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Asteroid Near-Earth Potentially hazardous

523950

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523950 (1998 SZ27)

Where is it now

Distance from Sun
0.886 AU
True anomaly
241.63°
Distance from Earth
1.107 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 523950 — 0.886 AU from the Sun 523950
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 523950 is 1.107 AU from Earth today (9.2 light-minutes).

In the sky

Right ascension
10h 25m 41s
Declination
-08° 53′ 13″
Constellation
Sextans
Distance from Earth
1.1 AU
Elongation from the Sun
49.08° — near the Sun — look low at dusk or dawn

Visible from both hemispheres.

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
0.905 AU
Eccentricity
0.5067
Inclination
23.64°
Orbital period
314.5 days
Perihelion
0.446 AU
Aphelion
1.364 AU
Longitude of ascending node
166.67°
Argument of periapsis
47.73°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 2.8 LD
0.0072 AU
Tisserand (Jupiter)
6.408

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
150
Data arc
25.12 years
First observed
21 September 1998
Last observed
4 November 2023
Residual RMS
0.45 ″
Solution · Otto Matic
5 May 2026

Visual & observation

Absolute magnitude (H)
20.17

Discovery & classification

Discovered by
LINEAR
Discovery date
21 September 1998
Discovery site
Socorro

Also known as 1998 SZ27

Aten Near-Earth Object Potentially Hazardous Asteroid

Close approaches 64 on record

Flyby geometry
Ecliptic flyby of 523950 at 2029-09-11 02:43 UTC Top-down view of the ecliptic, Earth at the centre, for the 2029-09-11 02:43 UTC close approach of 523950. Catalogue miss distance 35.6 LD · 1.37 × 10⁷ km. The curve is the geocentric path from 2029-09-08 to 2029-09-14, 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 north of the ecliptic. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate. Sun 35.6 LD · 1.37 × 10⁷ km 2029-09-11 02:43 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2029-09-11 02:43 UTC close approach of 523950. Catalogue miss distance 35.6 LD · 1.37 × 10⁷ km. The curve is the geocentric path from 2029-09-08 to 2029-09-14, 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 north 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
2026-12-03 17:09:00 Merc 0.0906 AU 35.3 LD 26.4 km/s
2026-12-03 17:09:00 Mercury 0.0906 AU 35.3 LD 26.4 km/s
2029-09-11 02:43:00 Earth 0.0914 AU 35.6 LD 21.1 km/s
2043-04-17 15:38:00 Mercury 0.0999 AU 38.9 LD 34.3 km/s
2043-04-17 15:38:00 Merc 0.0999 AU 38.9 LD 34.3 km/s
2048-09-08 04:02:00 Earth 0.1964 AU 76.4 LD 14.9 km/s
2049-04-26 12:53:00 Mercury 0.0697 AU 27.1 LD 29.1 km/s
2049-04-26 12:53:00 Merc 0.0697 AU 27.1 LD 29.1 km/s
2054-09-08 04:45:00 Earth 0.0416 AU 16.2 LD 17.8 km/s
2060-09-11 07:55:00 Earth 0.1017 AU 39.6 LD 21.4 km/s

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

Sources