| 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) |
| 2026-05-12 00:00 |
03:04:33.08 |
+09:14:19.7 |
HIP 14319 |
12.77 |
| 2026-05-12 12:00 |
03:05:00.50 |
+09:16:07.7 |
HIP 14319 |
15.21 |
| 2026-05-13 00:00 |
03:05:27.92 |
+09:17:55.1 |
HIP 14319 |
19.93 |
| 2026-05-13 12:00 |
03:05:55.34 |
+09:19:41.9 |
HIP 14319 |
25.71 |
| 2026-05-14 00:00 |
03:06:22.74 |
+09:21:28.2 |
HIP 14319 |
31.96 |
| 2026-05-14 12:00 |
03:06:50.15 |
+09:23:14.0 |
HIP 14630 |
37.51 |
| 2026-05-15 00:00 |
03:07:17.54 |
+09:24:59.1 |
HIP 14630 |
30.89 |
| 2026-05-15 12:00 |
03:07:44.93 |
+09:26:43.8 |
HIP 14630 |
24.48 |
| 2026-05-16 00:00 |
03:08:12.31 |
+09:28:27.8 |
HIP 14630 |
18.49 |
| 2026-05-16 12:00 |
03:08:39.68 |
+09:30:11.3 |
HIP 14630 |
13.50 |
| 2026-05-17 00:00 |
03:09:07.04 |
+09:31:54.3 |
HIP 14630 |
10.93 |
| 2026-05-17 12:00 |
03:09:34.39 |
+09:33:36.6 |
HIP 14630 |
12.40 |
| 2026-05-18 00:00 |
03:10:01.72 |
+09:35:18.4 |
HIP 14716 |
13.73 |
| 2026-05-18 12:00 |
03:10:29.05 |
+09:36:59.6 |
HIP 14716 |
13.21 |
| 2026-05-19 00:00 |
03:10:56.36 |
+09:38:40.2 |
HIP 14716 |
16.03 |
| 2026-05-19 12:00 |
03:11:23.66 |
+09:40:20.2 |
HIP 14792 |
19.85 |
| 2026-05-20 00:00 |
03:11:50.94 |
+09:41:59.6 |
HIP 14792 |
21.30 |
| 2026-05-20 12:00 |
03:12:18.21 |
+09:43:38.5 |
HIP 14792 |
24.69 |
| 2026-05-21 00:00 |
03:12:45.46 |
+09:45:16.7 |
HIP 14792 |
29.34 |
| 2026-05-21 12:00 |
03:13:12.70 |
+09:46:54.4 |
HIP 14792 |
34.75 |
| 2026-05-22 00:00 |
03:13:39.92 |
+09:48:31.5 |
HIP 14906 |
36.41 |
| 2026-05-22 12:00 |
03:14:07.12 |
+09:50:07.9 |
HIP 15054 |
37.12 |
| 2026-05-23 00:00 |
03:14:34.31 |
+09:51:43.8 |
HIP 15054 |
36.45 |
| 2026-05-23 12:00 |
03:15:01.47 |
+09:53:19.0 |
HIP 15288 |
36.27 |
| 2026-05-24 00:00 |
03:15:28.61 |
+09:54:53.7 |
HIP 15288 |
29.57 |
| 2026-05-24 12:00 |
03:15:55.74 |
+09:56:27.7 |
HIP 15288 |
22.98 |
| 2026-05-25 00:00 |
03:16:22.84 |
+09:58:01.1 |
HIP 15288 |
16.63 |
| 2026-05-25 12:00 |
03:16:49.92 |
+09:59:34.0 |
HIP 15288 |
10.91 |
| 2026-05-26 00:00 |
03:17:16.98 |
+10:01:06.2 |
HIP 15288 |
7.44 |
| 2026-05-26 12:00 |
03:17:44.02 |
+10:02:37.8 |
HIP 15288 |
9.23 |
| 2026-05-27 00:00 |
03:18:11.04 |
+10:04:08.8 |
HIP 15288 |
14.43 |
| 2026-05-27 12:00 |
03:18:38.03 |
+10:05:39.1 |
HIP 15401 |
13.12 |
| 2026-05-28 00:00 |
03:19:04.99 |
+10:07:08.9 |
HIP 15401 |
13.74 |
| 2026-05-28 12:00 |
03:19:31.94 |
+10:08:38.0 |
HIP 15401 |
17.26 |
| 2026-05-29 00:00 |
03:19:58.85 |
+10:10:06.5 |
HIP 15401 |
22.34 |
| 2026-05-29 12:00 |
03:20:25.74 |
+10:11:34.4 |
HIP 15401 |
28.15 |
| 2026-05-30 00:00 |
03:20:52.61 |
+10:13:01.6 |
HIP 15633 |
25.54 |
| 2026-05-30 12:00 |
03:21:19.44 |
+10:14:28.2 |
HIP 15633 |
23.32 |
| 2026-05-31 00:00 |
03:21:46.25 |
+10:15:54.2 |
HIP 15633 |
22.95 |
| 2026-05-31 12:00 |
03:22:13.04 |
+10:17:19.6 |
HIP 15633 |
24.52 |
| 2026-06-01 00:00 |
03:22:39.79 |
+10:18:44.3 |
HIP 15837 |
21.58 |
| 2026-06-01 12:00 |
03:23:06.51 |
+10:20:08.4 |
HIP 15837 |
15.09 |
| 2026-06-02 00:00 |
03:23:33.21 |
+10:21:31.9 |
HIP 15837 |
8.96 |