| Parameter |
Value |
| Designation |
C/2023 H3 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2024-02-19T01:10:07.178880Z |
| Orbit solution date (soln_date, UTC) |
2025-07-31T12:12:22Z |
| Obs used |
69 |
| NEO |
- |
| M1 |
14.100 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2023-04-28T09:29:59.020800Z |
| Discovery magnitude (MPC) |
20.89 w |
| Discovery observatory (MPC) |
F52 · Pan-STARRS 2, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-09-20.0000000 |
| e |
0.61628192 |
| q (au) |
5.232368 |
| a (au) |
13.635969 |
| i (deg) |
2.489070 |
| Ω (om, deg) |
55.102603 |
| ω (w, deg) |
193.332545 |
| M (ma, deg) |
357.023830 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.936 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.936 |
| n |
2.000 |
| gf |
0.998 |
| gb |
-0.935 |
| k |
1.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
21:35:59.36 |
-16:38:59.2 |
HIP 106621 |
3.47 |
| 2026-03-26 12:00 |
21:36:17.25 |
-16:37:39.1 |
HIP 106621 |
7.92 |
| 2026-03-27 00:00 |
21:36:35.06 |
-16:36:19.2 |
HIP 106621 |
12.38 |
| 2026-03-27 12:00 |
21:36:52.78 |
-16:34:59.8 |
HIP 106621 |
16.82 |
| 2026-03-28 00:00 |
21:37:10.43 |
-16:33:40.6 |
HIP 106789 |
20.66 |
| 2026-03-28 12:00 |
21:37:28.00 |
-16:32:21.8 |
HIP 106789 |
17.91 |
| 2026-03-29 00:00 |
21:37:45.48 |
-16:31:03.4 |
HIP 106789 |
15.94 |
| 2026-03-29 12:00 |
21:38:02.89 |
-16:29:45.3 |
HIP 106789 |
15.03 |
| 2026-03-30 00:00 |
21:38:20.21 |
-16:28:27.6 |
HIP 106789 |
15.35 |
| 2026-03-30 12:00 |
21:38:37.45 |
-16:27:10.3 |
HIP 106789 |
16.83 |
| 2026-03-31 00:00 |
21:38:54.61 |
-16:25:53.3 |
HIP 106789 |
19.17 |
| 2026-03-31 12:00 |
21:39:11.68 |
-16:24:36.7 |
HIP 106985 |
19.85 |
| 2026-04-01 00:00 |
21:39:28.67 |
-16:23:20.5 |
HIP 106985 |
18.60 |
| 2026-04-01 12:00 |
21:39:45.57 |
-16:22:04.6 |
HIP 106985 |
18.28 |
| 2026-04-02 00:00 |
21:40:02.39 |
-16:20:49.1 |
HIP 106985 |
18.93 |
| 2026-04-02 12:00 |
21:40:19.13 |
-16:19:34.1 |
HIP 106985 |
20.44 |
| 2026-04-03 00:00 |
21:40:35.78 |
-16:18:19.4 |
HIP 106961 |
21.21 |
| 2026-04-03 12:00 |
21:40:52.34 |
-16:17:05.1 |
HIP 106961 |
22.63 |
| 2026-04-04 00:00 |
21:41:08.82 |
-16:15:51.2 |
HIP 106961 |
24.67 |
| 2026-04-04 12:00 |
21:41:25.21 |
-16:14:37.6 |
HIP 106961 |
27.18 |
| 2026-04-05 00:00 |
21:41:41.51 |
-16:13:24.6 |
HIP 106961 |
30.04 |
| 2026-04-05 12:00 |
21:41:57.72 |
-16:12:11.9 |
HIP 107176 |
27.85 |
| 2026-04-06 00:00 |
21:42:13.85 |
-16:10:59.6 |
HIP 107176 |
25.73 |
| 2026-04-06 12:00 |
21:42:29.88 |
-16:09:47.7 |
HIP 107176 |
24.11 |
| 2026-04-07 00:00 |
21:42:45.83 |
-16:08:36.3 |
HIP 107176 |
23.11 |
| 2026-04-07 12:00 |
21:43:01.68 |
-16:07:25.3 |
HIP 107324 |
20.68 |
| 2026-04-08 00:00 |
21:43:17.44 |
-16:06:14.7 |
HIP 107324 |
16.77 |
| 2026-04-08 12:00 |
21:43:33.12 |
-16:05:04.5 |
HIP 107324 |
12.92 |
| 2026-04-09 00:00 |
21:43:48.70 |
-16:03:54.8 |
HIP 107324 |
9.18 |
| 2026-04-09 12:00 |
21:44:04.18 |
-16:02:45.6 |
HIP 107324 |
5.70 |
| 2026-04-10 00:00 |
21:44:19.58 |
-16:01:36.7 |
HIP 107324 |
3.32 |
| 2026-04-10 12:00 |
21:44:34.88 |
-16:00:28.4 |
HIP 107324 |
4.42 |
| 2026-04-11 00:00 |
21:44:50.08 |
-15:59:20.4 |
HIP 107324 |
7.57 |
| 2026-04-11 12:00 |
21:45:05.19 |
-15:58:13.0 |
HIP 107324 |
11.13 |
| 2026-04-12 00:00 |
21:45:20.21 |
-15:57:06.0 |
HIP 107324 |
14.79 |
| 2026-04-12 12:00 |
21:45:35.13 |
-15:55:59.4 |
HIP 107324 |
18.47 |
| 2026-04-13 00:00 |
21:45:49.95 |
-15:54:53.4 |
HIP 107556 |
21.53 |
| 2026-04-13 12:00 |
21:46:04.68 |
-15:53:47.8 |
HIP 107556 |
19.55 |
| 2026-04-14 00:00 |
21:46:19.30 |
-15:52:42.7 |
HIP 107556 |
18.12 |
| 2026-04-14 12:00 |
21:46:33.83 |
-15:51:38.1 |
HIP 107556 |
17.36 |
| 2026-04-15 00:00 |
21:46:48.26 |
-15:50:33.9 |
HIP 107556 |
17.36 |
| 2026-04-15 12:00 |
21:47:02.59 |
-15:49:30.3 |
HIP 107556 |
18.09 |
| 2026-04-16 00:00 |
21:47:16.82 |
-15:48:27.1 |
HIP 107618 |
18.21 |