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Asteroid Near-Earth

2017 SD20

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(2017 SD20)

Where is it now

Distance from Sun
0.941 AU
True anomaly
231.74°
Distance from Earth
1.114 AU
As of
19 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 2017 SD20 — 0.941 AU from the Sun 2017 SD20
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. 2017 SD20 is 1.114 AU from Earth today (9.3 light-minutes).

In the sky

Right ascension
10h 18m 12s
Declination
+04° 42′ 04″
Constellation
Sextans
Distance from Earth
1.11 AU
Elongation from the Sun
52.44° — 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
0.852 AU
Eccentricity
0.453
Inclination
6.48°
Orbital period
287.1 days
Perihelion
0.466 AU
Aphelion
1.238 AU
Longitude of ascending node
187.32°
Argument of periapsis
37.32°
Epoch · J2000
2461200.5
Orbit class · ATE
Aten
Earth MOID · 5.1 LD
0.013 AU
Tisserand (Jupiter)
6.826

Orbit quality

Orbit poorly determined (uncertainty code 6).

Observations used
39
Data arc
9 days
First observed
27 September 2017
Last observed
6 October 2017
Residual RMS
0.65 ″
Solution · Otto Matic
9 December 2025

Visual & observation

Absolute magnitude (H)
25.97

Discovery & classification

Aten Near-Earth Object

Close approaches 113 on record

Flyby geometry
Ecliptic flyby of 2017 SD20 at 2028-09-24 03:17 UTC Top-down view of the ecliptic, Earth at the centre, for the 2028-09-24 03:17 UTC close approach of 2017 SD20. Catalogue miss distance 15.6 LD · 5.98 × 10⁶ km. The curve is the geocentric path from 2028-09-21 to 2028-09-27, 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 22 Sep 27 Sep 15.6 LD · 5.98 × 10⁶ km 2028-09-24 03:17 UTC Earth Moon Heliocentric, approximate

Top-down view of the ecliptic, Earth at the centre, for the 2028-09-24 03:17 UTC close approach of 2017 SD20. Catalogue miss distance 15.6 LD · 5.98 × 10⁶ km. The curve is the geocentric path from 2028-09-21 to 2028-09-27, 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
2028-09-24 03:17:00 Earth 0.04 AU 15.6 LD 14.5 km/s
2031-01-02 15:03:00 Venus 0.0964 AU 37.5 LD 16.4 km/s
2035-08-17 00:09:00 Merc 0.0481 AU 18.7 LD 15.8 km/s
2035-08-17 00:09:00 Mercury 0.0481 AU 18.7 LD 15.8 km/s
2036-12-10 08:20:00 Earth 0.1963 AU 76.4 LD 9.8 km/s
2038-09-03 23:45:00 Venus 0.1084 AU 42.2 LD 14.7 km/s
2039-09-26 21:39:00 Earth 0.1264 AU 49.2 LD 17.2 km/s
2044-04-09 06:01:00 Merc 0.0935 AU 36.4 LD 24.1 km/s
2044-04-09 06:01:00 Mercury 0.0935 AU 36.4 LD 24.1 km/s
2045-03-01 17:49:00 Venus 0.1412 AU 54.9 LD 21.4 km/s

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

Sources