Magnetic and photometric variability of the super-slowly rotating Ap star GY And (HD 9996)

The star GY And (HD 9996) belongs to a very rare and poorly studied class of super-slowly rotating Ap (ssrAp) stars. The main difficulty in conducting studies of such stars is their unusually long periods, often amounting to tens or even hundreds of years. Based on long-term magnetic monitoring conducted at the 1-m telescope of the SAO RAS and photometric monitoring carried out at the 60-cm telescope of the Southern Station of the SAI, the period (which is just over 23 years) and the parameters of magnetic and photometric variability of GY And (HD 9996) have been clarified.