(404) Arsinoe
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	13 Dec 2025	14.8	2.974 AU	3.031 AU	22h59m	-21°22'	77.3°	18.8°
Opposition	15 Nov 2026	13.5	3.069 AU	2.098 AU	03h39m	+05°57'	166.8°	4.2°

The interactive orbit chart above shows the body'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 Arsinoe are:

            e (Eccentricity)                : 0.2016098
            a (Semimajor axis)              : 2.5918971
            i (Inclination)                 : 14.09820
            Ω (Longitude of ascending node) : 92.46743
            ω (Argument of perihelion)      : 120.51372
            M (Mean anomaly)                : 123.86510
            Epoch                           : 2025 Nov 21

            L (Longitude of perihelion)     : 33.75326
            B (Latitude of perihelion)      : 12.11356
            P (Orbital period in years)     : 4.17            
        

The light curve chart below shows the estimated development of the minor planet's magnitude.

The all-sky chart below shows the path of the minor planet over the same period as the light curve. The current position is marked yellow.

The following chart shows the path of the minor planet in the next few days. The field of view is optimized for (~10x50) binoculars and finderscopes.

Ephemerides:

Date       Time       RA (2000)    DEC (2000)    delta   radius  elong  phase   PA    magn
2025-12-13 00:00 UT   22 59 35.1   -21 22 57     3.031    2.974   77.3   18.8    70   14.8 
2025-12-13 03:15 UT   22 59 42.2   -21 21 43     3.033    2.974   77.2   18.8    70   14.8 
2025-12-14 00:00 UT   23 00 27.9   -21 13 51     3.046    2.975   76.5   18.8    70   14.8 
2025-12-15 00:00 UT   23 01 21.4   -21 04 43     3.061    2.976   75.8   18.7    70   14.9 
2025-12-16 00:00 UT   23 02 15.5   -20 55 32     3.075    2.978   75.1   18.6    70   14.9 
2025-12-17 00:00 UT   23 03 10.3   -20 46 19     3.090    2.979   74.3   18.5    71   14.9 
2025-12-18 00:00 UT   23 04 05.8   -20 37 04     3.104    2.980   73.6   18.5    71   14.9 
2025-12-19 00:00 UT   23 05 01.9   -20 27 46     3.119    2.981   72.9   18.4    71   14.9 
2025-12-20 00:00 UT   23 05 58.6   -20 18 27     3.133    2.983   72.1   18.3    71   14.9 
2025-12-21 00:00 UT   23 06 55.9   -20 09 05     3.148    2.984   71.4   18.2    71   14.9 
2025-12-22 00:00 UT   23 07 53.9   -19 59 42     3.162    2.985   70.7   18.1    71   14.9 
2025-12-23 00:00 UT   23 08 52.4   -19 50 16     3.177    2.986   70.0   18.0    71   14.9 
2025-12-24 00:00 UT   23 09 51.4   -19 40 49     3.191    2.988   69.3   17.9    72   14.9 
2025-12-25 00:00 UT   23 10 51.0   -19 31 20     3.205    2.989   68.5   17.8    72   14.9 
2025-12-26 00:00 UT   23 11 51.2   -19 21 49     3.219    2.990   67.8   17.7    72   14.9 
2025-12-27 00:00 UT   23 12 51.9   -19 12 16     3.233    2.991   67.1   17.6    72   15.0 
2025-12-28 00:00 UT   23 13 53.1   -19 02 42     3.247    2.992   66.4   17.5    72   15.0 
2025-12-29 00:00 UT   23 14 54.8   -18 53 07     3.261    2.994   65.7   17.4    72   15.0 
2025-12-30 00:00 UT   23 15 57.0   -18 43 29     3.275    2.995   65.0   17.3    73   15.0 
2025-12-31 00:00 UT   23 16 59.7   -18 33 51     3.289    2.996   64.3   17.2    73   15.0 
2026-01-01 00:00 UT   23 18 02.9   -18 24 11     3.302    2.997   63.6   17.1    73   15.0 
2026-01-02 00:00 UT   23 19 06.5   -18 14 30     3.316    2.998   62.9   17.0    73   15.0 
2026-01-03 00:00 UT   23 20 10.6   -18 04 47     3.329    2.999   62.2   16.9    73   15.0 
2026-01-04 00:00 UT   23 21 15.1   -17 55 03     3.343    3.001   61.5   16.7    73   15.0 
2026-01-05 00:00 UT   23 22 20.0   -17 45 18     3.356    3.002   60.8   16.6    73   15.0 
2026-01-06 00:00 UT   23 23 25.4   -17 35 32     3.369    3.003   60.1   16.5    74   15.0 
2026-01-07 00:00 UT   23 24 31.2   -17 25 44     3.383    3.004   59.4   16.4    74   15.0 
2026-01-08 00:00 UT   23 25 37.3   -17 15 56     3.396    3.005   58.7   16.2    74   15.0 
2026-01-09 00:00 UT   23 26 43.9   -17 06 06     3.409    3.006   58.0   16.1    74   15.0 
2026-01-10 00:00 UT   23 27 50.9   -16 56 15     3.422    3.007   57.4   16.0    74   15.0 
2026-01-11 00:00 UT   23 28 58.3   -16 46 23     3.434    3.009   56.7   15.9    74   15.0 

    Terminology:
            
    delta:  distance between minor planet and earth in AU
    radius: distance between minor planet 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-minor planet)    
    phase:  phase angle in degrees (angle sun-minor planet-earth)        
    AU:     Astronomical Unit (mean distance between earth and sun: 149597870.7 km
    

Orbital elements provided by 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.