Asteroid 242708 (2005 UK1): A Close-Approach Apollo-Class Near-Earth Object
Image Credit: Spacereference
Asteroid 242708 (2005 UK1) is a noteworthy near-Earth asteroid (NEA) that has drawn attention from astronomers due to its Earth-crossing orbit and classification as a Potentially Hazardous Asteroid (PHA). Its trajectory brings it relatively close to our planet on cosmic scales, and its size and orbit make it an object of scientific interest in ongoing Near-Earth Object monitoring efforts.
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Discovery and Classification
- Designation: 242708
- Provisional Name: 2005 UK1
- Discovery Date: October 24, 2005
- Discovery Site: Mount Lemmon Survey, Arizona
- Orbital Class: Apollo (Earth-crossing orbit)
- NEA Status: Near-Earth Asteroid
- PHA Classification: Potentially Hazardous Asteroid
Apollo asteroids like 2005 UK1 have orbits that frequently intersect Earth’s orbit, and while that doesn’t guarantee an impact, it does bring these objects into a region where careful tracking is essential.
Orbital Dynamics and Characteristics
- Orbital Period: ~1,440 days (~3.94 years)
- Perihelion: ~0.76 AU
- Aphelion: ~4.24 AU
- Semi-Major Axis: ~2.50 AU
- Eccentricity: ~0.695 (highly elliptical)
- Inclination: ~0.79° relative to Earth’s orbital plane
These orbital parameters mean that 2005 UK1 travels from well inside Earth’s orbital distance to far beyond Mars’ orbit, crossing our path as it journeys around the Sun.
Size, Rotation, and Physical Properties
- Estimated Diameter: ~0.632–1.413 km
- Average Diameter: ~0.8 km
- Rotation Period: ~63.80 hours
- Absolute Magnitude: ~18.1
At roughly 0.8 km in diameter on average, this asteroid is larger than about 97% of known near-Earth objects, though still small compared with the largest asteroids in the Solar System.
Close Approaches to Earth
- Jan 12, 2026: ~12,355,836 km · ~14.4 km/s
- Dec 24, 2029: ~23,083,974 km · ~21.5 km/s
- May 25, 2101: ~23,210,230 km · ~21.4 km/s
- Apr 29, 2105: ~18,250,115 km · ~13.6 km/s
- Jan 21, 2113: ~19,452,075 km · ~13.3 km/s
- Dec 25, 2116: ~23,228,359 km · ~21.5 km/s
- May 19, 2188: ~8,897,335 km · ~18.5 km/s
- Apr 19, 2192: ~24,639,280 km · ~13.1 km/s
All of these distances are still many times greater than the Moon’s orbital distance (~384,000 km), underscoring that while the asteroid comes near Earth in orbital terms, it doesn’t approach closely enough to pose an imminent impact threat.
Observation History and Tracking
- Observation Arc: 2005 – present
- Number of Observations: Hundreds of follow-ups
- Last Recorded Observation: June 3, 2022
These observations allow scientists to refine its orbit and predict future paths very accurately. Because the orbit is so well known, we can confidently list future close approaches decades into the future.
Exploration Considerations
Although this asteroid is scientifically interesting, it is not currently considered a feasible target for human or robotic exploration under existing mission design studies such as NASA’s Near-Earth Object Human Space Flight Accessible Targets Study (NHATS).
The combination of its orbit and distance at closest approach makes it unsuitable for low-delta-V missions in the foreseeable future.
Why It Matters
- Improves orbital modeling accuracy
- Tests planetary defense detection systems
- Advances understanding of asteroid composition and dynamics
- Supports long-term mitigation planning for potential hazards
In doing so, objects such as 2005 UK1 help refine our knowledge of the Solar System’s small body population and inform global efforts to safeguard Earth.
