 | This article needs to be updated. (August 2026) |
The Koronis or Koronian family (FIN: 605), also known as the Lacrimosa family,: 16 is a very large asteroid family of stony asteroids, located in the outer region of the asteroid belt. They are thought to have been formed at least two billion years ago in a catastrophic collision between two larger bodies. The family is named after its lowest-numbered member 158 Koronis, and the largest known member (208 Lacrimosa) is about 41 km (25 mi) in diameter. Koronis family members travel in independent heliocentric orbits which share similar semimajor axes, eccentricities, and inclinations, but the asteroids themselves are not physically clustered in space. The spin poles of several of the large members do appear to be aligned in space. The family has at least 5949 members.
This family has two subfamilies. The Karin family (FIN: 610) was formed remarkably recently in a catastrophic collision (destroying the parent body), with an estimated age of 5.72 million years. The Koronis(2) family (FIN: 621) with 246 members is the other. It formed 15 million years ago by a non-catastrophic collision with 158 Koronis.
On August 28, 1993, the Galileo spacecraft visited a member of this family, 243 Ida. A photo of Ida (and its tiny moon Dactyl) is part of the composite image at right (numbered 243).
