Near-Earth Object (NEO) Close Approach Report & Asteroid Profile Potentially Hazardous Asteroid 2026 GU
Written by: Astrophyzix Digital Observatory
Introduction
Asteroid (2026 GU) is an Amor-class near-Earth object (NEO) classified as a Potentially Hazardous Asteroid (PHA) based on its size and orbital proximity to Earth. The object was observed over a short 5-day arc in this week and its orbit is currently defined by the initial JPL solution (Solution 1 on 09 April 2026.)
Despite its PHA classification, current orbital solutions indicate a relatively distant Earth flyby on 14 April 2026. Continued observations are required to refine its trajectory due to the limited observational baseline and elevated uncertainty level.
Key Takeaways
- Close approach on 2026-Apr-14 at ~0.09884 AU.
- Equivalent to approximately 38.4 lunar distances (~14.8 million km).
- Classified as a Potentially Hazardous Asteroid (PHA).
- Estimated diameter: ~150–300 meters (based on H magnitude).
- Orbit currently constrained using 90 observations over 5 days.
- Condition code 8 indicates high orbital uncertainty.
- No impact threat identified.
Scientific Consensus Snapshot
The current orbital solution for (2026 GU) is based on a short observational arc and remains subject to refinement. While the object's classification as a PHA reflects its long-term orbital geometry, the 14 April 2026 encounter is well outside any hazardous threshold. Future observations will reduce uncertainties and improve long-term trajectory modelling.
Asteroid Profile
| Parameter | Value |
|---|---|
| Object | (2026 GU) |
| Classification | Amor [NEO, PHA] |
| SPK-ID | 54607524 |
| Absolute Magnitude (H) | 21.307 |
| Estimated Diameter | ~150–300 meters |
| Condition Code | 8 (high uncertainty) |
| Observation Arc | 5 days |
| Observations Used | 90 |
| Earth MOID | 0.03619 AU (~5.41 million km) |
Orbital Characteristics
- Semi-major axis (a): 1.86222 AU
- Eccentricity (e): 0.4479
- Inclination (i): 17.86°
- Perihelion (q): 1.028 AU (just outside Earth's orbit)
- Aphelion (Q): 2.696 AU
- Orbital Period: ~928 days (~2.54 years)
- Mean Motion: 0.3878°/day
- Tisserand Parameter (Jupiter): 3.812
As an Amor-class asteroid, (2026 GU) does not currently cross Earth's orbit but approaches it from outside. Its relatively high inclination (~18°) suggests a dynamically evolved orbit, likely influenced by past gravitational interactions.
Close Approach Analysis (2026)
| Date (TDB) | Distance (AU) | Distance (LD) | Velocity (km/s) | Uncertainty |
|---|---|---|---|---|
| 2026-Apr-14 | 0.09884 | ~38.4 LD | Not specified | ± 7 minutes |
Astrophyzix Risk Index® (ARI)
ARI Score for (2026 GU) at Time of Report
- Current ARI Score based on live data: 41 / 100
- ARI Classification Band: Elevated
- Click here for Live Monitoring
Interpretation
An ARI score of 41 places (2026 GU) within the Elevated category. This reflects a combination of moderate size and its classification as a potentially hazardous asteroid (PHA), despite its relatively large miss distance during the 2026 encounter.
The score indicates increased observational significance, but does not imply any impact risk. The elevated rating is primarily driven by intrinsic object characteristics rather than encounter proximity.
Score Drivers
- Miss Distance (~38.4 LD): Strongly reduces score via exponential decay
- Estimated Size (~150–300 m): Significant contribution to total score
- PHA Classification: +18 point bonus applied
- Velocity: Not available in dataset (not included in score contribution)
ARI Scale Overview
| Score Range | Category | Operational Meaning |
|---|---|---|
| 0–20 | Low | Routine flyby; minimal observational priority |
| 21–40 | Moderate | Notable object; standard monitoring |
| 41–60 | Elevated | High-interest object driven by size, proximity, or classification |
| 61–80 | High | Close approach and/or large object requiring active tracking |
| 81–100 | Critical | Extreme proximity or uncertainty; priority observational target |
Methodology (ARI v2)
The Astrophyzix Risk Index® (ARI) is a non-official heuristic index developed for educational and visualisation purposes. It is not affiliated with, nor a substitute for, formal hazard assessment systems such as the Palermo or Torino scales used by NASA and ESA.
| Component | Weight | Formula / Description |
|---|---|---|
| Miss Distance | Up to 40 pts | 40 × e(-0.1386 × missLD) (exponential decay; half-life = 5 LD) |
| Relative Velocity | Up to 20 pts | min(20, 10 × log10(velocity km/s)) |
| Estimated Diameter | Up to 20 pts | min(20, diameter (m) × 0.05) |
| PHA Classification | +18 pts | Applied if object meets NASA PHA criteria |
Miss distance is expressed in Lunar Distances (LD), where 1 LD = 384,400 km. ARI scores are dynamically calculated using live orbital data (NASA CNEOS NeoWs API) and are not stored as predictive metrics. Live ARI Score will change as new data is received and analysed by our Live NEO PHA Monitoring system
Limitations
- Does not incorporate orbital covariance or uncertainty propagation
- Does not model n-body gravitational perturbations
- Does not represent impact probability
- Velocity term reflects impact energy potential, not likelihood
- ARI Documentation available here Astrophyzix Risk Index Documents
ARI® v2 is protected under international copyright. Educational use only.
2026 Relevance
The April 2026 close approach of (2026 GU) is observationally significant due to the object's size and classification as a PHA, but it does not represent a close pass in planetary defence terms. At nearly 40 lunar distances, the asteroid remains well outside any region of concern.
However, due to its short observational arc and condition code 8, this encounter provides an important opportunity for follow-up observations to improve orbit determination and reduce long-term uncertainty.
Risk Assessment
- PHA classification is based on size and orbital geometry, not immediate threat.
- No impact scenarios are identified in current datasets.
- Large miss distance provides a substantial safety margin.
- High condition code indicates need for further tracking.
Conclusion
Asteroid (2026 GU) is a moderately large near-Earth object with a dynamically interesting orbit and PHA classification. The April 2026 encounter is distant and poses no risk, but the object remains a target for continued observation due to its current orbital uncertainty.
Future observations will be critical in refining its orbit and improving long-term hazard assessment, particularly given its relatively large size compared to typical newly discovered NEOs.
Sources
- NASA JPL Small-Body Database – (2026 GU)
- JPL Horizons Ephemeris (SPKID: 54607524)
- NASA CNEOS Close Approach Database
- Astrophyzix NEO Monitoring Systems and Astrophyzix Risk Index