_Cacus.png) Shape model of Cacus from itslightcurve | |
| Discovery[1][2] | |
|---|---|
| Discovered by | H.-E. Schuster |
| Discovery site | La Silla Obs. |
| Discovery date | 8 February 1978 |
| Designations | |
| (161989) Cacus | |
Named after | Cacus(Roman mythology)[2] |
| 1978 CA | |
| Apollo · NEO · PHA[1] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 38.59 yr (14,096 days) |
| Aphelion | 1.3634AU |
| Perihelion | 0.8828 AU |
| 1.1231 AU | |
| Eccentricity | 0.2140 |
| 1.19yr (435 days) | |
| 345.40° | |
| 0° 49m 41.16s / day | |
| Inclination | 26.060° |
| 161.24° | |
| 102.16° | |
| Earth MOID | 0.0152 AU · 5.9LD |
| Physical characteristics | |
| 0.64±0.02 km[3] 1.126±0.073 km[4] 1.86 km[5] 1.9 km[6] | |
| 3.7538±0.0019 h[6] 3.756 h[7] 3.761 h[5] 3.77±0.11 h[8] | |
| 0.09[6] 0.119(derived)[6] 0.199±0.052[4] 0.46±0.09[3] | |
| Tholen =S[1][6] · Q[9] B–V = 0.910[1] U–B = 0.484[1] | |
| 16.58[6][7] · 17.1[4] · 17.2[1] · 17.32[5] · 17.43[3] | |
161989 Cacus (provisional designation:1978 CA) is a stonyasteroid, classified asnear-Earth object and apotentially hazardous asteroid of theApollo group, approximately 1 kilometer in diameter. It was discovered on 8 February 1978, by German astronomerHans-Emil Schuster atESO'sLa Silla Observatory in northern Chile.[2] Its orbit is confined betweenVenus andMars.
Thisminor planet was named from Roman mythology, afterCacus, a fire-breathing monster, which was killed byHercules.[2] The official naming citation was published by theMinor Planet Center on 24 November 2007 (M.P.C. 61270).[10]
| Date | JPL SBDB nominal geocentric distance | uncertainty region (3-sigma) |
|---|---|---|
| 1941-09-02 | 2418754 km | ± 6 km |
| 2022-09-01 | 8607710 km | ± 21 km[11] |
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