AB Aurigae

One of the largest stars in the Taurus-Auriga star forming cloud, AB Aurigae is a young star (2 - 4 million years old), surrounded by a disk of dust. Knots of material in the disk may well represent an early stage of a process which could result in the formation of planets over the next few million years.

Protoplanetary disk

The swirling circumstellar disk is large, about 30 times the size of a standard solar system. It is believed planet-making is just beginning in AB Aurigae's disk because known disks surrounding younger stars (less than 1 million years old) do not show such clumpy structure, while disks of slightly older stars (aged 8-10 million years) have gaps and features suggesting that planets have already been formed.

Anomalous X-ray emissions

AB Aurigae is also an anomalous X-ray source. Initially the presence of a companion star was suggested to explain these emissions, but the temperature of the gas producing the rays was too low to be a newborn star. Eventually, it was discovered the X-rays are actually coming from a region just above the star. It appears that material cast off by the star by its two hemispheres are being collided together by its magnetic field. It's where the solar wind is colliding that the X-rays are being generated.