The duration carried by dust
Dust around P/2026 N2 is visible on both sides of its closest approach to the Sun. From the late-June Rubin image to the October Keck observation, the span is 102 days: long enough to distinguish more than a single moment of activity in a Main Belt object, yet insufficient to say that we saw everything in between. In the new preprint, which has not undergone peer review, those two limits meet within the same observation. The distance between a comet’s appearance and the mechanism driving it is measured here in time.[1]
June and July LSST images and the 7 October LRIS observation on Keck I show a core broader than field stars. But the light reaching a telescope depends on more than dust: distance from the Sun, distance from us and illumination angle all change. After correcting these effects, i-band light from approximately matched physical regions remains nearly unchanged between 9 July and 7 October. Absolute magnitude moves from 19.04 ± 0.05 to 18.97 ± 0.05. The later brightening of 0.07 ± 0.07 magnitude is as small as its uncertainty. The comparison therefore describes approximate stability, rather than a confidently measured increase.[1]
The constraint on an activity model comes from the persistence of comparable corrected brightness at widely separated dates around perihelion. A mechanism must account for more than one photograph of dust. Ice sublimation driven by solar heating is compatible with that behaviour. Compatibility is not a detection of water. Slowly escaping dust released in one event can remain visible, and repeated rotational shedding can supply fresh material. The observation does not independently confirm these explanations; it sets a timescale that each must accommodate. The model contest remains attached to what the light can actually distinguish.[1]
The possibilities left by missing days
There is an 85-day gap in the middle of the timeline. Between the final LSST image and the day Keck observed, activity could have diminished and resumed without being seen. A 102-day observational span is therefore not 102 days of continuously demonstrated dust production. Similar values of the dust proxy Afρ are not a wholly independent second confirmation either: that quantity is derived from the same photometry. Converting the same photons into another useful measure cannot recover the missing days. The gap preserves room for both sustained activity and episodes whose separation the images do not resolve.[1]
Colour does not close this distinction on its own. Neutral colours are compatible with B- or C-type asteroids, but the observed light combines nucleus and dust; it is not a spectral signature of water. A 2021 DECam image recovered to examine an earlier passage is compromised by a nearby star. It cannot securely establish either activity or inactivity at that epoch. An archival image reaches into the past only as far as its signal can be separated. It does not yet supply the repeated behaviour that would strengthen a seasonal explanation.[1]
What changes for me is the time interval through which competing explanations must now pass, rather than a seal placed on the presence of ice. Activity appears at both ends; observations are absent in between; the age of the visible dust remains unresolved. More closely spaced images and a model following dust motion could help distinguish material left by one event from a continuously replenished tail. Comparable behaviour at another perihelion passage could also change the comparison. For now the question we can responsibly ask the sky remains narrow: does activity return at the same orbital phase?[1]