| Parameter |
Value |
| Designation |
125P/Spacewatch |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-02-17T02:03:36.748800Z |
| Orbit solution date (soln_date, UTC) |
2024-10-29T14:53:15Z |
| Obs used |
1297 |
| NEO |
- |
| M1 |
12.900 |
| K1 |
16.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-08-11.0000000 |
| e |
0.51269168 |
| q (au) |
1.523187 |
| a (au) |
3.125715 |
| i (deg) |
9.988031 |
| Ω (om, deg) |
153.195189 |
| ω (w, deg) |
87.145345 |
| M (ma, deg) |
161.393997 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.400 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.400 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.850 |
| k |
0.999 |
| 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) |
| 2026-07-29 00:00 |
04:07:54.45 |
+11:43:24.9 |
HIP 19316 |
29.18 |
| 2026-07-29 12:00 |
04:08:12.62 |
+11:43:25.3 |
HIP 19427 |
25.97 |
| 2026-07-30 00:00 |
04:08:30.66 |
+11:43:24.8 |
HIP 19427 |
22.56 |
| 2026-07-30 12:00 |
04:08:48.58 |
+11:43:23.6 |
HIP 19427 |
19.56 |
| 2026-07-31 00:00 |
04:09:06.37 |
+11:43:21.7 |
HIP 19427 |
17.17 |
| 2026-07-31 12:00 |
04:09:24.04 |
+11:43:19.0 |
HIP 19427 |
15.65 |
| 2026-08-01 00:00 |
04:09:41.58 |
+11:43:15.5 |
HIP 19427 |
15.23 |
| 2026-08-01 12:00 |
04:09:58.98 |
+11:43:11.3 |
HIP 19427 |
15.98 |
| 2026-08-02 00:00 |
04:10:16.26 |
+11:43:06.3 |
HIP 19427 |
17.72 |
| 2026-08-02 12:00 |
04:10:33.41 |
+11:43:00.5 |
HIP 19427 |
20.18 |
| 2026-08-03 00:00 |
04:10:50.42 |
+11:42:54.0 |
HIP 19481 |
22.86 |
| 2026-08-03 12:00 |
04:11:07.30 |
+11:42:46.7 |
HIP 19481 |
24.56 |
| 2026-08-04 00:00 |
04:11:24.05 |
+11:42:38.7 |
HIP 19481 |
26.78 |
| 2026-08-04 12:00 |
04:11:40.66 |
+11:42:29.9 |
HIP 19481 |
29.40 |
| 2026-08-05 00:00 |
04:11:57.13 |
+11:42:20.3 |
HIP 19481 |
32.30 |
| 2026-08-05 12:00 |
04:12:13.46 |
+11:42:09.9 |
HIP 19663 |
32.92 |
| 2026-08-06 00:00 |
04:12:29.66 |
+11:41:58.8 |
HIP 19663 |
31.98 |
| 2026-08-06 12:00 |
04:12:45.71 |
+11:41:47.0 |
HIP 19663 |
31.50 |
| 2026-08-07 00:00 |
04:13:01.63 |
+11:41:34.3 |
HIP 19663 |
31.50 |
| 2026-08-07 12:00 |
04:13:17.40 |
+11:41:20.9 |
HIP 19663 |
31.95 |
| 2026-08-08 00:00 |
04:13:33.03 |
+11:41:06.8 |
HIP 19663 |
32.84 |
| 2026-08-08 12:00 |
04:13:48.51 |
+11:40:51.8 |
HIP 19663 |
34.11 |
| 2026-08-09 00:00 |
04:14:03.85 |
+11:40:36.1 |
HIP 19663 |
35.71 |
| 2026-08-09 12:00 |
04:14:19.04 |
+11:40:19.7 |
HIP 19886 |
35.12 |
| 2026-08-10 00:00 |
04:14:34.08 |
+11:40:02.4 |
HIP 19886 |
32.94 |
| 2026-08-10 12:00 |
04:14:48.97 |
+11:39:44.4 |
HIP 19886 |
31.08 |
| 2026-08-11 00:00 |
04:15:03.71 |
+11:39:25.7 |
HIP 19970 |
29.12 |
| 2026-08-11 12:00 |
04:15:18.29 |
+11:39:06.2 |
HIP 19970 |
25.68 |
| 2026-08-12 00:00 |
04:15:32.73 |
+11:38:45.9 |
HIP 19970 |
22.32 |
| 2026-08-12 12:00 |
04:15:47.01 |
+11:38:24.9 |
HIP 19970 |
19.06 |
| 2026-08-13 00:00 |
04:16:01.13 |
+11:38:03.1 |
HIP 19970 |
15.93 |
| 2026-08-13 12:00 |
04:16:15.09 |
+11:37:40.5 |
HIP 19970 |
13.00 |
| 2026-08-14 00:00 |
04:16:28.90 |
+11:37:17.2 |
HIP 19970 |
10.40 |
| 2026-08-14 12:00 |
04:16:42.55 |
+11:36:53.1 |
HIP 19970 |
8.40 |
| 2026-08-15 00:00 |
04:16:56.04 |
+11:36:28.3 |
HIP 19970 |
7.44 |
| 2026-08-15 12:00 |
04:17:09.37 |
+11:36:02.8 |
HIP 19970 |
7.87 |
| 2026-08-16 00:00 |
04:17:22.54 |
+11:35:36.4 |
HIP 19970 |
9.46 |
| 2026-08-16 12:00 |
04:17:35.54 |
+11:35:09.4 |
HIP 19970 |
11.71 |
| 2026-08-17 00:00 |
04:17:48.38 |
+11:34:41.6 |
HIP 19970 |
14.30 |
| 2026-08-17 12:00 |
04:18:01.05 |
+11:34:13.0 |
HIP 19970 |
17.04 |
| 2026-08-18 00:00 |
04:18:13.56 |
+11:33:43.7 |
HIP 19970 |
19.86 |
| 2026-08-18 12:00 |
04:18:25.90 |
+11:33:13.7 |
HIP 19970 |
22.72 |
| 2026-08-19 00:00 |
04:18:38.07 |
+11:32:42.9 |
HIP 19970 |
25.57 |