P/2003 T12 (SOHO)
| 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) |
| 2026-02-03 00:00 |
14:30:07.94 |
-08:33:18.9 |
HIP 70956 |
11.40 |
| 2026-02-03 12:00 |
14:30:11.90 |
-08:32:37.4 |
HIP 70956 |
10.92 |
| 2026-02-04 00:00 |
14:30:15.65 |
-08:31:54.5 |
HIP 70956 |
10.61 |
| 2026-02-04 12:00 |
14:30:19.17 |
-08:31:10.4 |
HIP 70956 |
10.48 |
| 2026-02-05 00:00 |
14:30:22.47 |
-08:30:25.0 |
HIP 70956 |
10.52 |
| 2026-02-05 12:00 |
14:30:25.54 |
-08:29:38.3 |
HIP 70956 |
10.73 |
| 2026-02-06 00:00 |
14:30:28.38 |
-08:28:50.4 |
HIP 70956 |
11.08 |
| 2026-02-06 12:00 |
14:30:31.00 |
-08:28:01.2 |
HIP 70956 |
11.56 |
| 2026-02-07 00:00 |
14:30:33.39 |
-08:27:10.6 |
HIP 70956 |
12.15 |
| 2026-02-07 12:00 |
14:30:35.54 |
-08:26:18.8 |
HIP 70956 |
12.84 |
| 2026-02-08 00:00 |
14:30:37.47 |
-08:25:25.7 |
HIP 70956 |
13.59 |
| 2026-02-08 12:00 |
14:30:39.17 |
-08:24:31.3 |
HIP 70956 |
14.41 |
| 2026-02-09 00:00 |
14:30:40.63 |
-08:23:35.7 |
HIP 70956 |
15.27 |
| 2026-02-09 12:00 |
14:30:41.86 |
-08:22:38.7 |
HIP 70956 |
16.18 |
| 2026-02-10 00:00 |
14:30:42.85 |
-08:21:40.4 |
HIP 70956 |
17.13 |
| 2026-02-10 12:00 |
14:30:43.61 |
-08:20:40.9 |
HIP 70956 |
18.10 |
| 2026-02-11 00:00 |
14:30:44.13 |
-08:19:40.0 |
HIP 70956 |
19.11 |
| 2026-02-11 12:00 |
14:30:44.41 |
-08:18:37.8 |
HIP 70956 |
20.14 |
| 2026-02-12 00:00 |
14:30:44.46 |
-08:17:34.4 |
HIP 70956 |
21.20 |
| 2026-02-12 12:00 |
14:30:44.27 |
-08:16:29.6 |
HIP 70956 |
22.28 |
| 2026-02-13 00:00 |
14:30:43.83 |
-08:15:23.6 |
HIP 70956 |
23.38 |
| 2026-02-13 12:00 |
14:30:43.16 |
-08:14:16.2 |
HIP 70956 |
24.51 |
| 2026-02-14 00:00 |
14:30:42.25 |
-08:13:07.6 |
HIP 70956 |
25.66 |
| 2026-02-14 12:00 |
14:30:41.09 |
-08:11:57.7 |
HIP 70956 |
26.85 |
| 2026-02-15 00:00 |
14:30:39.69 |
-08:10:46.5 |
HIP 70956 |
28.05 |
| 2026-02-15 12:00 |
14:30:38.05 |
-08:09:33.9 |
HIP 70956 |
29.29 |
| 2026-02-16 00:00 |
14:30:36.16 |
-08:08:20.1 |
HIP 70956 |
30.56 |
| 2026-02-16 12:00 |
14:30:34.04 |
-08:07:05.0 |
HIP 70956 |
31.86 |
| 2026-02-17 00:00 |
14:30:31.66 |
-08:05:48.6 |
HIP 70956 |
33.20 |
| 2026-02-17 12:00 |
14:30:29.04 |
-08:04:31.0 |
HIP 70956 |
34.56 |
| 2026-02-18 00:00 |
14:30:26.18 |
-08:03:12.0 |
HIP 70766 |
34.23 |
| 2026-02-18 12:00 |
14:30:23.06 |
-08:01:51.8 |
HIP 70766 |
32.99 |
| 2026-02-19 00:00 |
14:30:19.71 |
-08:00:30.3 |
HIP 70766 |
31.70 |
| 2026-02-19 12:00 |
14:30:16.10 |
-07:59:07.5 |
HIP 70766 |
30.38 |
| 2026-02-20 00:00 |
14:30:12.25 |
-07:57:43.4 |
HIP 70766 |
29.03 |
| 2026-02-20 12:00 |
14:30:08.15 |
-07:56:18.1 |
HIP 70766 |
27.66 |
| 2026-02-21 00:00 |
14:30:03.81 |
-07:54:51.5 |
HIP 70766 |
26.26 |
| 2026-02-21 12:00 |
14:29:59.22 |
-07:53:23.7 |
HIP 70766 |
24.85 |
| 2026-02-22 00:00 |
14:29:54.38 |
-07:51:54.6 |
HIP 70766 |
23.44 |
| 2026-02-22 12:00 |
14:29:49.29 |
-07:50:24.2 |
HIP 70766 |
22.04 |
| 2026-02-23 00:00 |
14:29:43.95 |
-07:48:52.6 |
HIP 70766 |
20.67 |
| 2026-02-23 12:00 |
14:29:38.37 |
-07:47:19.8 |
HIP 70766 |
19.35 |
| 2026-02-24 00:00 |
14:29:32.54 |
-07:45:45.7 |
HIP 70766 |
18.13 |