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Asteroid Near-Earth

2021 AZ4

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(2021 AZ4)

Where is it now

Distance from Sun
1.446 AU
True anomaly
174.36°
Distance from Earth
1.862 AU
As of
22 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 — 0.995 AU from the Sun Earth 2021 AZ4 — 1.446 AU from the Sun 2021 AZ4
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2021 AZ4 is 1.862 AU from Earth today (15.5 light-minutes).

In the sky

Right ascension
10h 59m 44s
Declination
+15° 49′ 21″
Constellation
Leo
Distance from Earth
1.85 AU
Elongation from the Sun
50.74° — near the Sun — look low at dusk or dawn

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
0.963 AU
Eccentricity
0.5082
Inclination
44.52°
Orbital period
345.4 days
Perihelion
0.474 AU
Aphelion
1.453 AU
Longitude of ascending node
115.89°
Argument of periapsis
201.28°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 117.4 LD
0.3017 AU
Tisserand (Jupiter)
5.929

Orbit quality

Orbit very well determined (uncertainty code 1).

Observations used
76
Data arc
3 years
First observed
10 January 2019
Last observed
8 January 2022
Residual RMS
0.51 ″
Solution · Otto Matic
9 January 2022

Visual & observation

Absolute magnitude (H)
21.45

Discovery & classification

Aten Near-Earth Object

Close approaches 122 on record

Flyby geometry
Ecliptic flyby of 2021 AZ4 at 2036-01-08 18:44 UTC Top-down view of the ecliptic, Earth at the centre, for the 2036-01-08 18:44 UTC close approach of 2021 AZ4. Catalogue miss distance 164.9 LD · 6.34 × 10⁷ km. The curve is the geocentric path from 2036-01-05 to 2036-01-11, 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. At closest approach the object is south of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 164.9 LD · 6.34 × 10⁷ km 2036-01-08 18:44 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2036-01-08 18:44 UTC close approach of 2021 AZ4. Catalogue miss distance 164.9 LD · 6.34 × 10⁷ km. The curve is the geocentric path from 2036-01-05 to 2036-01-11, 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. At closest approach the object is south of the ecliptic. 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
2030-02-23 11:25:00 Mercury 0.0709 AU 27.6 LD 35.7 km/s
2030-02-23 11:25:00 Merc 0.0709 AU 27.6 LD 35.7 km/s
2036-01-08 18:44:00 Earth 0.4238 AU 164.9 LD 29.3 km/s
2037-01-05 05:56:00 Earth 0.305 AU 118.7 LD 24 km/s
2038-01-08 23:31:00 Earth 0.3451 AU 134.3 LD 22 km/s
2039-01-16 01:23:00 Earth 0.45 AU 175.1 LD 21.5 km/s
2042-06-09 21:20:00 Mercury 0.0612 AU 23.8 LD 36.3 km/s
2042-06-09 21:20:00 Merc 0.0612 AU 23.8 LD 36.3 km/s
2054-01-05 20:47:00 Earth 0.3336 AU 129.8 LD 25.8 km/s
2055-01-07 07:19:00 Earth 0.3138 AU 122.1 LD 22.5 km/s

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

Sources