| Parameter |
Value |
| Designation |
P/2007 S1 (Zhao) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2007-12-06T20:05:23.029440Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:12Z |
| Obs used |
78 |
| NEO |
- |
| M1 |
13.500 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2007-09-29.0000000 |
| e |
0.34338434 |
| q (au) |
2.494391 |
| a (au) |
3.798860 |
| i (deg) |
5.973039 |
| Ω (om, deg) |
141.618584 |
| ω (w, deg) |
245.425020 |
| M (ma, deg) |
350.836814 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.850 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.850 |
| n |
6.000 |
| gf |
0.876 |
| gb |
-0.879 |
| k |
1.000 |
| δ90 |
3.511 |
| 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) |
| 2026-09-20 00:00 |
13:45:32.77 |
-05:44:08.3 |
HIP 67083 |
18.30 |
| 2026-09-20 12:00 |
13:45:55.58 |
-05:46:26.6 |
HIP 67083 |
19.99 |
| 2026-09-21 00:00 |
13:46:18.44 |
-05:48:45.0 |
HIP 67083 |
23.23 |
| 2026-09-21 12:00 |
13:46:41.36 |
-05:51:03.4 |
HIP 67285 |
20.05 |
| 2026-09-22 00:00 |
13:47:04.34 |
-05:53:21.9 |
HIP 67285 |
15.53 |
| 2026-09-22 12:00 |
13:47:27.37 |
-05:55:40.3 |
HIP 67285 |
12.49 |
| 2026-09-23 00:00 |
13:47:50.45 |
-05:57:58.8 |
HIP 67285 |
12.14 |
| 2026-09-23 12:00 |
13:48:13.59 |
-06:00:17.4 |
HIP 67285 |
14.68 |
| 2026-09-24 00:00 |
13:48:36.78 |
-06:02:35.9 |
HIP 67285 |
19.00 |
| 2026-09-24 12:00 |
13:49:00.02 |
-06:04:54.4 |
HIP 67285 |
24.17 |
| 2026-09-25 00:00 |
13:49:23.32 |
-06:07:13.0 |
HIP 67285 |
29.76 |
| 2026-09-25 12:00 |
13:49:46.67 |
-06:09:31.5 |
HIP 67622 |
32.25 |
| 2026-09-26 00:00 |
13:50:10.07 |
-06:11:50.1 |
HIP 67622 |
30.08 |
| 2026-09-26 12:00 |
13:50:33.52 |
-06:14:08.6 |
HIP 67622 |
29.11 |
| 2026-09-27 00:00 |
13:50:57.01 |
-06:16:27.1 |
HIP 67622 |
29.47 |
| 2026-09-27 12:00 |
13:51:20.56 |
-06:18:45.6 |
HIP 67765 |
25.54 |
| 2026-09-28 00:00 |
13:51:44.16 |
-06:21:04.1 |
HIP 67765 |
19.25 |
| 2026-09-28 12:00 |
13:52:07.81 |
-06:23:22.6 |
HIP 67765 |
12.96 |
| 2026-09-29 00:00 |
13:52:31.50 |
-06:25:41.0 |
HIP 67765 |
6.70 |
| 2026-09-29 12:00 |
13:52:55.25 |
-06:27:59.5 |
HIP 67765 |
1.35 |
| 2026-09-30 00:00 |
13:53:19.04 |
-06:30:17.8 |
HIP 67765 |
6.25 |
| 2026-09-30 12:00 |
13:53:42.87 |
-06:32:36.2 |
HIP 67765 |
12.54 |
| 2026-10-01 00:00 |
13:54:06.76 |
-06:34:54.5 |
HIP 67765 |
18.88 |
| 2026-10-01 12:00 |
13:54:30.68 |
-06:37:12.7 |
HIP 67765 |
25.24 |
| 2026-10-02 00:00 |
13:54:54.66 |
-06:39:30.9 |
HIP 68063 |
21.04 |
| 2026-10-02 12:00 |
13:55:18.68 |
-06:41:49.1 |
HIP 68063 |
17.51 |
| 2026-10-03 00:00 |
13:55:42.74 |
-06:44:07.1 |
HIP 68063 |
15.89 |
| 2026-10-03 12:00 |
13:56:06.85 |
-06:46:25.2 |
HIP 68063 |
16.74 |
| 2026-10-04 00:00 |
13:56:31.00 |
-06:48:43.1 |
HIP 68063 |
19.76 |
| 2026-10-04 12:00 |
13:56:55.19 |
-06:51:01.0 |
HIP 68254 |
21.98 |
| 2026-10-05 00:00 |
13:57:19.42 |
-06:53:18.8 |
HIP 68254 |
15.97 |
| 2026-10-05 12:00 |
13:57:43.70 |
-06:55:36.5 |
HIP 68254 |
10.46 |
| 2026-10-06 00:00 |
13:58:08.02 |
-06:57:54.2 |
HIP 68254 |
6.86 |
| 2026-10-06 12:00 |
13:58:32.38 |
-07:00:11.7 |
HIP 68254 |
8.24 |
| 2026-10-07 00:00 |
13:58:56.78 |
-07:02:29.1 |
HIP 68309 |
7.03 |
| 2026-10-07 12:00 |
13:59:21.21 |
-07:04:46.5 |
HIP 68309 |
10.67 |
| 2026-10-08 00:00 |
13:59:45.69 |
-07:07:03.7 |
HIP 68309 |
16.21 |
| 2026-10-08 12:00 |
14:00:10.20 |
-07:09:20.8 |
HIP 68471 |
13.99 |
| 2026-10-09 00:00 |
14:00:34.75 |
-07:11:37.9 |
HIP 68471 |
9.01 |
| 2026-10-09 12:00 |
14:00:59.34 |
-07:13:54.7 |
HIP 68471 |
7.17 |
| 2026-10-10 00:00 |
14:01:23.96 |
-07:16:11.5 |
HIP 68471 |
10.31 |
| 2026-10-10 12:00 |
14:01:48.62 |
-07:18:28.1 |
HIP 68471 |
15.70 |
| 2026-10-11 00:00 |
14:02:13.32 |
-07:20:44.6 |
HIP 68661 |
19.93 |