Background
Earlier this year, a claim circulated that an object nicknamed “Phoebe” might represent a lunar‑mass primordial black hole, based on observations taken with the Dark Energy Camera (DECam) at the Cerro Tololo Inter‑American Observatory.
New Study
Researchers have re‑examined the DECam data and found that the object's luminosity changes over time in a pattern consistent with known variable stars. Their analysis incorporated photometric measurements and comparison with nearby stellar sources to rule out instrumental effects.
Findings
The results, posted to the arXiv preprint server on June 17, conclude that there is no evidence supporting the presence of a primordial black hole. Instead, the observed behavior can be fully explained by natural brightness variability, a common characteristic among many stars.
Implications
This outcome underscores the necessity of rigorous data interpretation before proposing exotic astrophysical objects. While the search for primordial black holes remains an active area of research, this case illustrates that apparent anomalies often have conventional explanations.
Future Work
The authors suggest that future candidates for primordial black holes be examined with multiple instruments and long‑term light‑curve monitoring to avoid similar misidentifications.