2025 PN7
| 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 small near-Earth asteroid and the most recently discovered quasi-satellite of Earth. First observed on 2 August 2025 by the Pan-STARRS 1 telescope at Haleakala Observatory in Hawaii, 2025 PN7 is a member of the Arjuna asteroid group—near-Earth objects with orbits very similar to Earth's.
Discovery
[edit]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 until 2083. Its small size and faint magnitude (H = 26.4) made it difficult to detect until high-precision surveys were conducted.[2]
Orbit and classification
[edit]
2025 PN7 is an Apollo asteroid with a semi-major axis of 1.003 AU, an orbital eccentricity of 0.108, and an orbital inclination of approximately 2°, placing it in the low-eccentricity, low-inclination Arjuna class. Unlike Earth's natural satellite, the Moon, 2025 PN7 is not gravitationally bound to Earth. It maintains a 1:1 mean-motion resonance with Earth, making it a quasi-satellite. From Earth's perspective, the asteroid appears to hover nearby.[3]
Relationship to Earth
[edit]2025 PN7 joins a small group of known quasi-satellites of Earth, including 164207 Cardea, 469219 Kamo‘oalewa, (277810) 2006 FV35, 2013 LX28, 2014 OL339, and 2023 FW13. Quasi-satellites like 2025 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 and horseshoe orbits due to gravitational perturbations.[5]
Physical characteristics
[edit]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]
Scientific significance
[edit]As a quasi-satellite, 2025 PN7 provides a natural laboratory for studying orbital 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 of planetary defense, asteroid mining, and solar system formation.[6]
See also
[edit]- Temporary satellite – objects that become temporarily gravitationally bound to a planet before later escaping
References
[edit]- ^ a b "(2025 PN7)". JPL Small-Body Database. NASA/Jet Propulsion Laboratory. Retrieved 25 October 2025.
{{cite web}}: CS1 maint: url-status (link) - ^ de la Fuente Marcos, Carlos; de la Fuente Marcos, Raúl (5 September 2025). "Meet Arjuna 2025 PN 7, the Newest Quasi-satellite of Earth". Research Notes of the AAS. 9 (9): 235. doi:10.3847/2515-5172/ae028f. ISSN 2515-5172.
- ^ Mukunth, Vasudevan (19 September 2025). "Arjuna asteroid 2025 PN7 is earth's latest quasi-satellite". The Hindu.
- ^ Gough, Evan (16 September 2025). "Earth Has Another Quasi-Satellite: The Asteroid Arjuna 2025 PN7". Universe Today.
- ^ Strickland, Ashley (16 September 2025). "Astronomers discover previously unknown quasi-moon near Earth". CNN.
- ^ Kasal, Krystal (10 September 2025). Lock, Lisa; Egan, Robert (eds.). "Scientists find quasi-moon orbiting the Earth for the last 60 years—and it's not the first one". Phys.org.
