| Discovery | |
|---|---|
| Discovered by | Pan-STARRS 1 |
| Discovery date | 2 August 2025 |
| Orbital characteristics[1] | |
| Epoch 21 November 2025 (JD 2461000.5) | |
| Uncertainty parameter 0 | |
| Aphelion | 1.109 AU |
| Perihelion | 0.893 AU |
| 1.001 AU | |
| Eccentricity | 0.108 |
| 1.002 yr (365.799 d) | |
| 217.230° | |
| Inclination | 1.98° |
| 112.25° | |
| 79.888° | |
| Physical characteristics | |
| Dimensions | ~19 m |
| 26.36 (JPL)[1] | |
2025 PN7 is a smallnear-Earth asteroid and the most recently discoveredquasi-satellite of Earth. First observed on 2 August 2025 by thePan-STARRS 1 telescope atHaleakala Observatory in Hawaii,2025 PN7 is a member of theArjuna asteroid group—near-Earth objects with orbits very similar toEarth's.
2025 PN7 was detected by the Pan-STARRS survey, with archival observations later confirming its presence in images dating back to 2014. Analysis indicated that the asteroid has been in a quasi-satellite configuration with Earth for at least 60 years and is expected to remain in this resonant state for approximately 128 years. Its small size and faint magnitude (H = 26.4) made it difficult to detect until high-precision surveys were conducted.[2]
2025 PN7 is anApollo asteroid with asemi-major axis of 1.003 AU, anorbital eccentricity of 0.108, and anorbital inclination of approximately 2°, placing it in the low-eccentricity, low-inclination Arjuna class. Unlike Earth's natural satellite, theMoon,2025 PN7 is not gravitationally bound to Earth. It maintains a 1:1mean-motion resonance with Earth, making it a quasi-satellite. From Earth's perspective, the asteroid appears to hover nearby.[3]
2025 PN7 joins a small group of known quasi-satellites of Earth, including164207 Cardea,469219 Kamo‘oalewa,(277810) 2006 FV35,2013 LX28,2014 OL339, and2023 FW13. Quasi-satellites like2025 PN7 are temporarily co-orbital with Earth but are not true moons. Some Arjuna-class asteroids with particularly Earth-like orbits can occasionally become temporary mini-moons, gravitationally captured by Earth for months to years.[4]
During its closest approach,2025 PN7 comes within approximately 299,000 km of Earth, while at its farthest it can be tens of millions of kilometers away. Over time, it may transition between quasi-satellite andhorseshoe orbits due to gravitational perturbations.[5]
The asteroid is estimated to be approximately 19 meters (62 feet) in diameter. Due to its small size and faint surface, little is known about its composition or albedo. It is assumed to be a rocky, natural object, though more observations are needed to confirm its surface properties.[citation needed]
As a quasi-satellite,2025 PN7 provides a natural laboratory for studyingorbital resonances and near-Earth asteroid dynamics. Its relatively stable orbit, close to Earth, makes it an accessible target for future spacecraft missions, potentially including studies ofplanetary defense,asteroid mining, andsolar system formation.[6]
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