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Trans-Neptunian object

Uni

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55637 Uni (2002 UX25)

Where is it now

Distance from Sun
39.447 AU
True anomaly
296.34°
Distance from Earth
38.595 AU
As of
19 October 2026

Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.

Sun Earth — 0.996 AU from the Sun Earth Uni — 39.447 AU from the Sun Uni
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Uni is 38.595 AU from Earth today (5.3 light-hours).

In the sky

Right ascension
03h 45m 47s
Declination
+09° 05′ 36″
Constellation
Taurus
Distance from Earth
38.59 AU
Elongation from the Sun
148.64° — well clear of the Sun

Visible from both hemispheres.

From your location

See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.

How do I find my coordinates?

Google Maps on a computer

  1. Right-click the spot where you'll be observing.
  2. The first line of the menu is the coordinates, e.g. 51.50722, -0.12758 — click it and they're copied.
  3. Paste them above.

Google Maps on a phone

  1. Press and hold the spot to drop a pin.
  2. The coordinates appear in the search bar (or on the pin's card) — tap to copy, then paste above.

A full Google Maps link works too, but the short maps.app.goo.gl share links don't carry coordinates — copy the numbers instead. We round to about a kilometre; that's all the sky calculation needs.

Know your what3words address? Paste it, e.g. ///filled.count.soap. This is optional — the three words are sent to what3words to convert them, and we don't store the address or the result.

Your location stays in your browser and is sent only for this calculation. Using a what3words address is optional; if you do, the three words go to what3words to be converted and we don't record them. Set a location first, then you can save an email alert for this object. See our privacy policy.

Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.

Orbital elements

Semi-major axis
42.925 AU
Eccentricity
0.1462
Inclination
19.42°
Orbital period
281.2 years
Perihelion
36.647 AU
Aphelion
49.202 AU
Longitude of ascending node
204.62°
Argument of periapsis
276.1°
Epoch · J2000
2461200.5
Orbit class · TNO
Trans-Neptunian object
Earth MOID · 13,901.1 LD
35.7197 AU
Tisserand (Jupiter)
5.48

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
1,641
Data arc
34.41 years
First observed
12 October 1991
Last observed
9 March 2026
Residual RMS
0.52 ″
Solution · Otto Matic
6 June 2026

Physical properties

Rotation period
14.38 hours

Visual & observation

Absolute magnitude (H)
3.83

Discovery & classification

Discovered by
Spacewatch
Discovery date
30 October 2002
Discovery site
Kitt Peak

Uni is the Etruscan goddess of love and fertility. She is one of the three main gods of the pantheon. The satellite (55637) Uni I is named for Uni's husband, the sky god Tinia.

Also known as 55637 · 2002 UX25

Named TNO

Sources