NEO Close Approach Report by Astrophyzix Digital Observatory
Introduction
Earth’s near‑space environment is currently hosting a cluster of scientifically notable—but safely distant—close approaches from three Apollo‑class near‑Earth asteroids: 2004 XA45, 2018 EW1, and 2018 JN1. While none of these objects meet Potentially Hazardous Asteroid criteria, each encounter provides a valuable snapshot of NEO population behaviour across a wide range of sizes, velocities, and orbital histories. Their passages highlight the diversity of objects that routinely move through the inner Solar System: from sub‑30‑meter bodies comparable to the Chelyabinsk airburst to multi‑hundred‑meter asteroids large enough to represent regional‑scale impactors under different orbital circumstances.
These approaches also illustrate the importance of continuous survey coverage. All three asteroids have well‑constrained orbits derived from multi‑year observation arcs, enabling precise predictions of their trajectories and confirming that each will pass Earth at large, interplanetary distances—tens to hundreds of lunar distances away. Their varying encounter velocities, from the unusually high‑energy passage of 2004 XA45 to the comparatively slow drift of 2018 EW1, further demonstrate the dynamical diversity within the Apollo-class NEO population.
The following sections provide a detailed breakdown of each object’s physical characteristics, approach geometry, orbital classification, and risk context, forming a concise situational overview of this multi‑object close‑approach window.
Asteroid 2004 XA45Outlook and Analysis
- Physical profile. Estimated at 168 to 375 meters across (mean about 271 m), comparable in scale to a small office tower. At H 21 this is a faint object requiring a large telescope and CCD or CMOS imaging to detect, beyond visual observation.
- Approach geometry. Miss distance is 68,753,396 km (178.78 lunar distances, 0.45959 AU); this is far beyond the Earth-Moon system, in interplanetary space. Relative velocity is 31.26 km/s; this is exceptionally fast, comparable to the orbital speed of Earth around the Sun, indicating a high-energy retrograde or steeply inclined orbit. The closest approach is happening within the hour
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- Orbital character and risk. Its orbit is classified as Apollo, meaning it crosses the orbit of Earth from outside; this is the most common NEO orbit type. This object has been tracked since 2004, with 44 recorded observations contributing to its orbital fit, giving an observation arc spanning roughly 1410 days. It does not meet PHA criteria because its minimum orbit intersection distance with Earth exceeds 0.05 AU, despite its substantial size. No reported impact Risk.
Asteroid 2018 EW1Outlook and Analysis
- Physical profile. Estimated at 15 to 33 meters across (mean about 24 m), similar in scale to the Chelyabinsk meteor that exploded over Russia in 2013 (about 20 meters). With H 26.3, this object is intrinsically very faint and only detectable with professional-grade survey telescopes.
- Approach geometry. Miss distance is 63,181,204 km (164.29 lunar distances, 0.42234 AU); this is far beyond the Earth-Moon system, in interplanetary space. Relative velocity is 7.34 km/s; this is on the slower end for near-earth objects, comparable to or below the orbital speed of the International Space Station (about 7.7 km/s). The closest approach occurs in approximately 15 hours..
- Orbital character and risk. Its orbit is classified as Apollo, meaning it crosses the orbit of Earth from outside; this is the most common NEO orbit type. This object has been tracked since 2018, with 74 recorded observations contributing to its orbital fit, giving an observation arc spanning roughly 11 days. It does not meet PHA criteria primarily because its size is below the 140-meter threshold; even an atmospheric entry of an object this size would produce a localized airburst rather than ground damage on a regional scale. No reported impact Risk.
Asteroid 2018 JN1
Outlook and AnalysisPhysical profile. Estimated at 92 to 206 meters across (mean about 149 m), roughly the length of a football field or a large airliner. At H 22.3 this is a faint object requiring a large telescope and CCD or CMOS imaging to detect, beyond visual observation.
Approach geometry. Miss distance is 27,056,382 km (70.35 lunar distances, 0.18086 AU); this is far beyond the Earth-Moon system, in interplanetary space. Relative velocity is 13.7 km/s; this is typical for NEO close approaches, near the average encounter speed. The closest approach occurs in approximately 19 hours.
Orbital character and risk. Its orbit is classified as Apollo, meaning it crosses the orbit of Earth from outside; this is the most common NEO orbit type. This object has been tracked since 2018, with 96 recorded observations contributing to its orbital fit, giving an observation arc spanning roughly 2909 days. It does not meet PHA criteria because its minimum orbit intersection distance with Earth exceeds 0.05 AU, despite its substantial size. No reported impact risk.