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	15 Oct 2026	27.6	12.500 AU	12.922 AU	17h08m	-50°56'	62.9°	4.1°	111°

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
2026-10-14 00:00 UT   17 08 35.7   -50 59 34    12.890   12.490   64.3    4.1   111   27.6 
2026-10-15 00:00 UT   17 08 48.2   -50 57 25    12.910   12.496   63.5    4.1   111   27.6 
2026-10-15 15:14 UT   17 08 56.3   -50 56 04    12.922   12.500   62.9    4.1   111   27.6 
2026-10-16 00:00 UT   17 09 01.0   -50 55 17    12.929   12.502   62.6    4.1   112   27.6 
2026-10-17 00:00 UT   17 09 14.2   -50 53 12    12.948   12.508   61.8    4.0   112   27.6 
2026-10-18 00:00 UT   17 09 27.7   -50 51 08    12.967   12.514   61.0    4.0   113   27.6 
2026-10-19 00:00 UT   17 09 41.6   -50 49 06    12.985   12.520   60.2    4.0   113   27.6 
2026-10-20 00:00 UT   17 09 55.8   -50 47 07    13.004   12.526   59.4    3.9   114   27.6 
2026-10-21 00:00 UT   17 10 10.4   -50 45 08    13.023   12.532   58.5    3.9   114   27.6 
2026-10-22 00:00 UT   17 10 25.2   -50 43 12    13.041   12.538   57.7    3.8   115   27.6 
2026-10-23 00:00 UT   17 10 40.4   -50 41 18    13.059   12.544   56.9    3.8   115   27.6 
2026-10-24 00:00 UT   17 10 55.9   -50 39 26    13.077   12.550   56.1    3.8   116   27.6 
2026-10-25 00:00 UT   17 11 11.7   -50 37 35    13.095   12.556   55.3    3.7   117   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.