| Parameter |
Value |
| Designation |
C/2004 T3 (Siding Spring) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2003-04-15T07:34:17.973120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:43Z |
| Obs used |
106 |
| NEO |
- |
| M1 |
6.300 |
| K1 |
7.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2005-02-13.0000000 |
| e |
0.99848905 |
| q (au) |
8.864365 |
| a (au) |
5866.764568 |
| i (deg) |
71.964320 |
| Ω (om, deg) |
50.354596 |
| ω (w, deg) |
259.686905 |
| M (ma, deg) |
0.001469 |
Magnitude
Scatter + Global Linear
$$
M_a = (-1.455 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
-1.455 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
03:11:39.26 |
+39:31:00.9 |
HIP 14817 |
7.07 |
| 2026-03-26 12:00 |
03:11:41.93 |
+39:31:01.7 |
HIP 14817 |
7.38 |
| 2026-03-27 00:00 |
03:11:44.61 |
+39:31:02.7 |
HIP 14817 |
7.71 |
| 2026-03-27 12:00 |
03:11:47.32 |
+39:31:03.8 |
HIP 14817 |
8.06 |
| 2026-03-28 00:00 |
03:11:50.05 |
+39:31:05.1 |
HIP 14817 |
8.43 |
| 2026-03-28 12:00 |
03:11:52.80 |
+39:31:06.6 |
HIP 14817 |
8.82 |
| 2026-03-29 00:00 |
03:11:55.58 |
+39:31:08.2 |
HIP 14817 |
9.22 |
| 2026-03-29 12:00 |
03:11:58.37 |
+39:31:10.0 |
HIP 14817 |
9.64 |
| 2026-03-30 00:00 |
03:12:01.18 |
+39:31:12.0 |
HIP 14817 |
10.07 |
| 2026-03-30 12:00 |
03:12:04.02 |
+39:31:14.1 |
HIP 14817 |
10.51 |
| 2026-03-31 00:00 |
03:12:06.87 |
+39:31:16.4 |
HIP 14817 |
10.97 |
| 2026-03-31 12:00 |
03:12:09.74 |
+39:31:18.8 |
HIP 14817 |
11.43 |
| 2026-04-01 00:00 |
03:12:12.64 |
+39:31:21.5 |
HIP 14817 |
11.91 |
| 2026-04-01 12:00 |
03:12:15.55 |
+39:31:24.3 |
HIP 14817 |
12.39 |
| 2026-04-02 00:00 |
03:12:18.48 |
+39:31:27.2 |
HIP 14817 |
12.89 |
| 2026-04-02 12:00 |
03:12:21.43 |
+39:31:30.3 |
HIP 14817 |
13.39 |
| 2026-04-03 00:00 |
03:12:24.41 |
+39:31:33.6 |
HIP 14817 |
13.90 |
| 2026-04-03 12:00 |
03:12:27.39 |
+39:31:37.1 |
HIP 14817 |
14.41 |
| 2026-04-04 00:00 |
03:12:30.40 |
+39:31:40.7 |
HIP 14817 |
14.94 |
| 2026-04-04 12:00 |
03:12:33.43 |
+39:31:44.5 |
HIP 14817 |
15.47 |
| 2026-04-05 00:00 |
03:12:36.47 |
+39:31:48.5 |
HIP 14817 |
16.00 |
| 2026-04-05 12:00 |
03:12:39.53 |
+39:31:52.6 |
HIP 14817 |
16.54 |
| 2026-04-06 00:00 |
03:12:42.61 |
+39:31:56.9 |
HIP 14817 |
17.09 |
| 2026-04-06 12:00 |
03:12:45.71 |
+39:32:01.3 |
HIP 14817 |
17.65 |
| 2026-04-07 00:00 |
03:12:48.83 |
+39:32:05.9 |
HIP 14817 |
18.21 |
| 2026-04-07 12:00 |
03:12:51.96 |
+39:32:10.7 |
HIP 14817 |
18.77 |
| 2026-04-08 00:00 |
03:12:55.11 |
+39:32:15.7 |
HIP 14817 |
19.34 |
| 2026-04-08 12:00 |
03:12:58.27 |
+39:32:20.8 |
HIP 14817 |
19.92 |
| 2026-04-09 00:00 |
03:13:01.45 |
+39:32:26.0 |
HIP 14817 |
20.50 |
| 2026-04-09 12:00 |
03:13:04.65 |
+39:32:31.5 |
HIP 14817 |
21.08 |
| 2026-04-10 00:00 |
03:13:07.87 |
+39:32:37.1 |
HIP 14817 |
21.67 |
| 2026-04-10 12:00 |
03:13:11.09 |
+39:32:42.8 |
HIP 14817 |
22.27 |
| 2026-04-11 00:00 |
03:13:14.34 |
+39:32:48.8 |
HIP 14817 |
22.86 |
| 2026-04-11 12:00 |
03:13:17.60 |
+39:32:54.9 |
HIP 14817 |
23.47 |
| 2026-04-12 00:00 |
03:13:20.88 |
+39:33:01.1 |
HIP 14817 |
24.07 |
| 2026-04-12 12:00 |
03:13:24.17 |
+39:33:07.5 |
HIP 15017 |
24.38 |
| 2026-04-13 00:00 |
03:13:27.47 |
+39:33:14.1 |
HIP 15017 |
24.45 |
| 2026-04-13 12:00 |
03:13:30.79 |
+39:33:20.9 |
HIP 15017 |
24.53 |
| 2026-04-14 00:00 |
03:13:34.13 |
+39:33:27.8 |
HIP 15017 |
24.64 |
| 2026-04-14 12:00 |
03:13:37.47 |
+39:33:34.9 |
HIP 15094 |
24.61 |
| 2026-04-15 00:00 |
03:13:40.84 |
+39:33:42.1 |
HIP 15094 |
24.18 |
| 2026-04-15 12:00 |
03:13:44.21 |
+39:33:49.5 |
HIP 15094 |
23.75 |
| 2026-04-16 00:00 |
03:13:47.60 |
+39:33:57.0 |
HIP 15094 |
23.33 |