2022RNAAS...6...27L

We suggest that the recently discovered, enigmatic pulsar with a period of 18.18 minutes, GLEAM-X J162759.5-523504.3, is most likely a hot subdwarf (proto white dwarf). A magnetic dipole model explains the observed period and period-derivative for a highly magnetized (∼10⁸ G), hot subdwarf of typical mass ∼0.5M_⊙ and radius ∼0.3R_⊙, and an age of ∼3 × 10⁴ yr. The subdwarf spin is close to its breakup speed and its spindown luminosity is near its Eddington limit, likely as a result of accretion from a companion.