2021 YB is an asteroid in the Apollo orbit class. Its orbit takes it from 0.85 AU to 1.19 AU from the Sun; one orbit takes 374.9 days. Orbit from the JPL solution of 21 December 2021.
Where is it now
- Distance from Sun
- 1.18 AU
- True anomaly
- 192.07°
- Distance from Earth
- 0.615 AU
- As of
- 3 November 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
- 20h 50m 49s
- Declination
- -07° 25′ 34″
- Constellation
- Aquarius
- Distance from Earth
- 0.62 AU
- Elongation from the Sun
- 91.29° — 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
- 1.017 AU
- Eccentricity
- 0.1647
- Inclination
- 5.22°
- Orbital period
- 374.9 days
- Perihelion
- 0.85 AU
- Aphelion
- 1.185 AU
- Longitude of ascending node
- 270.47°
- Argument of periapsis
- 267.73°
- Epoch · J2000
- 2461200.5
- Orbit class · APO
- Apollo
- Earth MOID · 0.1 LD
- 0.0003 AU
- Tisserand (Jupiter)
- 5.983
Orbit quality
Orbit poorly determined (uncertainty code 6).
- Observations used
- 27
- Data arc
- 9 days
- First observed
- 12 December 2021
- Last observed
- 21 December 2021
- Residual RMS
- 0.38 ″
- Solution · Otto Matic
- 21 December 2021
Visual & observation
- Absolute magnitude (H)
- 27.52
Discovery & classification
Listed by JPL impact monitoring; see the Sentry table for current probabilities.
Close approaches 31 on record
Top-down view of the ecliptic, Earth at the centre, for the 2027-07-10 18:19 UTC close approach of 2021 YB. Catalogue miss distance 100.4 LD · 3.86 × 10⁷ km. The curve is the geocentric path from 2027-07-07 to 2027-07-13, 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 |
|---|---|---|---|---|
| 2027-07-10 18:19:00 | Earth | 0.258 AU | 100.4 LD | 12.7 km/s |
| 2028-07-17 13:10:00 | Earth | 0.4226 AU | 164.5 LD | 17.5 km/s |
| 2056-12-04 00:09:00 | Earth | 0.4246 AU | 165.2 LD | 18 km/s |
| 2057-12-11 21:35:00 | Earth | 0.2517 AU | 97.9 LD | 12.8 km/s |
| 2058-12-19 20:01:00 | Earth | 0.0778 AU | 30.3 LD | 7.7 km/s |
| 2059-12-26 08:57:00 | Earth | 0.089 AU | 34.7 LD | 3.5 km/s |
| 2060-10-22 11:32:00 | Earth | 0.1914 AU | 74.5 LD | 4.5 km/s |
| 2061-03-17 16:56:00 | Earth | 0.1677 AU | 65.2 LD | 4.9 km/s |
| 2061-09-13 13:11:00 | Earth | 0.2048 AU | 79.7 LD | 4.6 km/s |
| 2062-05-14 17:11:00 | Earth | 0.1332 AU | 51.8 LD | 4.1 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