| 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 |
0.999 |
| 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 |
+5.2262 |
-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) |
| 2026-09-20 00:00 |
23:49:09.55 |
-49:49:34.4 |
HIP 117327 |
21.57 |
| 2026-09-20 12:00 |
23:48:54.66 |
-49:50:36.2 |
HIP 117327 |
20.42 |
| 2026-09-21 00:00 |
23:48:39.77 |
-49:51:36.8 |
HIP 117327 |
19.54 |
| 2026-09-21 12:00 |
23:48:24.88 |
-49:52:36.2 |
HIP 117327 |
18.96 |
| 2026-09-22 00:00 |
23:48:10.01 |
-49:53:34.3 |
HIP 117327 |
18.71 |
| 2026-09-22 12:00 |
23:47:55.15 |
-49:54:31.2 |
HIP 117228 |
17.26 |
| 2026-09-23 00:00 |
23:47:40.30 |
-49:55:26.9 |
HIP 117228 |
14.80 |
| 2026-09-23 12:00 |
23:47:25.47 |
-49:56:21.4 |
HIP 117228 |
12.38 |
| 2026-09-24 00:00 |
23:47:10.65 |
-49:57:14.6 |
HIP 117228 |
10.04 |
| 2026-09-24 12:00 |
23:46:55.85 |
-49:58:06.6 |
HIP 117228 |
7.82 |
| 2026-09-25 00:00 |
23:46:41.08 |
-49:58:57.4 |
HIP 117228 |
5.86 |
| 2026-09-25 12:00 |
23:46:26.32 |
-49:59:47.0 |
HIP 117228 |
4.49 |
| 2026-09-26 00:00 |
23:46:11.58 |
-50:00:35.3 |
HIP 117228 |
4.29 |
| 2026-09-26 12:00 |
23:45:56.87 |
-50:01:22.4 |
HIP 117228 |
5.38 |
| 2026-09-27 00:00 |
23:45:42.18 |
-50:02:08.3 |
HIP 117228 |
7.19 |
| 2026-09-27 12:00 |
23:45:27.52 |
-50:02:52.9 |
HIP 117228 |
9.29 |
| 2026-09-28 00:00 |
23:45:12.89 |
-50:03:36.3 |
HIP 117228 |
11.53 |
| 2026-09-28 12:00 |
23:44:58.29 |
-50:04:18.5 |
HIP 117228 |
13.82 |
| 2026-09-29 00:00 |
23:44:43.72 |
-50:04:59.5 |
HIP 117228 |
16.15 |
| 2026-09-29 12:00 |
23:44:29.18 |
-50:05:39.2 |
HIP 117228 |
18.48 |
| 2026-09-30 00:00 |
23:44:14.68 |
-50:06:17.8 |
HIP 117228 |
20.83 |
| 2026-09-30 12:00 |
23:44:00.21 |
-50:06:55.0 |
HIP 116919 |
21.69 |
| 2026-10-01 00:00 |
23:43:45.78 |
-50:07:31.1 |
HIP 116919 |
19.34 |
| 2026-10-01 12:00 |
23:43:31.39 |
-50:08:05.9 |
HIP 116919 |
17.01 |
| 2026-10-02 00:00 |
23:43:17.03 |
-50:08:39.6 |
HIP 116919 |
14.72 |
| 2026-10-02 12:00 |
23:43:02.72 |
-50:09:12.0 |
HIP 116919 |
12.47 |
| 2026-10-03 00:00 |
23:42:48.46 |
-50:09:43.1 |
HIP 116919 |
10.29 |
| 2026-10-03 12:00 |
23:42:34.23 |
-50:10:13.1 |
HIP 116919 |
8.22 |
| 2026-10-04 00:00 |
23:42:20.06 |
-50:10:41.8 |
HIP 116919 |
6.35 |
| 2026-10-04 12:00 |
23:42:05.93 |
-50:11:09.3 |
HIP 116919 |
4.91 |
| 2026-10-05 00:00 |
23:41:51.85 |
-50:11:35.6 |
HIP 116919 |
4.31 |
| 2026-10-05 12:00 |
23:41:37.82 |
-50:12:00.7 |
HIP 116919 |
4.88 |
| 2026-10-06 00:00 |
23:41:23.84 |
-50:12:24.5 |
HIP 116919 |
6.28 |
| 2026-10-06 12:00 |
23:41:09.91 |
-50:12:47.1 |
HIP 116919 |
8.08 |
| 2026-10-07 00:00 |
23:40:56.05 |
-50:13:08.6 |
HIP 116919 |
10.07 |
| 2026-10-07 12:00 |
23:40:42.23 |
-50:13:28.8 |
HIP 116919 |
12.14 |
| 2026-10-08 00:00 |
23:40:28.48 |
-50:13:47.8 |
HIP 116919 |
14.25 |
| 2026-10-08 12:00 |
23:40:14.78 |
-50:14:05.6 |
HIP 116919 |
16.39 |
| 2026-10-09 00:00 |
23:40:01.15 |
-50:14:22.2 |
HIP 116919 |
18.53 |
| 2026-10-09 12:00 |
23:39:47.58 |
-50:14:37.6 |
HIP 116919 |
20.68 |
| 2026-10-10 00:00 |
23:39:34.07 |
-50:14:51.8 |
HIP 116894 |
22.48 |
| 2026-10-10 12:00 |
23:39:20.63 |
-50:15:04.8 |
HIP 116894 |
24.30 |
| 2026-10-11 00:00 |
23:39:07.26 |
-50:15:16.7 |
HIP 116894 |
26.17 |