C/2019 Y4-B (ATLAS) - DISINTEGRATED
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Disintegration	12 May 2020	8.6	0.573 AU	0.805 AU	04h06m	+51°12'	34.5°	92.8°	21°
Nearest approach	20 May 2020	8.1	0.384 AU	0.773 AU	03h35m	+39°21'	19.6°	118.1°	351°
Perihelion	28 May 2020	7.2	0.258 AU	0.875 AU	03h27m	+19°22'	13.3°	115.5°	258°
Today	30 May 2026	-	18.014 AU	18.782 AU	07h09m	+11°51'	39.7°	2.1°	110°

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. This lightcurve is being recalculated every 6 hours based on the available COBS/MPC observations (currently 11.6 + 5 log[∆] + 10.0 log[r]). An additional green curve is displayed when an increase in apparent brightness is expected due to forward scattering of sunlight, which occurs when a dust-rich comet is located between the Earth and the Sun. (See Marcus 2007)

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 C/2019 Y4-B (ATLAS) are:

    e (Eccentricity)                : 0.9977730
    q (Perihelion distance)         : 0.2580420
    i (Inclination)                 : 44.68940
    Ω (Longitude of ascending node) : 120.67790
    ω (Argument of perihelion)      : 177.45640
    L (Longitude of perihelion)     : 118.86899
    B (Latitude of perihelion)      : 1.78852
    T (Time of perihelion passage)  : 2458998.29190
    P (Orbital period in years)     : 1247.26

    Epoch                           : 2026 May 29
    Reference                       : MPC194165

    Classification(s):              : Nearly isotropic; Returning (a < 10000 AU); External (P > 200 years)

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-05-29 00:00 UT   07 09 13.7   +11 50 54    18.756   18.005   41.1    2.1   109   30.5 
2026-05-30 00:00 UT   07 09 24.1   +11 51 02    18.772   18.011   40.2    2.1   110   30.5 
2026-05-30 13:51 UT   07 09 30.1   +11 51 07    18.782   18.014   39.7    2.1   110   30.5 
2026-05-31 00:00 UT   07 09 34.6   +11 51 10    18.788   18.016   39.3    2.0   110   30.5 
2026-06-01 00:00 UT   07 09 45.2   +11 51 17    18.804   18.022   38.4    2.0   111   30.5 
2026-06-02 00:00 UT   07 09 55.9   +11 51 23    18.820   18.027   37.6    2.0   111   30.5 
2026-06-03 00:00 UT   07 10 06.7   +11 51 28    18.835   18.032   36.7    1.9   111   30.5 
2026-06-04 00:00 UT   07 10 17.7   +11 51 33    18.850   18.038   35.8    1.9   112   30.5 
2026-06-05 00:00 UT   07 10 28.7   +11 51 37    18.865   18.043   35.0    1.8   112   30.5 
2026-06-06 00:00 UT   07 10 39.8   +11 51 41    18.880   18.049   34.1    1.8   113   30.5 
2026-06-07 00:00 UT   07 10 51.0   +11 51 43    18.894   18.054   33.2    1.8   113   30.5 
2026-06-08 00:00 UT   07 11 02.3   +11 51 45    18.908   18.060   32.4    1.7   114   30.5 
2026-06-09 00:00 UT   07 11 13.7   +11 51 46    18.922   18.065   31.5    1.7   115   30.5 

    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.