P/2007 S1 (Zhao)
| 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
$$
M_a = (10.896 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.896 |
| n |
6.000 |
| gf |
0.870 |
| gb |
-0.881 |
| k |
1.000 |
| δ90 |
2.896 |
| 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) |
| 2026-02-03 00:00 |
13:47:41.27 |
-05:28:17.0 |
HIP 67323 |
8.48 |
| 2026-02-03 12:00 |
13:47:43.65 |
-05:27:48.3 |
HIP 67323 |
8.68 |
| 2026-02-04 00:00 |
13:47:45.83 |
-05:27:18.4 |
HIP 67323 |
8.97 |
| 2026-02-04 12:00 |
13:47:47.82 |
-05:26:47.3 |
HIP 67323 |
9.34 |
| 2026-02-05 00:00 |
13:47:49.62 |
-05:26:15.2 |
HIP 67323 |
9.77 |
| 2026-02-05 12:00 |
13:47:51.23 |
-05:25:41.9 |
HIP 67370 |
10.06 |
| 2026-02-06 00:00 |
13:47:52.64 |
-05:25:07.4 |
HIP 67370 |
9.74 |
| 2026-02-06 12:00 |
13:47:53.85 |
-05:24:31.9 |
HIP 67370 |
9.51 |
| 2026-02-07 00:00 |
13:47:54.87 |
-05:23:55.2 |
HIP 67370 |
9.37 |
| 2026-02-07 12:00 |
13:47:55.70 |
-05:23:17.4 |
HIP 67370 |
9.33 |
| 2026-02-08 00:00 |
13:47:56.32 |
-05:22:38.4 |
HIP 67370 |
9.39 |
| 2026-02-08 12:00 |
13:47:56.76 |
-05:21:58.3 |
HIP 67370 |
9.55 |
| 2026-02-09 00:00 |
13:47:56.99 |
-05:21:17.1 |
HIP 67370 |
9.81 |
| 2026-02-09 12:00 |
13:47:57.02 |
-05:20:34.7 |
HIP 67370 |
10.15 |
| 2026-02-10 00:00 |
13:47:56.86 |
-05:19:51.2 |
HIP 67370 |
10.59 |
| 2026-02-10 12:00 |
13:47:56.50 |
-05:19:06.6 |
HIP 67370 |
11.10 |
| 2026-02-11 00:00 |
13:47:55.94 |
-05:18:20.9 |
HIP 67370 |
11.69 |
| 2026-02-11 12:00 |
13:47:55.19 |
-05:17:34.1 |
HIP 67370 |
12.35 |
| 2026-02-12 00:00 |
13:47:54.23 |
-05:16:46.1 |
HIP 67370 |
13.08 |
| 2026-02-12 12:00 |
13:47:53.07 |
-05:15:57.1 |
HIP 67370 |
13.86 |
| 2026-02-13 00:00 |
13:47:51.72 |
-05:15:06.9 |
HIP 67370 |
14.70 |
| 2026-02-13 12:00 |
13:47:50.17 |
-05:14:15.6 |
HIP 67370 |
15.60 |
| 2026-02-14 00:00 |
13:47:48.41 |
-05:13:23.2 |
HIP 67370 |
16.54 |
| 2026-02-14 12:00 |
13:47:46.46 |
-05:12:29.7 |
HIP 67370 |
17.54 |
| 2026-02-15 00:00 |
13:47:44.31 |
-05:11:35.1 |
HIP 67370 |
18.58 |
| 2026-02-15 12:00 |
13:47:41.96 |
-05:10:39.4 |
HIP 67370 |
19.67 |
| 2026-02-16 00:00 |
13:47:39.41 |
-05:09:42.6 |
HIP 67370 |
20.80 |
| 2026-02-16 12:00 |
13:47:36.66 |
-05:08:44.8 |
HIP 67370 |
21.98 |
| 2026-02-17 00:00 |
13:47:33.71 |
-05:07:45.8 |
HIP 67370 |
23.21 |
| 2026-02-17 12:00 |
13:47:30.57 |
-05:06:45.8 |
HIP 67209 |
22.76 |
| 2026-02-18 00:00 |
13:47:27.22 |
-05:05:44.7 |
HIP 67209 |
21.48 |
| 2026-02-18 12:00 |
13:47:23.68 |
-05:04:42.6 |
HIP 67209 |
20.15 |
| 2026-02-19 00:00 |
13:47:19.94 |
-05:03:39.3 |
HIP 67209 |
18.77 |
| 2026-02-19 12:00 |
13:47:16.00 |
-05:02:35.1 |
HIP 67209 |
17.35 |
| 2026-02-20 00:00 |
13:47:11.86 |
-05:01:29.8 |
HIP 67209 |
15.89 |
| 2026-02-20 12:00 |
13:47:07.53 |
-05:00:23.4 |
HIP 67209 |
14.38 |
| 2026-02-21 00:00 |
13:47:03.00 |
-04:59:16.1 |
HIP 67209 |
12.82 |
| 2026-02-21 12:00 |
13:46:58.27 |
-04:58:07.7 |
HIP 67209 |
11.23 |
| 2026-02-22 00:00 |
13:46:53.35 |
-04:56:58.3 |
HIP 67209 |
9.60 |
| 2026-02-22 12:00 |
13:46:48.24 |
-04:55:47.8 |
HIP 67209 |
7.94 |
| 2026-02-23 00:00 |
13:46:42.93 |
-04:54:36.4 |
HIP 67209 |
6.28 |
| 2026-02-23 12:00 |
13:46:37.42 |
-04:53:24.0 |
HIP 67209 |
4.64 |
| 2026-02-24 00:00 |
13:46:31.73 |
-04:52:10.6 |
HIP 67209 |
3.17 |