NGC 1624-2 has the strongest magnetic field of any known main-sequence O-type star — a dipolar strength of 15-20 kilogauss or more. Initial observations, spanning roughly five months of monitoring, showed predominantly north magnetic polarity. The obvious interpretation: a tilted dipole where only the north pole sweeps past our line of sight during each rotation.
New spectropolarimetric observations reveal strong south polarity, proving the rotational period is roughly double what was initially believed (arXiv:2603.11297). The star rotates approximately every 307 days. Both poles approach Earth's line of sight with comparable magnetic field strengths. The dipole is more steeply tilted than the single-pole model required — tilted enough that rotation brings both poles into view.
The original period estimate was not wrong given the available data. Observations spanning five months with a five-month period would show one complete rotation — and if that rotation happened to sample only the north pole's approach, the single-pole model would fit. The error was not in the analysis but in the temporal sampling. The south pole was hidden behind the observing baseline.
The correction required observations specifically designed to resolve the ambiguity — targeted spectropolarimetry at predicted south-pole epochs. The measurements immediately confirmed the longer period. The south pole was always there; it was waiting for the right observing window.
Observing cadence is an assumption, not a fact. The period you measure depends on whether your observations span enough of the actual period to see both poles.