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Asteroid Near-Earth

2021 TU1

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(2021 TU1)

Where is it now

Distance from Sun
1.068 AU
True anomaly
137.01°
Distance from Earth
0.461 AU
As of
20 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 2021 TU1 — 1.068 AU from the Sun 2021 TU1
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2021 TU1 is 0.461 AU from Earth today (3.8 light-minutes).

In the sky

Right ascension
19h 52m 39s
Declination
-29° 12′ 41″
Constellation
Sagittarius
Distance from Earth
0.47 AU
Elongation from the Sun
86.49° — well clear of the Sun

Favours the southern hemisphere; low or below the horizon from far north.

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
0.899 AU
Eccentricity
0.4585
Inclination
6.75°
Orbital period
311.3 days
Perihelion
0.487 AU
Aphelion
1.311 AU
Longitude of ascending node
151.2°
Argument of periapsis
74.03°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 18.2 LD
0.0466 AU
Tisserand (Jupiter)
6.522

Orbit quality

Orbit very well determined (uncertainty code 2).

Observations used
45
Data arc
446 days
First observed
3 October 2021
Last observed
23 December 2022
Residual RMS
0.55 ″
Solution · Otto Matic
24 December 2022

Visual & observation

Absolute magnitude (H)
22.54

Discovery & classification

Aten Near-Earth Object

Close approaches 278 on record

Flyby geometry
Ecliptic flyby of 2021 TU1 at 2027-07-04 01:04 UTC Top-down view of the ecliptic, Earth at the centre, for the 2027-07-04 01:04 UTC close approach of 2021 TU1. Catalogue miss distance 175.6 LD · 6.75 × 10⁷ km. The curve is the geocentric path from 2027-07-01 to 2027-07-07, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 175.6 LD · 6.75 × 10⁷ km 2027-07-04 01:04 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2027-07-04 01:04 UTC close approach of 2021 TU1. Catalogue miss distance 175.6 LD · 6.75 × 10⁷ km. The curve is the geocentric path from 2027-07-01 to 2027-07-07, with a mark at UTC midnights and an arrow for the direction of motion. The circle is the Moon’s mean orbit; the Moon is plotted at closest approach. A ray shows the Sun’s direction. The labelled distance is the full separation. The drawn radius is the part that lies in the ecliptic plane. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate.

JPL Horizons

When (UTC) Body Distance Lunar distances Relative speed
2026-09-29 23:58:00 Earth 0.3615 AU 140.7 LD 25.3 km/s
2027-06-15 06:44:00 Merc 0.097 AU 37.8 LD 15.3 km/s
2027-06-15 06:44:00 Mercury 0.097 AU 37.8 LD 15.3 km/s
2027-07-04 01:04:00 Earth 0.4512 AU 175.6 LD 14.9 km/s
2027-10-30 01:42:00 Earth 0.3374 AU 131.3 LD 10.9 km/s
2028-04-04 11:54:00 Earth 0.4928 AU 191.8 LD 19.6 km/s
2028-12-25 01:42:00 Earth 0.2119 AU 82.5 LD 20 km/s
2032-09-21 03:43:00 Earth 0.1568 AU 61.0 LD 18.7 km/s
2033-11-20 01:27:00 Earth 0.336 AU 130.7 LD 10.8 km/s
2034-03-11 22:45:00 Earth 0.4317 AU 168.0 LD 15.1 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources