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arXiv · 2610.17981

Physical characterization of Earth's quasi-satellite 2025 PN7

Grigori Fedorets·Zuri Gray·Mikael Granvik·Eric MacLennan
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Abstract

A hypothetical origin as lunar ejecta for Earth's quasi-satellites (QS) has gained initial support in recent years, but there is scarce photometric and/or spectroscopic data to support the premise due to the rare observational windows to obtain such data for these small objects. One of the key pieces of evidence supporting the lunar-origin hypothesis, the lunar-like, very red reflectance spectrum of QS (469219) Kamo'oalewa, was recently found to be flawed. We present reflectance spectroscopy of Earth's QS 2025~PN$_7$ obtained with FORS2 at UT1-Antu of the ESO Very Large Telescope. This is only the second QS that has ever been characterized, the first being (469219) Kamo'oalewa, the sample-return target of the Tianwen-2 mission. Our results indicate that 2025~PN$_7$ exhibits a near-solar, flat visual spectrum, most consistent with the B-type in the Bus-DeMeo taxonomy. Our results therefore still support an asteroid-belt origin for most of Earth's QSs. The lunar-ejecta hypothesis can only be formally rejected with a larger sample of spectroscopically characterized QSs.

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Grigori Fedorets, Zuri Gray, Mikael Granvik, Eric MacLennan. 2026-10-13. Physical characterization of Earth's quasi-satellite 2025 PN7. https://arxiv.org/abs/2610.17981

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