Asteroid 1998 KY26 has turned out to be smaller and faster than expected following a new international observation campaign on near-Earth asteroidsData obtained with the Very Large Telescope (VLT) of the European Southern Observatory (ESO) show that the object measures around 11 meters in diameter and rotates on its axis in about five minutes.
These measurements, led by the astronomer Toni Santana-Ros (University of Alicante)They are finalizing the roadmap for JAXA's extended Hayabusa2 mission. The Japanese probe is scheduled to rendezvous with 1998 KY26 in 2031, in what will be the first visit to such a tiny asteroid by a spaceship.
What do we know now about 1998 KY26
The new image of the object reveals a diameter of around 11 meters (decametric size)almost three times smaller than previous estimates of around 30 meters. Furthermore, the rotation period is reduced to about five minutes, compared to the ten that were previously thought, confirming that it is indeed an asteroid. fast and extremely compact.
Observations point to a high-albedo surface, meaning it is relatively bright. This suggests that it could be a solid rock fragment originating from the rupture of a larger body, although it is not ruled out that it is a collection of loosely cohesive debris. Studies on samples and reflectance provide context, as shown by research on asteroid samples.
The scale of the 1998 KY26 is so small that its size is comparable to that of the Hayabusa2 probe itselfThis circumstance makes the meeting a technical and scientific milestone, with the possibility of studying in situ near-Earth objects of similar dimensions to some meteors relevant to planetary security.
Implications for the Hayabusa2 mission
Its small size and rapid rotation complicate any approach and contact maneuver. A brief touch-and-go would require very precise reaction times and extremely fine navigation, as highlighted by the authors of the study.
Hayabusa2 has already demonstrated its capabilities with 162173 Ryugu, about 900 meters in diameter, from which it brought samples back to Earth in 2020. With fuel reserves available, the spacecraft embarked on an extended mission whose ultimate goal is 1998 KY26, opening a new phase of exploration of very small asteroids.
Operational planning will benefit from these refined measures, which help to model the lighting, rotation dynamics, and environment of the asteroid; these aspects are addressed in works by scientific research and modeling on small bodies.
How the new measure was obtained
Due to its extremely low size and brightness, the team took advantage of a favorable close approach to Earth to observe it with large aperture telescopesincluding ESO's VLT in Atacama. The photometric signal, combined with previous data, including radar, allowed for adjustments to size, rotation period, and albedo. The use of opportunities to favorable approach to Earth It was key to capturing a sufficient signal.
This type of work requires coordination between distributed observatories and advanced analytical techniques. The result is a characterization detailed enough to reduce large uncertainties in an objective that, until now, was less well defined; improving surveillance and the catalog of NEAs is essential, as reflected in initiatives on the near-earth asteroids.
Importance for Spain and Europe
Scientific leadership from the University of Alicante And the use of European infrastructure such as the VLT underscores the role of Spain and Europe in small body exploration. These advances also fuel strategies for planetary defense by improving our ability to detect and assess risks associated with tiny but potentially dangerous objects.
Furthermore, the possibility of characterizing such small asteroids using ground-based means opens doors to future European missions and collaborations with JAXA and other agencies, including emerging fields such as in-situ resource extraction or technology demonstration campaigns.
The big questions that remain open
It remains to be determined whether 1998 KY26 is really monolithic or an aggregate of rubbleWhat mechanical properties does its surface exhibit, and how does its rapid rotation influence the material's stability? The Hayabusa2 visit will allow for close observation of phenomena that, until now, have only been modeled. The possible mitigation maneuvers and its limitations are a critical part of that knowledge.
Whatever the scenario, the encounter will provide critical data on the evolution of decametric-sized objects, their interaction with solar radiation, and their response to potential mitigation maneuvers or sampling in future missions.
With a measured size of about 11 meters, a rotation of approximately five minutes, and a high albedo, 1998 KY26 emerges as an ideal target for test new techniques navigation, characterization and study of near-Earth asteroids, consolidating the role of Spain and Europe in this line of research.
