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Trans-Neptunian object

20161

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20161 (1996 TR66)

20161 is a trans-Neptunian object in the Trans-Neptunian object orbit class. Its orbit takes it from 28.95 AU to 66.85 AU from the Sun; one orbit takes 331.5 years. Discovered 8 October 1996 by Jewitt, D. C., Trujillo, C. A., Luu, J. X., Chen, J.. Orbit from the JPL solution of 13 April 2021.

Where is it now

Distance from Sun
47.105 AU
True anomaly
111.08°
Distance from Earth
46.147 AU
As of
25 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 — 0.994 AU from the Sun Earth 20161 — 47.105 AU from the Sun 20161
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 20161 is 46.147 AU from Earth today (6.4 light-hours).

In the sky

Right ascension
02h 29m 40s
Declination
+26° 25′ 18″
Constellation
Aries
Distance from Earth
46.15 AU
Elongation from the Sun
164.87° — near opposition — up most of the night

Favours the northern hemisphere; low or below the horizon from far south.

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
47.9 AU
Eccentricity
0.3956
Inclination
12.43°
Orbital period
331.5 years
Perihelion
28.948 AU
Aphelion
66.851 AU
Longitude of ascending node
343.15°
Argument of periapsis
309.68°
Epoch · J2000
2461200.5
Orbit class · TNO
Trans-Neptunian object
Earth MOID · 10,875.9 LD
27.9462 AU
Tisserand (Jupiter)
5.551

Orbit quality

Orbit reasonably well determined (uncertainty code 4).

Observations used
32
Data arc
19.84 years
First observed
8 October 1996
Last observed
12 August 2016
Residual RMS
0.74 ″
Solution · Otto Matic
13 April 2021

Visual & observation

Absolute magnitude (H)
7.43

Discovery & classification

Discovered by
Jewitt, D. C., Trujillo, C. A., Luu, J. X., Chen, J.
Discovery date
8 October 1996
Discovery site
Mauna Kea

Also known as 1996 TR66

TNO

Sources