About Cacus
Cacus is an uncommon neo. It has spectral type S and swings within 0.883 AU of the Sun at perihelion.
An Apollo-class object: its orbit is wider than Earth's but crosses it. Most known Earth-crossers belong to this family.
Uncommon neo 33 EP
Cacus
Position computed live · sbdb
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Live ephemeris
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Score breakdown
· 5 badgesUncommon 34 pts → Rare
- Potentially hazardous +12
- Has a proper name +8
- Near-Earth object +5
- Apollo: crosses Earth's orbit +4
- Stony asteroid +4
Total score 33
1 more point to reach Rare.
Badges
- Near-Earth object · +5
- Potentially hazardous · +12
- Has a proper name · +8
- Apollo: crosses Earth's orbit · +4
- Stony asteroid · +4
Trivia
Handle with care
- What 'hazardous' means. 'Potentially hazardous' is bookkeeping, not a prediction: it means the orbit passes within 0.05 AU of Earth's and the body is big enough to matter. Nothing on that list is known to be on a collision course.
- If it ever hit. A rock this size arriving at a typical 20 km/s would release around 446.3 thousand megatons — enough to devastate a region the size of a small country.
What it actually is
- Its orbit family. An Apollo-class object: its orbit is wider than Earth's but crosses it. Most known Earth-crossers belong to this family.
- Closest approach. At its nearest it comes within 0.88 AU of the Sun — inside the orbit of Earth.
- One lap. A single orbit around the Sun takes it about 1.2 years.
- How far it roams. Its orbit swings between 0.88 and 1.36 AU from the Sun.
Sense of scale
- Sense of scale. In everyday terms it is roughly 0.2× the height of Mount Everest.
Standing on it
- Don't jump. Escape velocity here is only around 1.15 m/s. A determined jump would launch you off it and into your own orbit around the Sun.
Properties
- albedo
- 0.09
- aphelion au
- 1.36
- designation
- 161989
- diameter km
- 1.9
- eccentricity
- 0.2139
- full name
- 161989 Cacus (1978 CA)
- h mag
- 17.31
- inclination
- 26.07
- mean motion deg day
- 0.8286
- moid au
- 0.0146
- name
- Cacus
- named
- yes
- orbit class
- APO
- perihelion au
- 0.883
- pha
- yes
- rotation period h
- 3.7538
- semi major au
- 1.123
- spec taxonomy
- S
- spect
- S
How to see it
Like any astronomical target, Cacus is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. Because it moves against the background stars, the live position panel on this page tracks where it is right now. The visibility panel above works out tonight's viewing window for your saved location.
Why Cacus is an uncommon neo
Cacus scores 33 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 1 point would lift it into a rarer tier.
That score comes from 5 science badges — Near-Earth object, Potentially hazardous, Has a proper name, Apollo: crosses Earth's orbit and Stony asteroid — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.