Massive stars (M > 8 solar masses) significantly affect the surrounding medium during their life through stellar winds and ionising radiation. These processes shape the circumstellar medium (CSM) into complex structures, including cavities. When a massive star explodes as a supernova (SN), the resulting shock wave expands into this non-uniform medium, generating bright X-ray emission. As a result, X-ray observations of SN remnants (SNRs) provide insights into the stellar evolution of a progenitor massive star and the interstellar medium (ISM) nearby.
RCW 103 is a young (∼2000 years) Galactic SNR that has begun interacting with its CSM. Despite evidence of an initially asymmetric density distribution at the explosion site, its observed X-ray morphology appears almost circular with a slight asymmetry towards the southwest. The cause of this morphology remains unclear. To explore this, we perform 3D (magneto-)hydrodynamic simulations using the FLASH code, incorporating radiative cooling and self-consistent treatment of X-ray emission.
We simulate the evolution of a massive star (18 M solar masses) in a uniform ISM, including the effects of ionising radiation and stellar winds. After the SN event, we track the shock propagation and X-ray emission across multiple energy bands, similar to Chandra observations. An example of synthetic X-ray maps in the corresponding energy bands is shown in Figure 1. As the progenitor star is not stationary, the stellar wind cavity is asymmetrical, leading to a brighter X-ray emission at the edges.
This is an ongoing project that focuses on identifying the primary reason responsible for the morphology in RCW 103’s X-ray emission. Possible explanations include the progenitor star’s runaway velocity, which caused a bow shock to form, the influence of interstellar magnetic fields, or a nearby molecular cloud. Modelling these effects will improve our understanding of SNR-ISM interaction.