Chemical map of AB Aurigae reveals how planet formation alters surrounding material

Star system: AB Aurigae | Distance from the Sun: 509 light years

AB Aurigae is a young star surrounded by a protoplanetary disk—a rotating ring of gas and dust where planets are currently forming. Recent observations have mapped the chemical composition of this disk, finding that molecules are not spread evenly. Instead, certain chemicals concentrate in specific areas, suggesting that both external material falling into the disk and the birth of new planets significantly shape its internal environment.

Researchers used the NOEMA observatory to capture 1.2 millimeter radio waves from the disk. This allowed them to measure the distribution of different gases, such as sulfur monoxide (SO) and various hydrocarbons. They found that SO emission is stronger in the northern part of the disk, where material is actively falling in from space, while other molecules like C2H are concentrated in the south.

These patterns indicate that different physical processes, such as heating from infalling material or intense radiation from forming planets, drive chemical changes. By analyzing the temperatures and densities of these gases, the study shows that the disk is chemically diverse, which may eventually influence the final chemical makeup of any planets born within this system.

Key findings
- Sulfur monoxide is concentrated in the northern disk, likely due to material falling into the system.
- Hydrocarbon molecules peak in the southern disk, possibly driven by heat or radiation from young planets.
- Molecules like CS form a nearly symmetrical ring, suggesting they exist in different layers than the unevenly distributed gases.
- Gas-phase carbon-to-oxygen ratios appear to be high, indicating complex chemical processing during planet formation.

Scientific study

Azimuthal molecular variations in the AB Aur planet-forming disk (external link)