| Parameter |
Value |
| Designation |
447P/Sheppard-Tholen |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-08-01T11:34:43.152960Z |
| Orbit solution date (soln_date, UTC) |
2022-12-23T17:43:31Z |
| Obs used |
75 |
| NEO |
- |
| M1 |
7.600 |
| K1 |
16.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2008-10-09T08:24:27.648000Z |
| Discovery magnitude (MPC) |
22.60 V |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-05-24.0000000 |
| e |
0.18072317 |
| q (au) |
4.665883 |
| a (au) |
5.695124 |
| i (deg) |
7.414149 |
| Ω (om, deg) |
302.834446 |
| ω (w, deg) |
95.085999 |
| M (ma, deg) |
222.542292 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.659 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.659 |
| 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) |
| 2026-09-20 00:00 |
11:12:32.96 |
+00:09:09.0 |
HIP 54803 |
10.69 |
| 2026-09-20 12:00 |
11:12:53.54 |
+00:06:45.3 |
HIP 54803 |
8.68 |
| 2026-09-21 00:00 |
11:13:14.10 |
+00:04:21.5 |
HIP 54803 |
10.05 |
| 2026-09-21 12:00 |
11:13:34.64 |
+00:01:57.7 |
HIP 54849 |
6.71 |
| 2026-09-22 00:00 |
11:13:55.17 |
-00:00:26.3 |
HIP 54849 |
4.44 |
| 2026-09-22 12:00 |
11:14:15.67 |
-00:02:50.2 |
HIP 54849 |
7.64 |
| 2026-09-23 00:00 |
11:14:36.15 |
-00:05:14.2 |
HIP 54849 |
12.69 |
| 2026-09-23 12:00 |
11:14:56.62 |
-00:07:38.3 |
HIP 55023 |
14.48 |
| 2026-09-24 00:00 |
11:15:17.06 |
-00:10:02.4 |
HIP 55023 |
10.11 |
| 2026-09-24 12:00 |
11:15:37.47 |
-00:12:26.5 |
HIP 55023 |
7.65 |
| 2026-09-25 00:00 |
11:15:57.87 |
-00:14:50.7 |
HIP 55023 |
8.87 |
| 2026-09-25 12:00 |
11:16:18.24 |
-00:17:14.9 |
HIP 55023 |
12.73 |
| 2026-09-26 00:00 |
11:16:38.58 |
-00:19:39.1 |
HIP 55023 |
17.58 |
| 2026-09-26 12:00 |
11:16:58.90 |
-00:22:03.4 |
HIP 55023 |
22.78 |
| 2026-09-27 00:00 |
11:17:19.20 |
-00:24:27.7 |
HIP 55023 |
28.14 |
| 2026-09-27 12:00 |
11:17:39.47 |
-00:26:52.0 |
HIP 55304 |
32.36 |
| 2026-09-28 00:00 |
11:17:59.72 |
-00:29:16.3 |
HIP 55304 |
29.44 |
| 2026-09-28 12:00 |
11:18:19.94 |
-00:31:40.6 |
HIP 55304 |
27.37 |
| 2026-09-29 00:00 |
11:18:40.13 |
-00:34:05.0 |
HIP 55304 |
26.35 |
| 2026-09-29 12:00 |
11:19:00.30 |
-00:36:29.3 |
HIP 55304 |
26.50 |
| 2026-09-30 00:00 |
11:19:20.43 |
-00:38:53.7 |
HIP 55438 |
27.18 |
| 2026-09-30 12:00 |
11:19:40.54 |
-00:41:18.0 |
HIP 55438 |
22.40 |
| 2026-10-01 00:00 |
11:20:00.62 |
-00:43:42.4 |
HIP 55438 |
18.09 |
| 2026-10-01 12:00 |
11:20:20.67 |
-00:46:06.7 |
HIP 55438 |
14.66 |
| 2026-10-02 00:00 |
11:20:40.69 |
-00:48:31.1 |
HIP 55438 |
12.83 |
| 2026-10-02 12:00 |
11:21:00.68 |
-00:50:55.4 |
HIP 55438 |
13.26 |
| 2026-10-03 00:00 |
11:21:20.64 |
-00:53:19.7 |
HIP 55438 |
15.77 |
| 2026-10-03 12:00 |
11:21:40.57 |
-00:55:44.0 |
HIP 55438 |
19.56 |
| 2026-10-04 00:00 |
11:22:00.46 |
-00:58:08.2 |
HIP 55438 |
24.03 |
| 2026-10-04 12:00 |
11:22:20.32 |
-01:00:32.4 |
HIP 55438 |
28.87 |
| 2026-10-05 00:00 |
11:22:40.15 |
-01:02:56.6 |
HIP 55438 |
33.90 |
| 2026-10-05 12:00 |
11:22:59.94 |
-01:05:20.7 |
HIP 55664 |
32.73 |
| 2026-10-06 00:00 |
11:23:19.70 |
-01:07:44.8 |
HIP 55664 |
27.99 |
| 2026-10-06 12:00 |
11:23:39.42 |
-01:10:08.9 |
HIP 55664 |
23.58 |
| 2026-10-07 00:00 |
11:23:59.11 |
-01:12:32.9 |
HIP 55664 |
19.71 |
| 2026-10-07 12:00 |
11:24:18.75 |
-01:14:56.8 |
HIP 55664 |
16.78 |
| 2026-10-08 00:00 |
11:24:38.36 |
-01:17:20.7 |
HIP 55664 |
15.30 |
| 2026-10-08 12:00 |
11:24:57.94 |
-01:19:44.5 |
HIP 55664 |
15.68 |
| 2026-10-09 00:00 |
11:25:17.47 |
-01:22:08.2 |
HIP 55664 |
17.80 |
| 2026-10-09 12:00 |
11:25:36.96 |
-01:24:31.9 |
HIP 55800 |
20.61 |
| 2026-10-10 00:00 |
11:25:56.42 |
-01:26:55.4 |
HIP 55800 |
22.24 |
| 2026-10-10 12:00 |
11:26:15.83 |
-01:29:18.9 |
HIP 55800 |
24.95 |
| 2026-10-11 00:00 |
11:26:35.20 |
-01:31:42.3 |
HIP 55941 |
22.16 |