C/2019 K4 (Ye)
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	15 Jun 2019	16.8	2.274 AU	2.717 AU	01h26m	+42°59'	54.1°	21.2°	270°
Nearest approach	17 Sep 2019	16.0	2.508 AU	1.523 AU	00h13m	+09°10'	165.1°	5.9°	219°
Today	15 May 2026	30.0	18.378 AU	18.098 AU	08h15m	-77°14'	104.5°	3.1°	112°

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 11.1 + 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 K4 (Ye) are:

    e (Eccentricity)                : 0.9986680
    q (Perihelion distance)         : 2.2743820
    i (Inclination)                 : 105.27620
    Ω (Longitude of ascending node) : 180.38840
    ω (Argument of perihelion)      : 140.03360
    L (Longitude of perihelion)     : 192.84043
    B (Latitude of perihelion)      : 38.29003
    T (Time of perihelion passage)  : 2458650.06690
    P (Orbital period in years)     : 70556.78

    Epoch                           : 2026 May 14
    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
2026-05-14 00:00 UT   08 15 15.6   -77 19 28    18.090   18.369  104.5    3.1   110   30.0 
2026-05-15 00:00 UT   08 15 42.8   -77 16 15    18.095   18.375  104.5    3.1   111   30.0 
2026-05-15 14:15 UT   08 15 59.3   -77 14 21    18.098   18.378  104.5    3.1   112   30.0 
2026-05-16 00:00 UT   08 16 10.7   -77 13 03    18.100   18.380  104.5    3.1   112   30.0 
2026-05-17 00:00 UT   08 16 39.3   -77 09 52    18.105   18.385  104.6    3.1   113   30.0 
2026-05-18 00:00 UT   08 17 08.4   -77 06 42    18.109   18.391  104.6    3.1   114   30.0 
2026-05-19 00:00 UT   08 17 38.2   -77 03 34    18.114   18.396  104.6    3.1   115   30.0 
2026-05-20 00:00 UT   08 18 08.6   -77 00 26    18.119   18.401  104.6    3.1   116   30.0 
2026-05-21 00:00 UT   08 18 39.7   -76 57 20    18.125   18.407  104.6    3.0   116   30.0 
2026-05-22 00:00 UT   08 19 11.2   -76 54 15    18.130   18.412  104.6    3.0   117   30.0 
2026-05-23 00:00 UT   08 19 43.4   -76 51 12    18.135   18.417  104.6    3.0   118   30.0 
2026-05-24 00:00 UT   08 20 16.1   -76 48 10    18.141   18.422  104.6    3.0   119   30.0 
2026-05-25 00:00 UT   08 20 49.3   -76 45 09    18.146   18.428  104.6    3.0   120   30.0 

    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.