| 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) |
| 2026-07-29 00:00 |
00:11:08.27 |
-46:25:40.7 |
HIP 776 |
16.40 |
| 2026-07-29 12:00 |
00:11:00.41 |
-46:28:11.5 |
HIP 776 |
15.79 |
| 2026-07-30 00:00 |
00:10:52.44 |
-46:30:42.0 |
HIP 776 |
15.67 |
| 2026-07-30 12:00 |
00:10:44.36 |
-46:33:12.2 |
HIP 776 |
16.04 |
| 2026-07-31 00:00 |
00:10:36.16 |
-46:35:42.1 |
HIP 776 |
16.89 |
| 2026-07-31 12:00 |
00:10:27.84 |
-46:38:11.7 |
HIP 776 |
18.14 |
| 2026-08-01 00:00 |
00:10:19.42 |
-46:40:40.9 |
HIP 776 |
19.72 |
| 2026-08-01 12:00 |
00:10:10.88 |
-46:43:09.9 |
HIP 776 |
21.56 |
| 2026-08-02 00:00 |
00:10:02.23 |
-46:45:38.4 |
HIP 709 |
21.98 |
| 2026-08-02 12:00 |
00:09:53.47 |
-46:48:06.6 |
HIP 709 |
19.09 |
| 2026-08-03 00:00 |
00:09:44.59 |
-46:50:34.5 |
HIP 709 |
16.21 |
| 2026-08-03 12:00 |
00:09:35.61 |
-46:53:01.9 |
HIP 709 |
13.32 |
| 2026-08-04 00:00 |
00:09:26.51 |
-46:55:29.0 |
HIP 709 |
10.43 |
| 2026-08-04 12:00 |
00:09:17.31 |
-46:57:55.6 |
HIP 709 |
7.54 |
| 2026-08-05 00:00 |
00:09:07.99 |
-47:00:21.9 |
HIP 709 |
4.68 |
| 2026-08-05 12:00 |
00:08:58.57 |
-47:02:47.6 |
HIP 709 |
1.93 |
| 2026-08-06 00:00 |
00:08:49.04 |
-47:05:13.0 |
HIP 709 |
1.58 |
| 2026-08-06 12:00 |
00:08:39.40 |
-47:07:37.9 |
HIP 709 |
4.28 |
| 2026-08-07 00:00 |
00:08:29.65 |
-47:10:02.3 |
HIP 709 |
7.15 |
| 2026-08-07 12:00 |
00:08:19.79 |
-47:12:26.2 |
HIP 709 |
10.05 |
| 2026-08-08 00:00 |
00:08:09.83 |
-47:14:49.6 |
HIP 709 |
12.97 |
| 2026-08-08 12:00 |
00:07:59.77 |
-47:17:12.6 |
HIP 709 |
15.89 |
| 2026-08-09 00:00 |
00:07:49.60 |
-47:19:35.0 |
HIP 709 |
18.82 |
| 2026-08-09 12:00 |
00:07:39.32 |
-47:21:56.8 |
HIP 541 |
16.98 |
| 2026-08-10 00:00 |
00:07:28.95 |
-47:24:18.2 |
HIP 541 |
14.05 |
| 2026-08-10 12:00 |
00:07:18.47 |
-47:26:38.9 |
HIP 541 |
11.11 |
| 2026-08-11 00:00 |
00:07:07.88 |
-47:28:59.1 |
HIP 541 |
8.17 |
| 2026-08-11 12:00 |
00:06:57.20 |
-47:31:18.7 |
HIP 541 |
5.24 |
| 2026-08-12 00:00 |
00:06:46.42 |
-47:33:37.7 |
HIP 541 |
2.33 |
| 2026-08-12 12:00 |
00:06:35.53 |
-47:35:56.1 |
HIP 541 |
0.85 |
| 2026-08-13 00:00 |
00:06:24.55 |
-47:38:13.9 |
HIP 541 |
3.66 |
| 2026-08-13 12:00 |
00:06:13.47 |
-47:40:31.0 |
HIP 541 |
6.59 |
| 2026-08-14 00:00 |
00:06:02.30 |
-47:42:47.5 |
HIP 541 |
9.54 |
| 2026-08-14 12:00 |
00:05:51.03 |
-47:45:03.3 |
HIP 467 |
11.22 |
| 2026-08-15 00:00 |
00:05:39.66 |
-47:47:18.4 |
HIP 467 |
13.17 |
| 2026-08-15 12:00 |
00:05:28.21 |
-47:49:32.9 |
HIP 467 |
15.43 |
| 2026-08-16 00:00 |
00:05:16.66 |
-47:51:46.6 |
HIP 467 |
17.89 |
| 2026-08-16 12:00 |
00:05:05.01 |
-47:53:59.7 |
HIP 313 |
17.57 |
| 2026-08-17 00:00 |
00:04:53.28 |
-47:56:12.0 |
HIP 313 |
14.62 |
| 2026-08-17 12:00 |
00:04:41.46 |
-47:58:23.6 |
HIP 313 |
11.67 |
| 2026-08-18 00:00 |
00:04:29.55 |
-48:00:34.5 |
HIP 313 |
8.73 |
| 2026-08-18 12:00 |
00:04:17.55 |
-48:02:44.6 |
HIP 313 |
5.79 |
| 2026-08-19 00:00 |
00:04:05.47 |
-48:04:53.9 |
HIP 313 |
2.90 |