About (21788) 1999 SZ5
(21788) 1999 SZ5 is a trash asteroid. It swings within 1.651 AU of the Sun at perihelion.
A Mars-crosser: its orbit reaches in far enough to cut clean across the path of Mars.
Trash asteroid 6 EP
(21788) 1999 SZ5
Position computed live · sbdb
Loading sky survey…
Live ephemeris
This object moves — fetching its current position…
Score breakdown
· 3 badgesTrash 15 pts → Common
- Mars-crosser +5
- Asteroid +1
- Catalogue designation only +0
Total score 6
9 more points to reach Common.
Badges
- Asteroid · +1
- Catalogue designation only
- Mars-crosser · +5
Trivia
What it actually is
- Its orbit family. A Mars-crosser: its orbit reaches in far enough to cut clean across the path of Mars.
- Closest approach. At its nearest it comes within 1.65 AU of the Sun — inside the orbit of Jupiter.
- One lap. A single orbit around the Sun takes it about 3.8 years.
- How far it roams. Its orbit swings between 1.65 and 3.21 AU from the Sun.
Sense of scale
- Sense of scale. In everyday terms it is roughly 0.4× the height of Mount Everest.
By the numbers
- Size. Roughly 3.3 km across.
What's in a name
- Designation. Known only by its catalogue designation — no name yet.
Properties
- albedo
- 0.37
- aphelion au
- 3.21
- designation
- 21788
- diameter km
- 3.324
- eccentricity
- 0.3202
- full name
- 21788 (1999 SZ5)
- h mag
- 14.23
- inclination
- 22.6
- mean motion deg day
- 0.2604
- moid au
- 0.746
- name
- (21788) 1999 SZ5
- number only
- yes
- orbit class
- MCA
- perihelion au
- 1.651
- semi major au
- 2.429
How to see it
Like any astronomical target, (21788) 1999 SZ5 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 (21788) 1999 SZ5 is a trash asteroid
(21788) 1999 SZ5 scores 6 points on Spacedle's rarity scale, which places it in the trash tier. Another 9 points would lift it into a rarer tier.
That score comes from 3 science badges — Asteroid, Catalogue designation only and Mars-crosser — 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.