P/2025 UX109
ephemeris	date	magn	radius	delta	ra	dec	elong	phase	PA
Perihelion	14 Aug 2025	20.5	2.570 AU	3.500 AU	08h13m	+17°30'	19.8°	7.7°	276°
Nearest approach	28 Feb 2026	19.5	2.827 AU	1.845 AU	11h13m	+02°10'	170.6°	3.3°	309°
Today	19 Mar 2026	19.7	2.875 AU	1.900 AU	11h00m	+03°54'	165.6°	5.0°	104°

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 light curve is based on the absolute magnitude and slope parameter as calculated from an MPEC, or the latest values provided by the minor planet center. (13.7 + 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 P/2025 UX109 are:

    e (Eccentricity)                : 0.3245560
    q (Perihelion distance)         : 2.5698690
    i (Inclination)                 : 3.18140
    Ω (Longitude of ascending node) : 197.98230
    ω (Argument of perihelion)      : 276.12490
    L (Longitude of perihelion)     : 114.11658
    B (Latitude of perihelion)      : -3.16322
    T (Time of perihelion passage)  : 2460901.73310
    P (Orbital period in years)     : 7.42

    Epoch                           : 2026 Mar 19
    Reference                       : MPEC 2026-EC7

    Classification(s):              : Ecliptic; Jupiter family
    Tisserand (Jupiter)             : 2.983

Ephemerides

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2026-03-18 00:00 UT   11 01 17.0   +03 44 39     1.890    2.870  167.8    4.2   102   19.7 
2026-03-19 00:00 UT   11 00 40.4   +03 49 48     1.895    2.873  166.6    4.6   103   19.7 
2026-03-19 22:37 UT   11 00 06.4   +03 54 37     1.900    2.875  165.6    5.0   104   19.7 
2026-03-20 00:00 UT   11 00 04.4   +03 54 54     1.900    2.875  165.5    5.0   104   19.7 
2026-03-21 00:00 UT   10 59 29.1   +03 59 56     1.906    2.878  164.3    5.4   104   19.7 
2026-03-22 00:00 UT   10 58 54.6   +04 04 54     1.912    2.880  163.2    5.7   105   19.7 
2026-03-23 00:00 UT   10 58 20.9   +04 09 47     1.918    2.883  162.1    6.1   106   19.7 
2026-03-24 00:00 UT   10 57 48.0   +04 14 36     1.924    2.885  160.9    6.5   106   19.7 
2026-03-25 00:00 UT   10 57 15.9   +04 19 20     1.931    2.888  159.8    6.9   107   19.7 
2026-03-26 00:00 UT   10 56 44.8   +04 23 59     1.938    2.890  158.7    7.2   107   19.7 
2026-03-27 00:00 UT   10 56 14.6   +04 28 32     1.945    2.893  157.5    7.6   107   19.8 
2026-03-28 00:00 UT   10 55 45.4   +04 32 60     1.953    2.895  156.4    7.9   108   19.8 
2026-03-29 00:00 UT   10 55 17.2   +04 37 22     1.961    2.898  155.3    8.3   108   19.8 

    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.