| Parameter |
Value |
| Designation |
323P/SOHO |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-01-17T15:09:04.803840Z |
| Orbit solution date (soln_date, UTC) |
2025-02-20T14:38:09Z |
| Obs used |
171 |
| NEO |
Yes |
| M1 |
23.400 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-03-03.0000000 |
| e |
0.98481410 |
| q (au) |
0.039207 |
| a (au) |
2.581828 |
| i (deg) |
5.369972 |
| Ω (om, deg) |
324.229171 |
| ω (w, deg) |
353.174495 |
| M (ma, deg) |
10.541190 |
Magnitude
Scatter + Global Linear
$$
M_a = (20.000 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
20.000 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2025-01-27 |
2025-02-08 |
-17.3579 |
+3.208 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
08:24:19.99 |
+20:11:49.1 |
HIP 41232 |
7.34 |
| 2026-06-01 12:00 |
08:24:36.29 |
+20:10:47.6 |
HIP 41232 |
3.43 |
| 2026-06-02 00:00 |
08:24:52.69 |
+20:09:45.8 |
HIP 41232 |
1.01 |
| 2026-06-02 12:00 |
08:25:09.18 |
+20:08:43.5 |
HIP 41232 |
4.72 |
| 2026-06-03 00:00 |
08:25:25.78 |
+20:07:40.9 |
HIP 41232 |
8.72 |
| 2026-06-03 12:00 |
08:25:42.47 |
+20:06:37.9 |
HIP 41334 |
6.35 |
| 2026-06-04 00:00 |
08:25:59.26 |
+20:05:34.5 |
HIP 41334 |
6.03 |
| 2026-06-04 12:00 |
08:26:16.14 |
+20:04:30.7 |
HIP 41334 |
8.13 |
| 2026-06-05 00:00 |
08:26:33.11 |
+20:03:26.5 |
HIP 41334 |
11.39 |
| 2026-06-05 12:00 |
08:26:50.18 |
+20:02:21.9 |
HIP 41334 |
15.11 |
| 2026-06-06 00:00 |
08:27:07.34 |
+20:01:16.9 |
HIP 41334 |
19.03 |
| 2026-06-06 12:00 |
08:27:24.58 |
+20:00:11.6 |
HIP 41334 |
23.06 |
| 2026-06-07 00:00 |
08:27:41.92 |
+19:59:05.9 |
HIP 41334 |
27.16 |
| 2026-06-07 12:00 |
08:27:59.35 |
+19:57:59.8 |
HIP 41334 |
31.31 |
| 2026-06-08 00:00 |
08:28:16.86 |
+19:56:53.3 |
HIP 41638 |
33.29 |
| 2026-06-08 12:00 |
08:28:34.45 |
+19:55:46.4 |
HIP 41638 |
32.47 |
| 2026-06-09 00:00 |
08:28:52.14 |
+19:54:39.2 |
HIP 41638 |
32.20 |
| 2026-06-09 12:00 |
08:29:09.90 |
+19:53:31.6 |
HIP 41638 |
32.51 |
| 2026-06-10 00:00 |
08:29:27.75 |
+19:52:23.6 |
HIP 41638 |
33.39 |
| 2026-06-10 12:00 |
08:29:45.68 |
+19:51:15.3 |
HIP 41638 |
34.80 |
| 2026-06-11 00:00 |
08:30:03.70 |
+19:50:06.6 |
HIP 41824 |
34.49 |
| 2026-06-11 12:00 |
08:30:21.79 |
+19:48:57.5 |
HIP 41824 |
30.97 |
| 2026-06-12 00:00 |
08:30:39.96 |
+19:47:48.0 |
HIP 41824 |
27.70 |
| 2026-06-12 12:00 |
08:30:58.21 |
+19:46:38.2 |
HIP 41824 |
24.78 |
| 2026-06-13 00:00 |
08:31:16.53 |
+19:45:28.1 |
HIP 41824 |
22.36 |
| 2026-06-13 12:00 |
08:31:34.93 |
+19:44:17.5 |
HIP 41824 |
20.63 |
| 2026-06-14 00:00 |
08:31:53.41 |
+19:43:06.7 |
HIP 41824 |
19.79 |
| 2026-06-14 12:00 |
08:32:11.95 |
+19:41:55.4 |
HIP 41824 |
19.96 |
| 2026-06-15 00:00 |
08:32:30.58 |
+19:40:43.9 |
HIP 41824 |
21.12 |
| 2026-06-15 12:00 |
08:32:49.27 |
+19:39:31.9 |
HIP 41824 |
23.15 |
| 2026-06-16 00:00 |
08:33:08.03 |
+19:38:19.6 |
HIP 41824 |
25.84 |
| 2026-06-16 12:00 |
08:33:26.86 |
+19:37:07.0 |
HIP 42133 |
26.58 |
| 2026-06-17 00:00 |
08:33:45.76 |
+19:35:54.1 |
HIP 42133 |
22.08 |
| 2026-06-17 12:00 |
08:34:04.72 |
+19:34:40.8 |
HIP 42133 |
17.62 |
| 2026-06-18 00:00 |
08:34:23.75 |
+19:33:27.1 |
HIP 42133 |
13.27 |
| 2026-06-18 12:00 |
08:34:42.84 |
+19:32:13.2 |
HIP 42133 |
9.20 |
| 2026-06-19 00:00 |
08:35:02.00 |
+19:30:58.9 |
HIP 42133 |
6.04 |
| 2026-06-19 12:00 |
08:35:21.22 |
+19:29:44.2 |
HIP 42133 |
5.68 |
| 2026-06-20 00:00 |
08:35:40.50 |
+19:28:29.3 |
HIP 42133 |
8.51 |
| 2026-06-20 12:00 |
08:35:59.84 |
+19:27:14.0 |
HIP 42133 |
12.54 |
| 2026-06-21 00:00 |
08:36:19.24 |
+19:25:58.4 |
HIP 42133 |
16.95 |
| 2026-06-21 12:00 |
08:36:38.69 |
+19:24:42.5 |
HIP 42319 |
15.96 |
| 2026-06-22 00:00 |
08:36:58.21 |
+19:23:26.3 |
HIP 42319 |
12.62 |