Determine the rotation period of asteroid 3173

Determine the rotation period of asteroid 3173 (McNaught), including whether its observed long-period variation corresponds to a rotation period near 572 or 1143 hours or instead reflects changing photometric offsets, blending, synodic–sidereal effects, or non-principal-axis rotation.

Background

Asteroid 3173 exhibits strong photometric variations at approximately 572 and 1143 hours, while peaks near 46 and 50 hours appear to be daily aliases of the slower variation. TESS observations suppress the short-period peaks and support the existence of a slow brightness change, but the data do not establish whether the variation is rotational or caused by systematic effects such as changing offsets or blending.

The interpretation is further complicated by the choice between single- and double-peaked light curves, the difference between synodic and sidereal periods over the long observational baseline, and possible non-principal-axis rotation. Consequently, no rotation period is adopted.

References

Therefore, the $45.98$ hour period in Table~\ref{tab:results} is only the strongest candidate of the 0.5-240 hour search, and it is probably not the rotation period. The rotation period of 3173 remains undetermined and may be much longer.

— Combination of multi-observatory photometry to determine asteroid rotation periods  (2610.13223 - Nagainis et al., 9 Oct 2026) in Section 3, subsection “(3173) McNaught”