About 2009 UD
2009 UD is a rare neo. It swings within 0.913 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 39 EP
2009 UD
Position computed live · sbdb
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Live ephemeris
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Score breakdown
· 5 badgesRare 50 pts → Epic
- Spinning past the rubble-pile limit +22
- Crosses Earth's orbit +8
- Near-Earth object +5
- Apollo: crosses Earth's orbit +4
- Catalogue designation only +0
Total score 39
11 more points to reach Epic.
Badges
- Near-Earth object · +5
- Crosses Earth's orbit · +8
- Catalogue designation only
- Apollo: crosses Earth's orbit · +4
- Spinning past the rubble-pile limit · +22
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 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 0.91 AU of the Sun — inside the orbit of Earth.
- One lap. A single orbit around the Sun takes it about 1.1 years.
- How far it roams. Its orbit swings between 0.91 and 1.17 AU from the Sun.
Sense of scale
- Sense of scale. In everyday terms it is about 0.1 football pitches across.
Standing on it
- Don't jump. Escape velocity here is only around 0.01 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 13 metres across.
Properties
- aphelion au
- 1.17
- designation
- 2009 UD
- eccentricity
- 0.1215
- full name
- (2009 UD)
- h mag
- 27.2
- inclination
- 4.41
- mean motion deg day
- 0.9302
- moid au
- 0.0056
- name
- 2009 UD
- number only
- yes
- orbit class
- APO
- perihelion au
- 0.913
- rotation period h
- 0.0232
- semi major au
- 1.039
How to see it
Like any astronomical target, 2009 UD 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 2009 UD is a rare neo
2009 UD scores 39 points on Spacedle's rarity scale, which places it in the rare tier. Another 11 points would lift it into a rarer tier.
That score comes from 5 science badges — Near-Earth object, Crosses Earth's orbit, Catalogue designation only, Apollo: crosses Earth's orbit and Spinning past the rubble-pile limit — 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.