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Asteroid Near-Earth Potentially hazardous

415029

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415029 (2011 UL21)

Where is it now

Distance from Sun
2.672 AU
True anomaly
213.49°
Distance from Earth
2.099 AU
As of
11 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.

Orbit of Mercury Orbit of Venus Orbit of Mars Sun Earth — 0.998 AU from the Sun Earth 415029 — 2.672 AU from the Sun 415029
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 415029 is 2.099 AU from Earth today (17.5 light-minutes).

In the sky

Right ascension
05h 03m 35s
Declination
+51° 53′ 10″
Constellation
Auriga
Distance from Earth
2.09 AU
Elongation from the Sun
115.05° — well clear of the Sun

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
2.122 AU
Eccentricity
0.6538
Inclination
34.89°
Orbital period
3.09 years
Perihelion
0.735 AU
Aphelion
3.51 AU
Longitude of ascending node
275.31°
Argument of periapsis
284.98°
Epoch · J2000
2461200.5
Orbit class · APO
Apollo
Earth MOID · 6.4 LD
0.0166 AU
Tisserand (Jupiter)
3.245

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
2,113
Data arc
34.86 years
First observed
29 October 1989
Last observed
9 September 2024
Residual RMS
0.31 ″
Solution · Otto Matic
21 October 2025

Physical properties

Rotation period
2.73 hours

Visual & observation

Absolute magnitude (H)
15.93

Discovery & classification

Discovered by
CSS
Discovery date
17 October 2011
Discovery site
Catalina

Also known as 2011 UL21

Apollo Near-Earth Object Potentially Hazardous Asteroid

Close approaches 10 on record

Flyby geometry
Ecliptic flyby of 415029 at 2089-06-25 03:48 UTC Top-down view of the ecliptic, Earth at the centre, for the 2089-06-25 03:48 UTC close approach of 415029. Catalogue miss distance 6.94 LD · 2.67 × 10⁶ km. The curve is the geocentric path from 2089-06-22 to 2089-06-28, 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 23 Jun 27 Jun 6.94 LD · 2.67 × 10⁶ km 2089-06-25 03:48 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2089-06-25 03:48 UTC close approach of 415029. Catalogue miss distance 6.94 LD · 2.67 × 10⁶ km. The curve is the geocentric path from 2089-06-22 to 2089-06-28, 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
2089-06-25 03:48:00 Earth 0.0178 AU 6.9 LD 25 km/s
2107-08-24 12:39:00 Mars 0.0977 AU 38.0 LD 24.6 km/s
2123-07-01 02:53:00 Earth 0.0993 AU 38.6 LD 27 km/s
2154-06-16 20:42:00 Earth 0.1734 AU 67.5 LD 21.9 km/s
2188-06-22 07:41:00 Earth 0.0538 AU 20.9 LD 24.1 km/s

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

Sources