2021 AB
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	13 Sep 2026	31.4	4.034 AU	3.239 AU	20h36m	-17°51'	137.0°	9.8°

The interactive orbit chart above shows the body's path through the solar system and its position at the given date. Green and blue lines are shown perpendicular to the ecliptic plane: Green if the path is above the ecliptic plane, blue if it is below. (Left-click and drag to rotate the view; Right-click and drag to move the view; Use scroll wheel to zoom in our out.)

The orbital elements of 2021 AB are:

            e (Eccentricity)                : 0.6492083
            a (Semimajor axis)              : 2.5129188
            i (Inclination)                 : 1.42582
            Ω (Longitude of ascending node) : 293.09222
            ω (Argument of perihelion)      : 213.44991
            M (Mean anomaly)                : 121.68256
            Epoch                           : 2026 Jun 09

            L (Longitude of perihelion)     : 326.53397
            B (Latitude of perihelion)      : -0.78587
            P (Orbital period in years)     : 3.98            
        

The light curve chart below shows the estimated development of the minor planet's magnitude.

The all-sky chart below shows the path of the minor planet over the same period as the light curve. The current position is marked yellow.

The following chart shows the path of the minor planet in the next few days. The field of view is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-09-13 00:00 UT   20 36 27.1   -17 51 30     3.239    4.034  137.0    9.8    76   31.4 
2026-09-13 00:49 UT   20 36 26.0   -17 51 34     3.240    4.035  137.0    9.8    76   31.4 
2026-09-14 00:00 UT   20 35 57.4   -17 53 21     3.252    4.036  135.9   10.0    76   31.4 
2026-09-15 00:00 UT   20 35 28.9   -17 55 08     3.265    4.038  134.8   10.2    76   31.4 
2026-09-16 00:00 UT   20 35 01.4   -17 56 51     3.278    4.039  133.8   10.4    76   31.5 
2026-09-17 00:00 UT   20 34 35.0   -17 58 29     3.291    4.041  132.7   10.5    76   31.5 
2026-09-18 00:00 UT   20 34 09.8   -18 00 03     3.305    4.042  131.6   10.7    76   31.5 
2026-09-19 00:00 UT   20 33 45.7   -18 01 34     3.318    4.044  130.5   10.9    76   31.5 
2026-09-20 00:00 UT   20 33 22.7   -18 02 60     3.332    4.045  129.5   11.1    76   31.5 
2026-09-21 00:00 UT   20 33 00.8   -18 04 22     3.346    4.047  128.4   11.2    76   31.5 
2026-09-22 00:00 UT   20 32 40.0   -18 05 39     3.360    4.048  127.3   11.4    76   31.6 
2026-09-23 00:00 UT   20 32 20.4   -18 06 53     3.374    4.050  126.3   11.5    76   31.6 
2026-09-24 00:00 UT   20 32 01.9   -18 08 03     3.389    4.051  125.2   11.7    76   31.6 
2026-09-25 00:00 UT   20 31 44.5   -18 09 08     3.403    4.053  124.2   11.8    76   31.6 
2026-09-26 00:00 UT   20 31 28.3   -18 10 09     3.418    4.054  123.1   12.0    76   31.6 
2026-09-27 00:00 UT   20 31 13.2   -18 11 07     3.433    4.055  122.1   12.1    76   31.6 
2026-09-28 00:00 UT   20 30 59.2   -18 12 00     3.448    4.057  121.0   12.2    76   31.7 
2026-09-29 00:00 UT   20 30 46.3   -18 12 50     3.463    4.058  120.0   12.3    76   31.7 
2026-09-30 00:00 UT   20 30 34.6   -18 13 35     3.479    4.060  119.0   12.5    76   31.7 
2026-10-01 00:00 UT   20 30 23.9   -18 14 16     3.494    4.061  117.9   12.6    76   31.7 
2026-10-02 00:00 UT   20 30 14.4   -18 14 54     3.510    4.062  116.9   12.7    76   31.7 
2026-10-03 00:00 UT   20 30 06.0   -18 15 27     3.526    4.064  115.9   12.8    76   31.7 
2026-10-04 00:00 UT   20 29 58.7   -18 15 57     3.541    4.065  114.9   12.9    76   31.7 
2026-10-05 00:00 UT   20 29 52.5   -18 16 23     3.557    4.066  113.9   13.0    76   31.8 
2026-10-06 00:00 UT   20 29 47.5   -18 16 45     3.573    4.068  112.9   13.1    76   31.8 
2026-10-07 00:00 UT   20 29 43.5   -18 17 03     3.589    4.069  111.9   13.2    76   31.8 
2026-10-08 00:00 UT   20 29 40.6   -18 17 17     3.606    4.070  110.9   13.3    76   31.8 
2026-10-09 00:00 UT   20 29 38.8   -18 17 27     3.622    4.072  109.9   13.3    76   31.8 
2026-10-10 00:00 UT   20 29 38.1   -18 17 34     3.638    4.073  108.9   13.4    76   31.8 
2026-10-11 00:00 UT   20 29 38.5   -18 17 37     3.655    4.074  107.9   13.5    76   31.8 
2026-10-12 00:00 UT   20 29 39.9   -18 17 36     3.672    4.076  106.9   13.6    76   31.8 
2026-10-13 00:00 UT   20 29 42.4   -18 17 31     3.688    4.077  105.9   13.6    76   31.9 

    Terminology:
            
    delta:  distance between minor planet and earth in AU
    radius: distance between minor planet and sun in AU
    magn:   magnitude (brightness) estimate    
    ra:     right ascension in hours (24h = 360deg)
    dec:    declination in degrees
    elong:  elongation in degrees (angle sun-earth-minor planet)    
    phase:  phase angle in degrees (angle sun-minor planet-earth)        
    AU:     Astronomical Unit (mean distance between earth and sun: 149597870.7 km
    

Orbital elements provided by the MPC (Minor Planet Center).
Calculations by a modified version of AAPlus, a C# implementation of the AA+ project by PJ Naughter from the algorithms presented in the book "Astronomical Algorithms" by Jean Meeus.
NGC2000 dso catalog and star labels from VizieR as provided by the Strasbourg astronomical Data Center.
Tycho2 catalog from the ESO archive.