2026 HZ4 is the 62nd known asteroid to pass within 1 lunar distance of Earth since the start of the year and the second closest so far, after 2026 EM on March 7 at 0.077 LD.
The object was initially reported by Catalina Sky Survey on April 24, but the earliest listed observation in the MPC data was made by Palomar Mountain–ZTF at 08:09 UTC on April 23, about 28 hours before closest approach.
2024 HZ4 belongs to the Apollo group of asteroids, a class of near-Earth objects whose orbits cross Earth’s path, and has an estimated diameter between 3 and 6.7 m (9.8-22 feet). CNEOS lists the asteroid’s absolute magnitude at 29.7.
Its flyby took place at a relative velocity of 13.27 km/s at 12:13 UTC on April 24. 2026 HZ4’s closest approach was about 23 338 km (14 501 miles) above Earth’s surface — well inside geostationary orbit, which lies about 35 780 km (22 230 miles) above Earth’s equator.
The current JPL orbit solution is based on just 14 observations over a 1-day data arc, with a condition code of 8. MPC also lists the orbit uncertainty as 8.
Based on JPL orbital elements for epoch April 24, 2026, HZ4 has a semimajor axis of 2.0047 AU, eccentricity of 0.5259, inclination of 13.44°, perihelion distance of 0.9505 AU, and aphelion distance of 3.0589 AU. Its orbital period is about 2.84 years.
References:
1 Asteroid 2026 HZ4 – CNEOS – Accessed April 27, 2026
2 Asteroid 2026 HZ4 – Minor Planet Center – Accessed April 27, 2026