| 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) |
| 2026-03-26 00:00 |
14:16:31.19 |
-05:38:42.5 |
HIP 69775 |
4.54 |
| 2026-03-26 12:00 |
14:16:11.74 |
-05:36:09.7 |
HIP 69775 |
9.70 |
| 2026-03-27 00:00 |
14:15:52.12 |
-05:33:36.4 |
HIP 69775 |
15.13 |
| 2026-03-27 12:00 |
14:15:32.33 |
-05:31:02.6 |
HIP 69586 |
17.91 |
| 2026-03-28 00:00 |
14:15:12.38 |
-05:28:28.3 |
HIP 69586 |
12.50 |
| 2026-03-28 12:00 |
14:14:52.26 |
-05:25:53.6 |
HIP 69586 |
7.35 |
| 2026-03-29 00:00 |
14:14:32.00 |
-05:23:18.5 |
HIP 69586 |
3.90 |
| 2026-03-29 12:00 |
14:14:11.57 |
-05:20:43.0 |
HIP 69586 |
6.41 |
| 2026-03-30 00:00 |
14:13:51.00 |
-05:18:07.0 |
HIP 69586 |
11.53 |
| 2026-03-30 12:00 |
14:13:30.27 |
-05:15:30.7 |
HIP 69586 |
17.09 |
| 2026-03-31 00:00 |
14:13:09.41 |
-05:12:54.1 |
HIP 69586 |
22.80 |
| 2026-03-31 12:00 |
14:12:48.39 |
-05:10:17.1 |
HIP 69586 |
28.59 |
| 2026-04-01 00:00 |
14:12:27.24 |
-05:07:39.8 |
HIP 69586 |
34.43 |
| 2026-04-01 12:00 |
14:12:05.96 |
-05:05:02.2 |
HIP 69242 |
32.51 |
| 2026-04-02 00:00 |
14:11:44.53 |
-05:02:24.4 |
HIP 69242 |
30.97 |
| 2026-04-02 12:00 |
14:11:22.98 |
-04:59:46.3 |
HIP 69242 |
30.52 |
| 2026-04-03 00:00 |
14:11:01.30 |
-04:57:07.9 |
HIP 69242 |
31.22 |
| 2026-04-03 12:00 |
14:10:39.50 |
-04:54:29.4 |
HIP 69242 |
33.03 |
| 2026-04-04 00:00 |
14:10:17.57 |
-04:51:50.7 |
HIP 69052 |
34.25 |
| 2026-04-04 12:00 |
14:09:55.53 |
-04:49:11.8 |
HIP 69052 |
28.37 |
| 2026-04-05 00:00 |
14:09:33.37 |
-04:46:32.8 |
HIP 69052 |
22.57 |
| 2026-04-05 12:00 |
14:09:11.10 |
-04:43:53.7 |
HIP 69052 |
16.96 |
| 2026-04-06 00:00 |
14:08:48.72 |
-04:41:14.4 |
HIP 69052 |
11.89 |
| 2026-04-06 12:00 |
14:08:26.24 |
-04:38:35.1 |
HIP 69052 |
8.41 |
| 2026-04-07 00:00 |
14:08:03.65 |
-04:35:55.8 |
HIP 69052 |
8.78 |
| 2026-04-07 12:00 |
14:07:40.97 |
-04:33:16.4 |
HIP 69052 |
12.70 |
| 2026-04-08 00:00 |
14:07:18.19 |
-04:30:37.0 |
HIP 69052 |
17.99 |
| 2026-04-08 12:00 |
14:06:55.33 |
-04:27:57.7 |
HIP 68899 |
19.71 |
| 2026-04-09 00:00 |
14:06:32.37 |
-04:25:18.3 |
HIP 68899 |
15.61 |
| 2026-04-09 12:00 |
14:06:09.33 |
-04:22:39.1 |
HIP 68899 |
13.36 |
| 2026-04-10 00:00 |
14:05:46.21 |
-04:19:59.9 |
HIP 68899 |
13.92 |
| 2026-04-10 12:00 |
14:05:23.01 |
-04:17:20.8 |
HIP 68899 |
17.04 |
| 2026-04-11 00:00 |
14:04:59.74 |
-04:14:41.9 |
HIP 68716 |
21.08 |
| 2026-04-11 12:00 |
14:04:36.40 |
-04:12:03.1 |
HIP 68716 |
15.35 |
| 2026-04-12 00:00 |
14:04:12.99 |
-04:09:24.6 |
HIP 68716 |
10.44 |
| 2026-04-12 12:00 |
14:03:49.52 |
-04:06:46.2 |
HIP 68716 |
8.02 |
| 2026-04-13 00:00 |
14:03:25.99 |
-04:04:08.1 |
HIP 68716 |
10.12 |
| 2026-04-13 12:00 |
14:03:02.41 |
-04:01:30.2 |
HIP 68716 |
14.96 |
| 2026-04-14 00:00 |
14:02:38.78 |
-03:58:52.6 |
HIP 68716 |
20.71 |
| 2026-04-14 12:00 |
14:02:15.10 |
-03:56:15.3 |
HIP 68716 |
26.79 |
| 2026-04-15 00:00 |
14:01:51.38 |
-03:53:38.3 |
HIP 68716 |
33.02 |
| 2026-04-15 12:00 |
14:01:27.61 |
-03:51:01.8 |
HIP 68380 |
30.45 |
| 2026-04-16 00:00 |
14:01:03.82 |
-03:48:25.5 |
HIP 68380 |
24.17 |