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	17 Sep 2026	27.5	12.331 AU	12.348 AU	17h05m	-52°06'	86.7°	4.7°	98°

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
2026-09-16 00:00 UT   17 05 39.0   -52 11 11    12.315   12.321   88.0    4.7    97   27.5 
2026-09-17 00:00 UT   17 05 38.9   -52 08 17    12.336   12.328   87.1    4.7    98   27.5 
2026-09-17 13:16 UT   17 05 39.0   -52 06 42    12.348   12.331   86.7    4.7    98   27.5 
2026-09-18 00:00 UT   17 05 39.3   -52 05 25    12.357   12.334   86.3    4.7    98   27.5 
2026-09-19 00:00 UT   17 05 40.2   -52 02 34    12.378   12.340   85.4    4.7    99   27.5 
2026-09-20 00:00 UT   17 05 41.6   -51 59 44    12.400   12.346   84.6    4.6    99   27.5 
2026-09-21 00:00 UT   17 05 43.6   -51 56 56    12.421   12.352   83.7    4.6   100   27.5 
2026-09-22 00:00 UT   17 05 46.0   -51 54 09    12.442   12.358   82.9    4.6   100   27.5 
2026-09-23 00:00 UT   17 05 49.0   -51 51 24    12.463   12.364   82.0    4.6   101   27.5 
2026-09-24 00:00 UT   17 05 52.4   -51 48 40    12.484   12.370   81.2    4.6   101   27.5 
2026-09-25 00:00 UT   17 05 56.3   -51 45 57    12.505   12.376   80.3    4.6   101   27.5 
2026-09-26 00:00 UT   17 06 00.7   -51 43 16    12.526   12.382   79.4    4.6   102   27.6 
2026-09-27 00:00 UT   17 06 05.6   -51 40 37    12.547   12.388   78.6    4.5   102   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.