| Parameter |
Value |
| Designation |
9P/Tempel 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2016-08-02T13:41:50.605440Z |
| Orbit solution date (soln_date, UTC) |
2025-12-29T09:30:51Z |
| Obs used |
3283 |
| NEO |
- |
| M1 |
12.900 |
| K1 |
9.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-03-23.0000000 |
| e |
0.50970283 |
| q (au) |
1.542540 |
| a (au) |
3.146134 |
| i (deg) |
10.473428 |
| Ω (om, deg) |
68.753575 |
| ω (w, deg) |
179.197275 |
| M (ma, deg) |
336.585444 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.310 + 3.470\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.310 |
| n |
3.470 |
| gf |
0.940 |
| gb |
-0.756 |
| k |
0.852 |
| δ90 |
2.245 |
| 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) |
| 2026-05-12 00:00 |
06:23:20.27 |
+28:56:33.8 |
HIP 30388 |
11.23 |
| 2026-05-12 12:00 |
06:23:49.20 |
+28:56:14.6 |
HIP 30388 |
12.31 |
| 2026-05-13 00:00 |
06:24:18.24 |
+28:55:55.2 |
HIP 30388 |
16.06 |
| 2026-05-13 12:00 |
06:24:47.39 |
+28:55:35.5 |
HIP 30388 |
21.13 |
| 2026-05-14 00:00 |
06:25:16.65 |
+28:55:15.6 |
HIP 30388 |
26.79 |
| 2026-05-14 12:00 |
06:25:46.02 |
+28:54:55.4 |
HIP 30388 |
32.75 |
| 2026-05-15 00:00 |
06:26:15.49 |
+28:54:35.0 |
HIP 30779 |
30.77 |
| 2026-05-15 12:00 |
06:26:45.07 |
+28:54:14.4 |
HIP 30779 |
26.44 |
| 2026-05-16 00:00 |
06:27:14.75 |
+28:53:53.5 |
HIP 30779 |
23.14 |
| 2026-05-16 12:00 |
06:27:44.54 |
+28:53:32.4 |
HIP 30779 |
21.35 |
| 2026-05-17 00:00 |
06:28:14.42 |
+28:53:11.0 |
HIP 30943 |
19.68 |
| 2026-05-17 12:00 |
06:28:44.41 |
+28:52:49.3 |
HIP 30943 |
13.46 |
| 2026-05-18 00:00 |
06:29:14.50 |
+28:52:27.4 |
HIP 30943 |
7.84 |
| 2026-05-18 12:00 |
06:29:44.69 |
+28:52:05.3 |
HIP 30943 |
5.37 |
| 2026-05-19 00:00 |
06:30:14.98 |
+28:51:42.8 |
HIP 30943 |
9.17 |
| 2026-05-19 12:00 |
06:30:45.36 |
+28:51:20.1 |
HIP 30943 |
15.11 |
| 2026-05-20 00:00 |
06:31:15.84 |
+28:50:57.2 |
HIP 31117 |
10.55 |
| 2026-05-20 12:00 |
06:31:46.42 |
+28:50:33.9 |
HIP 31117 |
8.66 |
| 2026-05-21 00:00 |
06:32:17.09 |
+28:50:10.4 |
HIP 31117 |
11.35 |
| 2026-05-21 12:00 |
06:32:47.85 |
+28:49:46.7 |
HIP 31117 |
16.55 |
| 2026-05-22 00:00 |
06:33:18.70 |
+28:49:22.6 |
HIP 31202 |
21.53 |
| 2026-05-22 12:00 |
06:33:49.64 |
+28:48:58.3 |
HIP 31202 |
24.94 |
| 2026-05-23 00:00 |
06:34:20.67 |
+28:48:33.7 |
HIP 31444 |
25.08 |
| 2026-05-23 12:00 |
06:34:51.79 |
+28:48:08.8 |
HIP 31544 |
22.15 |
| 2026-05-24 00:00 |
06:35:23.00 |
+28:47:43.6 |
HIP 31544 |
17.66 |
| 2026-05-24 12:00 |
06:35:54.30 |
+28:47:18.1 |
HIP 31544 |
15.07 |
| 2026-05-25 00:00 |
06:36:25.68 |
+28:46:52.4 |
HIP 31544 |
15.38 |
| 2026-05-25 12:00 |
06:36:57.14 |
+28:46:26.3 |
HIP 31544 |
18.47 |
| 2026-05-26 00:00 |
06:37:28.69 |
+28:46:00.0 |
HIP 31767 |
16.29 |
| 2026-05-26 12:00 |
06:38:00.32 |
+28:45:33.3 |
HIP 31767 |
9.83 |
| 2026-05-27 00:00 |
06:38:32.04 |
+28:45:06.4 |
HIP 31767 |
4.93 |
| 2026-05-27 12:00 |
06:39:03.83 |
+28:44:39.2 |
HIP 31767 |
7.02 |
| 2026-05-28 00:00 |
06:39:35.71 |
+28:44:11.6 |
HIP 31767 |
13.13 |
| 2026-05-28 12:00 |
06:40:07.67 |
+28:43:43.8 |
HIP 31767 |
19.85 |
| 2026-05-29 00:00 |
06:40:39.70 |
+28:43:15.7 |
HIP 31856 |
25.42 |
| 2026-05-29 12:00 |
06:41:11.82 |
+28:42:47.2 |
HIP 31856 |
29.61 |
| 2026-05-30 00:00 |
06:41:44.01 |
+28:42:18.4 |
HIP 32019 |
30.93 |
| 2026-05-30 12:00 |
06:42:16.28 |
+28:41:49.4 |
HIP 32225 |
25.24 |
| 2026-05-31 00:00 |
06:42:48.62 |
+28:41:20.0 |
HIP 32225 |
20.37 |
| 2026-05-31 12:00 |
06:43:21.04 |
+28:40:50.3 |
HIP 32225 |
17.15 |
| 2026-06-01 00:00 |
06:43:53.53 |
+28:40:20.3 |
HIP 32225 |
16.58 |
| 2026-06-01 12:00 |
06:44:26.10 |
+28:39:49.9 |
HIP 32279 |
17.73 |
| 2026-06-02 00:00 |
06:44:58.74 |
+28:39:19.3 |
HIP 32279 |
19.13 |