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arXiv · 2606.19442

Eppur non si trovano Vol. 3: Phoebe -- a Mirage of a Primordial Black Hole

Andrzej Udalski·Przemek Mróz
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Abstract

Recent preprints by Key et al. reported the discovery of a short-lived brightening of a star (nicknamed "Phoebe") located in the Large Magellanic Cloud that was interpreted as a short-timescale gravitational microlensing event produced by a lunar-mass primordial black hole (PBH) in the Milky Way dark matter halo. Here, we present an independent re-analysis of the publicly available DECam observations of this object, incorporating additional data from 2020 and 2021. The object underwent at least three distinct, low-amplitude brightenings (one of which was misinterpreted as a short-timescale microlensing event) in addition to long-term variations of its mean magnitude. These characteristics indicate that Phoebe is an ordinary variable star rather than a microlensing event. This finding resolves the apparent tension with the results from earlier microlensing experiments that rule out the hypothesis that a substantial fraction of dark matter is composed of lunar- and planetary-mass PBHs.

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Andrzej Udalski, Przemek Mróz. 2026-06-17. Eppur non si trovano Vol. 3: Phoebe -- a Mirage of a Primordial Black Hole. https://arxiv.org/abs/2606.19442

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