2021 SD3 is an asteroid in the Aten orbit class. Its orbit takes it from 0.81 AU to 1.14 AU from the Sun; one orbit takes 352.7 days. Orbit from the JPL solution of 24 October 2021.
Where is it now
- Distance from Sun
- 1.115 AU
- True anomaly
- 206.83°
- Distance from Earth
- 0.717 AU
- As of
- 24 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.
In the sky
- Right ascension
- 08h 48m 52s
- Declination
- +08° 35′ 19″
- Constellation
- Cancer
- Distance from Earth
- 0.72 AU
- Elongation from the Sun
- 79.53° — well clear of the Sun
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.
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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
- 0.977 AU
- Eccentricity
- 0.1658
- Inclination
- 6.29°
- Orbital period
- 352.7 days
- Perihelion
- 0.815 AU
- Aphelion
- 1.139 AU
- Longitude of ascending node
- 185.83°
- Argument of periapsis
- 37.67°
- Epoch · J2000
- 2461200.5
- Orbit class · ATE
- Aten
- Earth MOID · 19.7 LD
- 0.0505 AU
- Tisserand (Jupiter)
- 6.176
Orbit quality
Orbit reasonably well determined (uncertainty code 5).
- Observations used
- 23
- Data arc
- 9 days
- First observed
- 30 September 2021
- Last observed
- 9 October 2021
- Residual RMS
- 0.5 ″
- Solution · Otto Matic
- 24 October 2021
Visual & observation
- Absolute magnitude (H)
- 25.12
Discovery & classification
Close approaches 111 on record
Top-down view of the ecliptic, Earth at the centre, for the 2047-09-13 17:49 UTC close approach of 2021 SD3. Catalogue miss distance 158.4 LD · 6.09 × 10⁷ km. The curve is the geocentric path from 2047-09-10 to 2047-09-16, 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. The path is a geocentric ecliptic ephemeris from JPL Horizons. The inset is a heliocentric view and is approximate.
| When (UTC) | Body | Distance | Lunar distances | Relative speed |
|---|---|---|---|---|
| 2047-09-13 17:49:00 | Earth | 0.4069 AU | 158.4 LD | 17.5 km/s |
| 2048-09-05 18:03:00 | Earth | 0.203 AU | 79.0 LD | 11.3 km/s |
| 2049-09-05 20:09:00 | Earth | 0.0512 AU | 19.9 LD | 5.7 km/s |
| 2050-06-18 10:37:00 | Earth | 0.1982 AU | 77.1 LD | 5.2 km/s |
| 2050-10-20 01:57:00 | Earth | 0.1502 AU | 58.4 LD | 5.1 km/s |
| 2051-04-29 17:34:00 | Earth | 0.2 AU | 77.8 LD | 6.7 km/s |
| 2051-12-14 06:17:00 | Earth | 0.1617 AU | 62.9 LD | 4.2 km/s |
| 2052-03-10 19:01:00 | Earth | 0.1397 AU | 54.4 LD | 5.5 km/s |
| 2053-01-26 06:05:00 | Earth | 0.1169 AU | 45.5 LD | 7.7 km/s |
| 2054-01-14 09:29:00 | Earth | 0.302 AU | 117.5 LD | 14.1 km/s |
Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.
Sources
- visual properties: JPL SBDB (lookup)
- orbital elements: JPL SBDB