C/2019 Y4-B (ATLAS) - DISINTEGRATED
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Disintegration	12 May 2020	8.6	0.574 AU	0.805 AU	04h06m	+51°15'	34.6°	92.7°	21°
Nearest approach	20 May 2020	8.1	0.384 AU	0.773 AU	03h35m	+39°20'	19.6°	118.1°	351°
Perihelion	28 May 2020	7.2	0.258 AU	0.875 AU	03h27m	+19°23'	13.3°	115.5°	258°
Today	16 May 2026	-	17.936 AU	18.536 AU	07h07m	+11°48'	52.3°	2.6°	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. 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)                : 0.9977740
    q (Perihelion distance)         : 0.2580750
    i (Inclination)                 : 44.68930
    Ω (Longitude of ascending node) : 120.67800
    ω (Argument of perihelion)      : 177.45760
    L (Longitude of perihelion)     : 118.86994
    B (Latitude of perihelion)      : 1.78768
    T (Time of perihelion passage)  : 2458998.32840
    P (Orbital period in years)     : 1248.34

    Epoch                           : 2026 May 15
    Reference                       : MPEC 2026-E44

    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
2026-05-15 00:00 UT   07 07 01.6   +11 47 42    18.509   17.929   53.6    2.6   105   30.4 
2026-05-16 00:00 UT   07 07 10.1   +11 48 00    18.528   17.934   52.7    2.6   105   30.4 
2026-05-16 09:58 UT   07 07 13.7   +11 48 07    18.536   17.936   52.3    2.6   105   30.4 
2026-05-17 00:00 UT   07 07 18.8   +11 48 18    18.547   17.939   51.8    2.5   105   30.4 
2026-05-18 00:00 UT   07 07 27.6   +11 48 35    18.565   17.945   50.9    2.5   106   30.4 
2026-05-19 00:00 UT   07 07 36.6   +11 48 51    18.583   17.950   50.0    2.5   106   30.4 
2026-05-20 00:00 UT   07 07 45.7   +11 49 07    18.602   17.956   49.1    2.4   106   30.4 
2026-05-21 00:00 UT   07 07 54.9   +11 49 21    18.619   17.961   48.2    2.4   106   30.4 
2026-05-22 00:00 UT   07 08 04.3   +11 49 36    18.637   17.967   47.3    2.4   107   30.4 
2026-05-23 00:00 UT   07 08 13.9   +11 49 49    18.655   17.972   46.4    2.3   107   30.4 
2026-05-24 00:00 UT   07 08 23.5   +11 50 02    18.672   17.978   45.5    2.3   107   30.5 
2026-05-25 00:00 UT   07 08 33.3   +11 50 14    18.689   17.983   44.6    2.3   108   30.5 
2026-05-26 00:00 UT   07 08 43.2   +11 50 25    18.706   17.989   43.7    2.2   108   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.