|
C/2021 A9 (PANSTARRS) |
| ephemeris |
date |
magn |
radius |
delta |
ra |
dec |
elong |
phase |
PA |
| Perihelion | 4 Dec 2023 | 19.1 | 7.765 AU | 6.983 AU | 07h17m | +09°30' | 140.2° | 4.7° | 293° |
| Nearest approach | 3 Jan 2024 | 19.1 | 7.768 AU | 6.809 AU | 06h52m | +09°09' | 166.3° | 1.7° | 2° |
| Today | 29 Nov 2025 | 20.0 | 8.937 AU | 8.029 AU | 04h15m | -02°45' | 155.7° | 2.6° | 3° |
C/2021 A9 (PANSTARRS)- 2025-11-29
astro.vanbuitenen.nl
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. (6.0 + 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/2021 A9 (PANSTARRS) are:
e (Eccentricity) : 0.9998220
q (Perihelion distance) : 7.7653340
i (Inclination) : 158.01780
Ω (Longitude of ascending node) : 314.85150
ω (Argument of perihelion) : 211.66370
L (Longitude of perihelion) : 285.08622
B (Latitude of perihelion) : -11.33189
T (Time of perihelion passage) : 2460282.82690
Epoch : 2025 Nov 28
Reference : MPEC 2025-WD0
Classification(s): : Nearly isotropic; New (a > 10000 AU)
Ephemerides
Date Time RA (2000) DEC (2000) delta radius elong phase PA magn
2025-11-28 00:00 UT 04 16 05.6 -02 43 23 8.023 8.934 156.0 2.6 359 20.0
2025-11-29 00:00 UT 04 15 23.7 -02 45 26 8.027 8.936 155.8 2.6 2 20.0
2025-11-29 06:27 UT 04 15 12.4 -02 45 58 8.029 8.937 155.7 2.6 3 20.0
2025-11-30 00:00 UT 04 14 41.9 -02 47 25 8.032 8.939 155.5 2.6 5 20.0
2025-12-01 00:00 UT 04 14 00.1 -02 49 20 8.037 8.942 155.2 2.7 8 20.0
2025-12-02 00:00 UT 04 13 18.5 -02 51 12 8.043 8.945 154.8 2.7 10 20.0
2025-12-03 00:00 UT 04 12 36.9 -02 53 01 8.049 8.948 154.4 2.7 13 20.0
2025-12-04 00:00 UT 04 11 55.4 -02 54 46 8.055 8.951 153.9 2.8 15 20.0
2025-12-05 00:00 UT 04 11 14.1 -02 56 28 8.062 8.954 153.4 2.8 18 20.1
2025-12-06 00:00 UT 04 10 32.9 -02 58 06 8.069 8.957 152.9 2.9 20 20.1
2025-12-07 00:00 UT 04 09 51.9 -02 59 40 8.076 8.960 152.3 2.9 22 20.1
2025-12-08 00:00 UT 04 09 11.0 -03 01 11 8.084 8.963 151.7 3.0 24 20.1
2025-12-09 00:00 UT 04 08 30.3 -03 02 38 8.092 8.966 151.0 3.1 26 20.1
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.
