| 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) |
| 2026-03-26 00:00 |
02:22:40.30 |
+05:52:21.7 |
HIP 11132 |
11.42 |
| 2026-03-26 12:00 |
02:23:05.46 |
+05:54:45.8 |
HIP 11132 |
5.64 |
| 2026-03-27 00:00 |
02:23:30.66 |
+05:57:09.6 |
HIP 11132 |
4.81 |
| 2026-03-27 12:00 |
02:23:55.92 |
+05:59:33.3 |
HIP 11132 |
10.23 |
| 2026-03-28 00:00 |
02:24:21.23 |
+06:01:56.7 |
HIP 11132 |
16.64 |
| 2026-03-28 12:00 |
02:24:46.59 |
+06:04:20.0 |
HIP 11132 |
23.25 |
| 2026-03-29 00:00 |
02:25:12.00 |
+06:06:43.0 |
HIP 11360 |
19.29 |
| 2026-03-29 12:00 |
02:25:37.46 |
+06:09:05.8 |
HIP 11360 |
12.82 |
| 2026-03-30 00:00 |
02:26:02.98 |
+06:11:28.3 |
HIP 11360 |
6.92 |
| 2026-03-30 12:00 |
02:26:28.54 |
+06:13:50.7 |
HIP 11360 |
4.82 |
| 2026-03-31 00:00 |
02:26:54.14 |
+06:16:12.8 |
HIP 11411 |
3.49 |
| 2026-03-31 12:00 |
02:27:19.80 |
+06:18:34.6 |
HIP 11411 |
6.43 |
| 2026-04-01 00:00 |
02:27:45.50 |
+06:20:56.2 |
HIP 11411 |
12.78 |
| 2026-04-01 12:00 |
02:28:11.25 |
+06:23:17.6 |
HIP 11411 |
19.44 |
| 2026-04-02 00:00 |
02:28:37.04 |
+06:25:38.7 |
HIP 11563 |
23.78 |
| 2026-04-02 12:00 |
02:29:02.88 |
+06:27:59.6 |
HIP 11563 |
20.89 |
| 2026-04-03 00:00 |
02:29:28.76 |
+06:30:20.2 |
HIP 11563 |
20.02 |
| 2026-04-03 12:00 |
02:29:54.69 |
+06:32:40.5 |
HIP 11563 |
21.43 |
| 2026-04-04 00:00 |
02:30:20.66 |
+06:35:00.6 |
HIP 11563 |
24.74 |
| 2026-04-04 12:00 |
02:30:46.67 |
+06:37:20.4 |
HIP 11798 |
21.98 |
| 2026-04-05 00:00 |
02:31:12.72 |
+06:39:39.9 |
HIP 11798 |
15.14 |
| 2026-04-05 12:00 |
02:31:38.82 |
+06:41:59.1 |
HIP 11798 |
8.35 |
| 2026-04-06 00:00 |
02:32:04.95 |
+06:44:18.1 |
HIP 11798 |
2.19 |
| 2026-04-06 12:00 |
02:32:31.13 |
+06:46:36.8 |
HIP 11798 |
5.91 |
| 2026-04-07 00:00 |
02:32:57.34 |
+06:48:55.2 |
HIP 11854 |
8.48 |
| 2026-04-07 12:00 |
02:33:23.60 |
+06:51:13.3 |
HIP 11854 |
8.54 |
| 2026-04-08 00:00 |
02:33:49.89 |
+06:53:31.1 |
HIP 11854 |
13.02 |
| 2026-04-08 12:00 |
02:34:16.22 |
+06:55:48.6 |
HIP 11854 |
19.04 |
| 2026-04-09 00:00 |
02:34:42.59 |
+06:58:05.8 |
HIP 12114 |
20.80 |
| 2026-04-09 12:00 |
02:35:09.00 |
+07:00:22.6 |
HIP 12114 |
15.48 |
| 2026-04-10 00:00 |
02:35:35.44 |
+07:02:39.2 |
HIP 12114 |
11.95 |
| 2026-04-10 12:00 |
02:36:01.92 |
+07:04:55.4 |
HIP 12114 |
11.93 |
| 2026-04-11 00:00 |
02:36:28.43 |
+07:07:11.3 |
HIP 12114 |
15.44 |
| 2026-04-11 12:00 |
02:36:54.98 |
+07:09:26.9 |
HIP 12114 |
20.77 |
| 2026-04-12 00:00 |
02:37:21.56 |
+07:11:42.2 |
HIP 12182 |
19.54 |
| 2026-04-12 12:00 |
02:37:48.17 |
+07:13:57.1 |
HIP 12182 |
20.66 |
| 2026-04-13 00:00 |
02:38:14.82 |
+07:16:11.7 |
HIP 12323 |
20.44 |
| 2026-04-13 12:00 |
02:38:41.50 |
+07:18:25.9 |
HIP 12323 |
21.63 |
| 2026-04-14 00:00 |
02:39:08.21 |
+07:20:39.8 |
HIP 12420 |
19.93 |
| 2026-04-14 12:00 |
02:39:34.95 |
+07:22:53.4 |
HIP 12420 |
15.12 |
| 2026-04-15 00:00 |
02:40:01.72 |
+07:25:06.5 |
HIP 12420 |
12.56 |
| 2026-04-15 12:00 |
02:40:28.52 |
+07:27:19.4 |
HIP 12420 |
13.61 |
| 2026-04-16 00:00 |
02:40:55.35 |
+07:29:31.8 |
HIP 12420 |
17.64 |