| Parameter |
Value |
| Designation |
P/2003 T12 (SOHO) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-01-26T10:43:04.114560Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:34Z |
| Obs used |
491 |
| NEO |
Yes |
| M1 |
19.600 |
| K1 |
21.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-05-25.0000000 |
| e |
0.77616614 |
| q (au) |
0.574806 |
| a (au) |
2.568002 |
| i (deg) |
11.475154 |
| Ω (om, deg) |
176.465715 |
| ω (w, deg) |
217.668833 |
| M (ma, deg) |
28.633414 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.124 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.124 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.800 |
| 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 |
| 2016-02-21 |
2016-05-05 |
+25.0682 |
+4.478 |
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 |
13:28:27.99 |
-01:57:46.5 |
HIP 65651 |
15.10 |
| 2026-07-29 12:00 |
13:28:38.25 |
-01:59:17.6 |
HIP 65651 |
18.08 |
| 2026-07-30 00:00 |
13:28:48.67 |
-02:00:49.5 |
HIP 65651 |
21.10 |
| 2026-07-30 12:00 |
13:28:59.24 |
-02:02:22.1 |
HIP 65879 |
20.79 |
| 2026-07-31 00:00 |
13:29:09.95 |
-02:03:55.4 |
HIP 65879 |
19.17 |
| 2026-07-31 12:00 |
13:29:20.82 |
-02:05:29.4 |
HIP 65879 |
17.93 |
| 2026-08-01 00:00 |
13:29:31.84 |
-02:07:04.1 |
HIP 65879 |
17.15 |
| 2026-08-01 12:00 |
13:29:43.01 |
-02:08:39.5 |
HIP 65879 |
16.94 |
| 2026-08-02 00:00 |
13:29:54.33 |
-02:10:15.5 |
HIP 65879 |
17.33 |
| 2026-08-02 12:00 |
13:30:05.79 |
-02:11:52.2 |
HIP 65943 |
16.58 |
| 2026-08-03 00:00 |
13:30:17.40 |
-02:13:29.6 |
HIP 65943 |
13.41 |
| 2026-08-03 12:00 |
13:30:29.16 |
-02:15:07.6 |
HIP 65943 |
10.30 |
| 2026-08-04 00:00 |
13:30:41.06 |
-02:16:46.3 |
HIP 65943 |
7.39 |
| 2026-08-04 12:00 |
13:30:53.10 |
-02:18:25.6 |
HIP 65943 |
5.08 |
| 2026-08-05 00:00 |
13:31:05.29 |
-02:20:05.5 |
HIP 65943 |
4.54 |
| 2026-08-05 12:00 |
13:31:17.62 |
-02:21:46.1 |
HIP 65982 |
6.30 |
| 2026-08-06 00:00 |
13:31:30.09 |
-02:23:27.2 |
HIP 65982 |
5.08 |
| 2026-08-06 12:00 |
13:31:42.71 |
-02:25:09.0 |
HIP 65982 |
6.09 |
| 2026-08-07 00:00 |
13:31:55.46 |
-02:26:51.4 |
HIP 65982 |
8.63 |
| 2026-08-07 12:00 |
13:32:08.35 |
-02:28:34.4 |
HIP 65982 |
11.78 |
| 2026-08-08 00:00 |
13:32:21.38 |
-02:30:18.0 |
HIP 66097 |
10.18 |
| 2026-08-08 12:00 |
13:32:34.55 |
-02:32:02.2 |
HIP 66097 |
8.68 |
| 2026-08-09 00:00 |
13:32:47.86 |
-02:33:47.0 |
HIP 66097 |
8.65 |
| 2026-08-09 12:00 |
13:33:01.30 |
-02:35:32.3 |
HIP 66097 |
10.14 |
| 2026-08-10 00:00 |
13:33:14.88 |
-02:37:18.2 |
HIP 66097 |
12.64 |
| 2026-08-10 12:00 |
13:33:28.59 |
-02:39:04.6 |
HIP 66097 |
15.72 |
| 2026-08-11 00:00 |
13:33:42.44 |
-02:40:51.6 |
HIP 66097 |
19.10 |
| 2026-08-11 12:00 |
13:33:56.41 |
-02:42:39.2 |
HIP 66293 |
20.92 |
| 2026-08-12 00:00 |
13:34:10.53 |
-02:44:27.2 |
HIP 66293 |
18.64 |
| 2026-08-12 12:00 |
13:34:24.77 |
-02:46:15.8 |
HIP 66293 |
16.98 |
| 2026-08-13 00:00 |
13:34:39.14 |
-02:48:05.0 |
HIP 66293 |
16.14 |
| 2026-08-13 12:00 |
13:34:53.64 |
-02:49:54.6 |
HIP 66293 |
16.28 |
| 2026-08-14 00:00 |
13:35:08.27 |
-02:51:44.7 |
HIP 66293 |
17.39 |
| 2026-08-14 12:00 |
13:35:23.02 |
-02:53:35.4 |
HIP 66369 |
14.16 |
| 2026-08-15 00:00 |
13:35:37.90 |
-02:55:26.5 |
HIP 66369 |
10.21 |
| 2026-08-15 12:00 |
13:35:52.91 |
-02:57:18.1 |
HIP 66369 |
6.50 |
| 2026-08-16 00:00 |
13:36:08.04 |
-02:59:10.1 |
HIP 66369 |
3.88 |
| 2026-08-16 12:00 |
13:36:23.30 |
-03:01:02.7 |
HIP 66369 |
4.86 |
| 2026-08-17 00:00 |
13:36:38.68 |
-03:02:55.7 |
HIP 66369 |
8.28 |
| 2026-08-17 12:00 |
13:36:54.18 |
-03:04:49.1 |
HIP 66369 |
12.28 |
| 2026-08-18 00:00 |
13:37:09.79 |
-03:06:43.0 |
HIP 66482 |
11.89 |
| 2026-08-18 12:00 |
13:37:25.53 |
-03:08:37.3 |
HIP 66482 |
7.70 |
| 2026-08-19 00:00 |
13:37:41.39 |
-03:10:32.0 |
HIP 66482 |
3.88 |