Summary

2026 JN4 was the twelfth asteroid discovered on an impact trajectory, and the first one in almost 1.5 years. It was the first imminent impactor found with the synthetic tracking technique, by JPL's SynTrack team in California, USA. It impacted our planet a bit more than 3 hours after discovery, in a still poorly determined area between Northern Australia and the island of Papua.

Discovery circumstances and follow-up

The discoverers immediately confirmed the object with their own second co-located facility. Additional follow-up from distant locations was attempted by various telescopes, but none succeeded. A prediscovery trail was later reported by the Zwicky Transient Factory, found in an image exposed about 2 hours before discovery.

Astrometric follow-up started appearing over the next few hours, first from stations in the United States and then from Asia. The object then entered Earth's shadow about 20 minutes before impact.

Trajectory in Space

In the video below, the vernal equinox points to the right side of the image. The view is tilted by approximately 30 degrees above the Ecliptic.

Trajectory Relative to the Earth

The video below shows the trajectory in space of 2026 JN4 in the hours prior to its impact with Earth.

2D Impact Corridor

The plot below shows the 5-sigma entry corridor on the ground, without including the atmospheric effects.

3D Impact Corridor

The highlighted area in the animation below represents the 1-σ (in red) and the 3-σ (in orange) fall area of the propagated object without including the atmospheric effects.

Atmospheric phase details 

The fireball occurred somewhere over the islands of Australia and New Guinea, and the surrounding waters. The impact corridor spans over more than 4500 km, with a minimal fraction covered by ground-based fireball detection cameras. It has not been detected by these cameras, or any other dedicated space-based or ground-based sensor (infrasound, seismometer, IR or lightning imager…). There is a witness of a bright fireball in Darwin that matches the time and direction expected for the entry of 2026 JN4, narrowing the impact corridor to the North of Australia’s Northern Territory. Unfortunately, there is no other independent testimony or signal record.

Search for meteorites

Due to the short observational arc, the impact corridor is exceptionally large, which prevents any meteorite search. Part of the impact corridor is over oceanic waters. The rest of it covers very remote inhabited areas, where casual finding is not expected.