Accretion onto WD 2226$-$210, the central star of the Helix Nebula

S. Estrada-Dorado, M. A. Guerrero, J. A. Toalá +4

The central star of the Helix Nebula, WD 2226$-$210 presents enigmatic hard X-ray emission and mid-IR excess. The latter has been attributed to a dusty disk or a cloud-like structu…