| Parameter |
Value |
| Designation |
C/2022 A2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-02-18T06:27:19.474560Z |
| Orbit solution date (soln_date, UTC) |
2024-08-02T01:42:20Z |
| Obs used |
2731 |
| NEO |
- |
| M1 |
8.300 |
| K1 |
11.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2022-01-10T14:49:09.494400Z |
| Discovery magnitude (MPC) |
20.51 w |
| Discovery observatory (MPC) |
F52 · Pan-STARRS 2, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-04-25.0000000 |
| e |
1.00038112 |
| q (au) |
1.735334 |
| a (au) |
-4553.263121 |
| i (deg) |
108.146714 |
| Ω (om, deg) |
171.579526 |
| ω (w, deg) |
88.367878 |
| M (ma, deg) |
0.000211 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.794 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.794 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.798 |
| k |
0.997 |
| δ90 |
10.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2022-01-09 |
2023-02-17 |
+2.8312 |
-1.497 |
| 2023-02-18 |
2023-08-21 |
+5.2261 |
-2.663 |
| 2023-08-21 |
2024-08-01 |
-3.9154 |
+1.262 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
23:50:45.06 |
-39:52:51.7 |
HIP 117771 |
27.40 |
| 2026-03-26 12:00 |
23:50:57.88 |
-39:52:46.5 |
HIP 117771 |
25.09 |
| 2026-03-27 00:00 |
23:51:10.69 |
-39:52:42.2 |
HIP 117771 |
22.80 |
| 2026-03-27 12:00 |
23:51:23.47 |
-39:52:38.7 |
HIP 117771 |
20.56 |
| 2026-03-28 00:00 |
23:51:36.24 |
-39:52:36.0 |
HIP 117771 |
18.36 |
| 2026-03-28 12:00 |
23:51:48.99 |
-39:52:34.2 |
HIP 117771 |
16.23 |
| 2026-03-29 00:00 |
23:52:01.72 |
-39:52:33.2 |
HIP 117771 |
14.19 |
| 2026-03-29 12:00 |
23:52:14.43 |
-39:52:33.0 |
HIP 117771 |
12.30 |
| 2026-03-30 00:00 |
23:52:27.12 |
-39:52:33.6 |
HIP 117771 |
10.62 |
| 2026-03-30 12:00 |
23:52:39.78 |
-39:52:35.1 |
HIP 117771 |
9.27 |
| 2026-03-31 00:00 |
23:52:52.43 |
-39:52:37.4 |
HIP 117771 |
8.41 |
| 2026-03-31 12:00 |
23:53:05.06 |
-39:52:40.6 |
HIP 117771 |
8.18 |
| 2026-04-01 00:00 |
23:53:17.66 |
-39:52:44.5 |
HIP 117771 |
8.64 |
| 2026-04-01 12:00 |
23:53:30.24 |
-39:52:49.4 |
HIP 117771 |
9.68 |
| 2026-04-02 00:00 |
23:53:42.79 |
-39:52:55.1 |
HIP 117771 |
11.15 |
| 2026-04-02 12:00 |
23:53:55.32 |
-39:53:01.6 |
HIP 117771 |
12.88 |
| 2026-04-03 00:00 |
23:54:07.83 |
-39:53:09.0 |
HIP 117771 |
14.80 |
| 2026-04-03 12:00 |
23:54:20.31 |
-39:53:17.2 |
HIP 117943 |
14.41 |
| 2026-04-04 00:00 |
23:54:32.76 |
-39:53:26.3 |
HIP 117943 |
12.52 |
| 2026-04-04 12:00 |
23:54:45.19 |
-39:53:36.2 |
HIP 117943 |
10.84 |
| 2026-04-05 00:00 |
23:54:57.59 |
-39:53:47.0 |
HIP 117943 |
9.49 |
| 2026-04-05 12:00 |
23:55:09.96 |
-39:53:58.6 |
HIP 117943 |
8.61 |
| 2026-04-06 00:00 |
23:55:22.31 |
-39:54:11.1 |
HIP 117943 |
8.36 |
| 2026-04-06 12:00 |
23:55:34.63 |
-39:54:24.5 |
HIP 117943 |
8.79 |
| 2026-04-07 00:00 |
23:55:46.91 |
-39:54:38.7 |
HIP 117943 |
9.80 |
| 2026-04-07 12:00 |
23:55:59.17 |
-39:54:53.8 |
HIP 117943 |
11.23 |
| 2026-04-08 00:00 |
23:56:11.40 |
-39:55:09.8 |
HIP 117943 |
12.95 |
| 2026-04-08 12:00 |
23:56:23.59 |
-39:55:26.7 |
HIP 117943 |
14.85 |
| 2026-04-09 00:00 |
23:56:35.76 |
-39:55:44.4 |
HIP 117943 |
16.87 |
| 2026-04-09 12:00 |
23:56:47.89 |
-39:56:03.0 |
HIP 117943 |
18.97 |
| 2026-04-10 00:00 |
23:56:59.98 |
-39:56:22.4 |
HIP 117943 |
21.13 |
| 2026-04-10 12:00 |
23:57:12.05 |
-39:56:42.8 |
HIP 117943 |
23.32 |
| 2026-04-11 00:00 |
23:57:24.08 |
-39:57:04.0 |
HIP 117943 |
25.54 |
| 2026-04-11 12:00 |
23:57:36.08 |
-39:57:26.1 |
HIP 117943 |
27.77 |
| 2026-04-12 00:00 |
23:57:48.04 |
-39:57:49.1 |
HIP 117943 |
30.02 |
| 2026-04-12 12:00 |
23:57:59.96 |
-39:58:13.0 |
HIP 17 |
28.60 |
| 2026-04-13 00:00 |
23:58:11.85 |
-39:58:37.8 |
HIP 17 |
26.40 |
| 2026-04-13 12:00 |
23:58:23.70 |
-39:59:03.5 |
HIP 17 |
24.23 |
| 2026-04-14 00:00 |
23:58:35.51 |
-39:59:30.1 |
HIP 17 |
22.08 |
| 2026-04-14 12:00 |
23:58:47.28 |
-39:59:57.5 |
HIP 17 |
19.96 |
| 2026-04-15 00:00 |
23:58:59.02 |
-40:00:25.9 |
HIP 17 |
17.88 |
| 2026-04-15 12:00 |
23:59:10.71 |
-40:00:55.2 |
HIP 17 |
15.85 |
| 2026-04-16 00:00 |
23:59:22.37 |
-40:01:25.3 |
HIP 17 |
13.91 |