A/2021 X2
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	8 Jul 2022	22.2	2.998 AU	3.514 AU	03h36m	+11°23'	52.1°	15.5°	250°
Nearest approach	4 Oct 2022	21.1	3.122 AU	2.261 AU	02h25m	-21°39'	143.5°	11.0°	312°
Today	1 Oct 2026	27.6	12.416 AU	12.642 AU	17h06m	-51°28'	74.7°	4.5°	105°

The interactive orbit chart above shows the comet'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.)

Light curve

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations from COBS. The displayed light curve is calculated under the assumption that the object remains inactive. (H=16.20; G=.15).

Charts

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

The following chart shows the short-term path of the comet in a field of view that is optimized for (~10x50) binoculars and finderscopes.

Orbital elements

The orbital elements of A/2021 X2 are:

    e (Eccentricity)                : 1.0018490
    q (Perihelion distance)         : 2.9979430
    i (Inclination)                 : 137.13680
    Ω (Longitude of ascending node) : 228.87270
    ω (Argument of perihelion)      : 193.42310
    L (Longitude of perihelion)     : 218.95019
    B (Latitude of perihelion)      : -9.08580
    T (Time of perihelion passage)  : 2459769.21390

    Epoch                           : 2026 May 29
    Reference                       : MPC194178

    Classification(s):              : Nearly isotropic; New (a > 10000 AU)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-09-30 00:00 UT   17 06 23.0   -51 32 47    12.609   12.406   76.0    4.5   104   27.6 
2026-10-01 00:00 UT   17 06 29.7   -51 30 14    12.630   12.412   75.2    4.5   104   27.6 
2026-10-01 13:57 UT   17 06 33.8   -51 28 46    12.642   12.416   74.7    4.5   105   27.6 
2026-10-02 00:00 UT   17 06 36.9   -51 27 42    12.650   12.418   74.4    4.5   105   27.6 
2026-10-03 00:00 UT   17 06 44.5   -51 25 12    12.671   12.424   73.5    4.4   105   27.6 
2026-10-04 00:00 UT   17 06 52.5   -51 22 44    12.691   12.430   72.7    4.4   106   27.6 
2026-10-05 00:00 UT   17 07 01.0   -51 20 17    12.711   12.436   71.8    4.4   106   27.6 
2026-10-06 00:00 UT   17 07 09.9   -51 17 52    12.732   12.442   71.0    4.4   107   27.6 
2026-10-07 00:00 UT   17 07 19.2   -51 15 28    12.752   12.448   70.1    4.3   107   27.6 
2026-10-08 00:00 UT   17 07 29.0   -51 13 07    12.772   12.454   69.3    4.3   108   27.6 
2026-10-09 00:00 UT   17 07 39.1   -51 10 47    12.792   12.460   68.5    4.3   108   27.6 
2026-10-10 00:00 UT   17 07 49.7   -51 08 29    12.812   12.466   67.6    4.2   109   27.6 
2026-10-11 00:00 UT   17 08 00.6   -51 06 12    12.832   12.472   66.8    4.2   109   27.6 

    Terminology:
            
    delta:  distance between comet and earth in AU
    radius: distance between comet 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-comet)    
    phase:  phase angle in degrees (angle sun-comet-earth)        
    AU:     Astronomical Unit (mean distance between earth and sun: 149597870.7 km      
    

Orbital elements usually provided by the MPC (Minor Planet Center).
Observations contributed by observers worldwide, via COBS (Comet Observation Database) or 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.