to model the disk's behavior. They found that the intensity of molecular emissions, including water and carbon dioxide, fluctuates as the two stars orbit each other, reaching higher levels when the stars are closest together at a point called periastron. This variation is driven by the increased luminosity generated by the stars as they pull in surrounding material.

While routine changes in stellar activity cause only minor structural shifts in the disk, they are sufficient to push the snowline—the distance from the star where volatile compounds like water can freeze into solid ice—outward by 17 percent. Simulations further suggest that while typical activity has little effect on certain molecular signals, intense X-ray flares significantly increase the brightness and abundance of specific ions like ionized argon and neon on the disk surface.

Key findings
- Molecular emissions of water and carbon dioxide are stronger at periastron due to higher accretion rates.
- Routine stellar variability causes the snowline to shift outward by 17 percent compared to the stars' furthest orbital point.
- X-ray flares significantly enhance the luminosity of hydrogen, argon, and neon in the disk surface.
- Observed line variability in disk-bearing systems matches models of moderately variable accretion and magnetospheric activity.

Scientific study

The Effect of X-Ray and Accretion Variability on Mid-Infrared Lines in the Young Disk-Bearing Binary DQ Tau (external link)