(161989) Cacus Apollo
Discovered on 8 February 1978 by H.-E. Schuster at La Silla.
The fire-breathing monster Cacus, son of Vulcan, stole cattle Hercules had acquired as his tenth labor. Although Cacus tried to make it appear that the cattle had gone in the opposite direction, Hercules found them and strangled Cacus, erecting an altar at the spot that later became the Forum Boarium, the Rome cattle market.Naming citation (20071124/MPCPages.arc), IAU / Minor Planet Center, via NASA/JPL
Where Cacus is today
Seen from above the solar system on 2026-10-14: Cacus is 1.32 au from the Sun and 1.70 au from Earth. Computed from JPL's orbital elements.
Facts
| Number | 161989 |
| Provisional designation | 1978 CA |
| Orbit class | Apollo · near-Earth · potentially hazardous |
| Diameter | 1.90 km (#17,152 largest of 17,440 named asteroids with a measured size) |
| Albedo | 0.0900 |
| Rotation period | 3.75 hours |
| Spectral type | S |
| Absolute magnitude (H) | 17.31 |
| Orbital period | 1.19 years |
| Semi-major axis | 1.12 au |
| Perihelion – aphelion | 0.883 – 1.36 au |
| Eccentricity | 0.214 |
| Inclination | 26.1° |
| Closest distance between its orbit and Earth's (MOID) | 0.0146 au |
Data: NASA/JPL Small-Body Database and the IAU Minor Planet Center.