2021 HY9
ephemeris	date	magn	radius	delta	ra	dec	elong	phase
Today	14 Nov 2025	32.5	3.177 AU	2.191 AU	02h55m	+21°57'	173.8°	1.9°

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 2021 HY9 are:

            e (Eccentricity)                : 0.5214603
            a (Semimajor axis)              : 2.0880417
            i (Inclination)                 : 11.40747
            Ω (Longitude of ascending node) : 31.67733
            ω (Argument of perihelion)      : 196.99218
            M (Mean anomaly)                : 184.11563
            Epoch                           : 2025 Nov 21

            L (Longitude of perihelion)     : 48.35264
            B (Latitude of perihelion)      : -3.31360
            P (Orbital period in years)     : 3.02            
        

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
2025-11-14 00:00 UT   02 55 41.1   +21 57 02     2.191    3.177  173.8    1.9   127   32.5 
2025-11-14 05:26 UT   02 55 24.8   +21 56 19     2.191    3.177  173.7    2.0   125   32.5 
2025-11-15 00:00 UT   02 54 29.2   +21 53 52     2.192    3.177  173.0    2.2   119   32.6 
2025-11-16 00:00 UT   02 53 17.5   +21 50 40     2.194    3.176  172.0    2.5   112   32.6 
2025-11-17 00:00 UT   02 52 06.3   +21 47 24     2.196    3.176  171.0    2.8   107   32.6 
2025-11-18 00:00 UT   02 50 55.6   +21 44 06     2.198    3.176  169.9    3.1   103   32.6 
2025-11-19 00:00 UT   02 49 45.4   +21 40 45     2.201    3.176  168.7    3.5   100   32.7 
2025-11-20 00:00 UT   02 48 35.8   +21 37 21     2.204    3.176  167.5    3.8    97   32.7 
2025-11-21 00:00 UT   02 47 26.9   +21 33 56     2.207    3.176  166.4    4.2    95   32.7 
2025-11-22 00:00 UT   02 46 18.7   +21 30 29     2.210    3.175  165.2    4.6    93   32.7 
2025-11-23 00:00 UT   02 45 11.4   +21 27 01     2.214    3.175  164.0    4.9    91   32.8 
2025-11-24 00:00 UT   02 44 04.8   +21 23 32     2.219    3.175  162.7    5.3    90   32.8 
2025-11-25 00:00 UT   02 42 59.2   +21 20 02     2.223    3.175  161.5    5.7    88   32.8 
2025-11-26 00:00 UT   02 41 54.5   +21 16 32     2.228    3.175  160.3    6.0    87   32.8 
2025-11-27 00:00 UT   02 40 50.8   +21 13 02     2.233    3.174  159.1    6.4    86   32.8 
2025-11-28 00:00 UT   02 39 48.2   +21 09 31     2.238    3.174  157.8    6.7    85   32.9 
2025-11-29 00:00 UT   02 38 46.6   +21 06 02     2.244    3.174  156.6    7.1    85   32.9 
2025-11-30 00:00 UT   02 37 46.2   +21 02 33     2.250    3.173  155.4    7.4    84   32.9 
2025-12-01 00:00 UT   02 36 47.0   +20 59 05     2.256    3.173  154.2    7.8    83   32.9 
2025-12-02 00:00 UT   02 35 49.0   +20 55 38     2.263    3.173  152.9    8.1    83   32.9 
2025-12-03 00:00 UT   02 34 52.2   +20 52 13     2.269    3.172  151.7    8.5    82   33.0 
2025-12-04 00:00 UT   02 33 56.7   +20 48 50     2.277    3.172  150.5    8.8    81   33.0 
2025-12-05 00:00 UT   02 33 02.6   +20 45 29     2.284    3.171  149.3    9.1    81   33.0 
2025-12-06 00:00 UT   02 32 09.8   +20 42 11     2.292    3.171  148.1    9.5    80   33.0 
2025-12-07 00:00 UT   02 31 18.3   +20 38 55     2.299    3.171  146.9    9.8    80   33.1 
2025-12-08 00:00 UT   02 30 28.3   +20 35 42     2.308    3.170  145.7   10.1    80   33.1 
2025-12-09 00:00 UT   02 29 39.6   +20 32 32     2.316    3.170  144.5   10.4    79   33.1 
2025-12-10 00:00 UT   02 28 52.5   +20 29 26     2.325    3.169  143.3   10.7    79   33.1 
2025-12-11 00:00 UT   02 28 06.7   +20 26 23     2.333    3.169  142.1   11.0    79   33.1 
2025-12-12 00:00 UT   02 27 22.5   +20 23 24     2.342    3.168  140.9   11.3    78   33.2 
2025-12-13 00:00 UT   02 26 39.8   +20 20 29     2.352    3.168  139.7   11.6    78   33.2 
2025-12-14 00:00 UT   02 25 58.6   +20 17 38     2.361    3.167  138.6   11.9    78   33.2 

    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.