C/2021 A4 (NEOWISE)
ephemeris date magn radius delta ra dec elong phase PA
Nearest approach12 Feb 202112.31.275 AU0.434 AU06h39m+60°12'122.7°40.7°124°
Perihelion20 Mar 202113.91.146 AU1.145 AU04h14m-01°59'64.3°51.5°91°
Today20 Oct 202120.33.140 AU2.900 AU22h04m-65°30'94.5°18.4°53°
C/2021 A4 (NEOWISE)- 2021-10-20

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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.)

The orbital elements of C/2021 A4 (NEOWISE) are:

            e (eccentricity)                : 0.9733440
            q (perihelion distance)         : 1.1456900
            i (inclination)                 : 111.56940
            Ω (Longitude of ascending node) : 307.08650
            ω (Argument of perihelion)      : 204.67040
            L (Longitude of perihelion)     : 297.50195
            B (Latitude of perihelion)      : -22.84059
            T (Time of perihelion passage)  : 2459293.53060
            P (Orbital period in years)     : 281.78

            Epoch                           : 2021 Oct 19
            Reference                       : MPEC 2021-R75

            Classification(s):              : Nearly isotropic; External (a < 10000 AU)

The light curve chart below shows the estimated development of the comet's magnitude. Blue and black dots are visual and photometric CCD observations respectively from COBS or the MPC. The gray curve is based on the absolute magnitude and slope parameter as calculated from the original MPEC, or the latest values provided by the MPC (16.00 + 5 log[∆] + 10.00 log[r]), whereas the red curve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 13.04 + 5 log[∆] + 10.00 log[r]).

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.