| 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) |
| 2026-03-26 00:00 |
05:48:42.55 |
+29:17:04.1 |
HIP 27459 |
9.23 |
| 2026-03-26 12:00 |
05:48:56.25 |
+29:16:52.3 |
HIP 27459 |
8.72 |
| 2026-03-27 00:00 |
05:49:10.16 |
+29:16:40.6 |
HIP 27459 |
9.24 |
| 2026-03-27 12:00 |
05:49:24.30 |
+29:16:28.9 |
HIP 27459 |
10.67 |
| 2026-03-28 00:00 |
05:49:38.65 |
+29:16:17.2 |
HIP 27459 |
12.74 |
| 2026-03-28 12:00 |
05:49:53.21 |
+29:16:05.6 |
HIP 27459 |
15.22 |
| 2026-03-29 00:00 |
05:50:07.99 |
+29:15:54.1 |
HIP 27459 |
17.97 |
| 2026-03-29 12:00 |
05:50:22.98 |
+29:15:42.6 |
HIP 27459 |
20.90 |
| 2026-03-30 00:00 |
05:50:38.19 |
+29:15:31.2 |
HIP 27459 |
23.97 |
| 2026-03-30 12:00 |
05:50:53.60 |
+29:15:19.8 |
HIP 27726 |
23.85 |
| 2026-03-31 00:00 |
05:51:09.22 |
+29:15:08.4 |
HIP 27726 |
21.55 |
| 2026-03-31 12:00 |
05:51:25.05 |
+29:14:57.1 |
HIP 27726 |
19.56 |
| 2026-04-01 00:00 |
05:51:41.08 |
+29:14:45.9 |
HIP 27726 |
17.99 |
| 2026-04-01 12:00 |
05:51:57.32 |
+29:14:34.7 |
HIP 27798 |
15.20 |
| 2026-04-02 00:00 |
05:52:13.76 |
+29:14:23.5 |
HIP 27798 |
12.15 |
| 2026-04-02 12:00 |
05:52:30.40 |
+29:14:12.3 |
HIP 27798 |
9.46 |
| 2026-04-03 00:00 |
05:52:47.24 |
+29:14:01.2 |
HIP 27798 |
7.60 |
| 2026-04-03 12:00 |
05:53:04.29 |
+29:13:50.0 |
HIP 27798 |
7.30 |
| 2026-04-04 00:00 |
05:53:21.53 |
+29:13:39.0 |
HIP 27798 |
8.77 |
| 2026-04-04 12:00 |
05:53:38.96 |
+29:13:27.9 |
HIP 27798 |
11.39 |
| 2026-04-05 00:00 |
05:53:56.59 |
+29:13:16.8 |
HIP 27798 |
14.59 |
| 2026-04-05 12:00 |
05:54:14.42 |
+29:13:05.8 |
HIP 27798 |
18.08 |
| 2026-04-06 00:00 |
05:54:32.44 |
+29:12:54.8 |
HIP 27798 |
21.76 |
| 2026-04-06 12:00 |
05:54:50.65 |
+29:12:43.7 |
HIP 28072 |
20.06 |
| 2026-04-07 00:00 |
05:55:09.06 |
+29:12:32.7 |
HIP 28072 |
16.81 |
| 2026-04-07 12:00 |
05:55:27.65 |
+29:12:21.7 |
HIP 28072 |
13.94 |
| 2026-04-08 00:00 |
05:55:46.43 |
+29:12:10.7 |
HIP 28072 |
11.79 |
| 2026-04-08 12:00 |
05:56:05.40 |
+29:11:59.6 |
HIP 28072 |
10.83 |
| 2026-04-09 00:00 |
05:56:24.56 |
+29:11:48.6 |
HIP 28072 |
11.42 |
| 2026-04-09 12:00 |
05:56:43.90 |
+29:11:37.6 |
HIP 28072 |
13.38 |
| 2026-04-10 00:00 |
05:57:03.42 |
+29:11:26.5 |
HIP 28117 |
16.25 |
| 2026-04-10 12:00 |
05:57:23.13 |
+29:11:15.4 |
HIP 28258 |
17.51 |
| 2026-04-11 00:00 |
05:57:43.02 |
+29:11:04.3 |
HIP 28258 |
15.27 |
| 2026-04-11 12:00 |
05:58:03.08 |
+29:10:53.2 |
HIP 28258 |
14.04 |
| 2026-04-12 00:00 |
05:58:23.33 |
+29:10:42.0 |
HIP 28258 |
14.13 |
| 2026-04-12 12:00 |
05:58:43.76 |
+29:10:30.8 |
HIP 28258 |
15.55 |
| 2026-04-13 00:00 |
05:59:04.36 |
+29:10:19.6 |
HIP 28258 |
18.01 |
| 2026-04-13 12:00 |
05:59:25.14 |
+29:10:08.4 |
HIP 28469 |
18.51 |
| 2026-04-14 00:00 |
05:59:46.10 |
+29:09:57.1 |
HIP 28469 |
14.71 |
| 2026-04-14 12:00 |
06:00:07.23 |
+29:09:45.7 |
HIP 28469 |
11.47 |
| 2026-04-15 00:00 |
06:00:28.53 |
+29:09:34.3 |
HIP 28469 |
9.44 |
| 2026-04-15 12:00 |
06:00:50.00 |
+29:09:22.9 |
HIP 28469 |
9.50 |
| 2026-04-16 00:00 |
06:01:11.64 |
+29:09:11.4 |
HIP 28469 |
11.67 |