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Asteroid Near-Earth

2009 SZ99

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(2009 SZ99)

Where is it now

Distance from Sun
0.7 AU
True anomaly
301.04°
Distance from Earth
0.731 AU
As of
16 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 — 0.997 AU from the Sun Earth 2009 SZ99 — 0.7 AU from the Sun 2009 SZ99
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2009 SZ99 is 0.731 AU from Earth today (6.1 light-minutes).

In the sky

Right ascension
11h 33m 20s
Declination
+24° 49′ 54″
Constellation
Leo
Distance from Earth
0.74 AU
Elongation from the Sun
44.36° — 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
0.815 AU
Eccentricity
0.2145
Inclination
21.33°
Orbital period
268.6 days
Perihelion
0.64 AU
Aphelion
0.99 AU
Longitude of ascending node
338.02°
Argument of periapsis
147.56°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 22.5 LD
0.0577 AU
Tisserand (Jupiter)
7.106

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
66
Data arc
16.72 years
First observed
22 September 2009
Last observed
11 June 2026
Residual RMS
0.54 ″
Solution · Otto Matic
11 June 2026

Visual & observation

Absolute magnitude (H)
19.32

Discovery & classification

Aten Near-Earth Object

Close approaches 56 on record

Flyby geometry
Ecliptic flyby of 2009 SZ99 at 2034-09-01 20:15 UTC Top-down view of the ecliptic, Earth at the centre, for the 2034-09-01 20:15 UTC close approach of 2009 SZ99. Catalogue miss distance 61.4 LD · 2.36 × 10⁷ km. The curve is the geocentric path from 2034-08-29 to 2034-09-04, 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 61.4 LD · 2.36 × 10⁷ km 2034-09-01 20:15 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2034-09-01 20:15 UTC close approach of 2009 SZ99. Catalogue miss distance 61.4 LD · 2.36 × 10⁷ km. The curve is the geocentric path from 2034-08-29 to 2034-09-04, 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
2027-08-24 10:04:00 Venus 0.0811 AU 31.6 LD 16.1 km/s
2031-04-25 10:40:00 Venus 0.0805 AU 31.3 LD 15.4 km/s
2034-09-01 20:15:00 Earth 0.1578 AU 61.4 LD 10.9 km/s
2034-12-24 10:31:00 Venus 0.146 AU 56.8 LD 15.7 km/s
2048-08-28 08:26:00 Earth 0.0587 AU 22.8 LD 11.3 km/s
2057-10-20 10:29:00 Venus 0.1206 AU 46.9 LD 17 km/s
2059-09-02 09:19:00 Earth 0.1744 AU 67.9 LD 11 km/s
2061-06-21 18:36:00 Venus 0.0686 AU 26.7 LD 15.7 km/s
2062-08-23 03:38:00 Earth 0.1829 AU 71.2 LD 13.8 km/s
2065-02-20 13:06:00 Venus 0.1018 AU 39.6 LD 15.4 km/s

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

Sources