About Atira
Atira is a rare neo. It swings within 0.502 AU of the Sun at perihelion.
Its orbit genuinely intersects Earth's track around the Sun. The two paths cross; only the timing keeps them apart.
Rare neo 47 EP
Atira
Position computed live · sbdb
Loading sky survey…
Live ephemeris
This object moves — fetching its current position…
Score breakdown
· 4 badgesRare 50 pts → Epic
- Atira: orbits entirely inside Earth's +26
- Crosses Earth's orbit +8
- Has a proper name +8
- Near-Earth object +5
Total score 47
3 more points to reach Epic.
Badges
- Near-Earth object · +5
- Crosses Earth's orbit · +8
- Has a proper name · +8
- Atira: orbits entirely inside Earth's · +26
Trivia
What makes it special
- It crosses our path. Its orbit genuinely intersects Earth's track around the Sun. The two paths cross; only the timing keeps them apart.
What it actually is
- Its orbit family. An Atira: its entire orbit lies inside Earth's. Only a couple of dozen are known, because they are never in a dark sky when we are.
- Closest approach. At its nearest it comes within 0.5 AU of the Sun — inside the orbit of Venus.
- One lap. A single orbit around the Sun takes it about 233 days.
- How far it roams. Its orbit swings between 0.5 and 0.98 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 1.12 m/s. A determined jump would launch you off it and into your own orbit around the Sun.
By the numbers
- Estimated size. Nobody has measured its size directly. Assuming it reflects light like a typical asteroid, its brightness implies something roughly 1.9 km across.
Properties
- aphelion au
- 0.98
- designation
- 163693
- eccentricity
- 0.3222
- full name
- 163693 Atira (2003 CP20)
- h mag
- 16.41
- inclination
- 25.62
- mean motion deg day
- 1.545
- moid au
- 0.207
- name
- Atira
- named
- yes
- orbit class
- IEO
- perihelion au
- 0.502
- rotation period h
- 3.398
- semi major au
- 0.741
How to see it
Like any astronomical target, Atira 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 Atira is a rare neo
Atira scores 47 points on Spacedle's rarity scale, which places it in the rare tier. Another 3 points would lift it into a rarer tier.
That score comes from 4 science badges — Near-Earth object, Crosses Earth's orbit, Has a proper name and Atira: orbits entirely inside Earth's — 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.