This object moves — fetching its current position…
Score breakdown
· 4 badges
25 pts · Uncommon
Uncommon34 pts → Rare
Potentially hazardous+12
Aten: mostly inside Earth's orbit+8
Near-Earth object+5
Catalogue designation only+0
Total score25
9 more points to reach Rare.
Badges
🌠Near-Earth object· +5
⚠️Potentially hazardous· +12
🔢Catalogue designation only
⚱️Aten: mostly inside Earth's orbit· +8
✨ 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 841 megatons — about 16.8 times the largest bomb ever detonated.
What it actually is
🛸Its orbit family. An Aten-class object, spending most of its time inside Earth's orbit and crossing ours from the sunward side — which makes this family wretchedly hard to spot against the daylight.
🌞Closest approach. At its nearest it comes within 0.3 AU of the Sun — inside the orbit of Mercury.
🔁One lap. A single orbit around the Sun takes it about 332 days.
🥏How far it roams. Its orbit swings between 0.3 and 1.58 AU from the Sun.
Sense of scale
🧱Sense of scale. In everyday terms it is about 2.2 football pitches across.
Standing on it
🔥Sunlight there. At closest approach the Sun beats down about 11.1 times harder than it ever does on Earth.
Properties
aphelion au
1.58
designation
403775
eccentricity
0.68
full name
403775 (2011 HS4)
h mag
20.9
inclination
5.46
mean motion deg day
1.084
moid au
0.0059
name
(403775) 2011 HS4
number only
yes
orbit class
ATE
perihelion au
0.3
pha
yes
semi major au
0.9384
About (403775) 2011 HS4
(403775) 2011 HS4 is an uncommon neo. It swings within 0.3 AU of the Sun at perihelion.
An Aten-class object, spending most of its time inside Earth's orbit and crossing ours from the sunward side — which makes this family wretchedly hard to spot against the daylight.
How to see it
Like any astronomical target, (403775) 2011 HS4 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 (403775) 2011 HS4 is an uncommon neo
(403775) 2011 HS4 scores 25 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 9 points would lift it into a rarer tier.
That score comes from 4 science badges — Near-Earth object, Potentially hazardous, Catalogue designation only and Aten: mostly inside Earth's orbit — 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.