| Parameter |
Value |
| Designation |
C/2001 S1 (Skiff) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2001-06-02T08:44:15.699840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:11Z |
| Obs used |
39 |
| NEO |
- |
| M1 |
6.900 |
| K1 |
15.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2001-10-05.0000000 |
| e |
0.92987325 |
| q (au) |
3.749250 |
| a (au) |
53.463910 |
| i (deg) |
139.132817 |
| Ω (om, deg) |
330.121196 |
| ω (w, deg) |
285.171215 |
| M (ma, deg) |
0.314236 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.013 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.013 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
0.999 |
| δ90 |
9.998 |
| 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 |
17:25:27.11 |
+16:44:34.9 |
HIP 85302 |
12.34 |
| 2026-03-26 12:00 |
17:25:26.23 |
+16:45:04.4 |
HIP 85302 |
12.04 |
| 2026-03-27 00:00 |
17:25:25.33 |
+16:45:33.8 |
HIP 85302 |
11.76 |
| 2026-03-27 12:00 |
17:25:24.40 |
+16:46:03.2 |
HIP 85302 |
11.51 |
| 2026-03-28 00:00 |
17:25:23.44 |
+16:46:32.6 |
HIP 85302 |
11.28 |
| 2026-03-28 12:00 |
17:25:22.46 |
+16:47:01.9 |
HIP 85231 |
10.83 |
| 2026-03-29 00:00 |
17:25:21.45 |
+16:47:31.2 |
HIP 85231 |
10.29 |
| 2026-03-29 12:00 |
17:25:20.41 |
+16:48:00.5 |
HIP 85231 |
9.75 |
| 2026-03-30 00:00 |
17:25:19.35 |
+16:48:29.6 |
HIP 85231 |
9.20 |
| 2026-03-30 12:00 |
17:25:18.27 |
+16:48:58.8 |
HIP 85231 |
8.66 |
| 2026-03-31 00:00 |
17:25:17.15 |
+16:49:27.9 |
HIP 85231 |
8.11 |
| 2026-03-31 12:00 |
17:25:16.01 |
+16:49:56.9 |
HIP 85231 |
7.55 |
| 2026-04-01 00:00 |
17:25:14.85 |
+16:50:25.9 |
HIP 85231 |
7.00 |
| 2026-04-01 12:00 |
17:25:13.66 |
+16:50:54.8 |
HIP 85231 |
6.44 |
| 2026-04-02 00:00 |
17:25:12.44 |
+16:51:23.7 |
HIP 85231 |
5.88 |
| 2026-04-02 12:00 |
17:25:11.20 |
+16:51:52.5 |
HIP 85231 |
5.32 |
| 2026-04-03 00:00 |
17:25:09.94 |
+16:52:21.2 |
HIP 85231 |
4.76 |
| 2026-04-03 12:00 |
17:25:08.64 |
+16:52:49.9 |
HIP 85231 |
4.19 |
| 2026-04-04 00:00 |
17:25:07.33 |
+16:53:18.5 |
HIP 85231 |
3.62 |
| 2026-04-04 12:00 |
17:25:05.98 |
+16:53:47.1 |
HIP 85231 |
3.05 |
| 2026-04-05 00:00 |
17:25:04.62 |
+16:54:15.5 |
HIP 85231 |
2.48 |
| 2026-04-05 12:00 |
17:25:03.22 |
+16:54:43.9 |
HIP 85231 |
1.91 |
| 2026-04-06 00:00 |
17:25:01.81 |
+16:55:12.3 |
HIP 85231 |
1.33 |
| 2026-04-06 12:00 |
17:25:00.36 |
+16:55:40.5 |
HIP 85231 |
0.77 |
| 2026-04-07 00:00 |
17:24:58.90 |
+16:56:08.7 |
HIP 85231 |
0.30 |
| 2026-04-07 12:00 |
17:24:57.40 |
+16:56:36.8 |
HIP 85231 |
0.52 |
| 2026-04-08 00:00 |
17:24:55.89 |
+16:57:04.8 |
HIP 85231 |
1.07 |
| 2026-04-08 12:00 |
17:24:54.34 |
+16:57:32.7 |
HIP 85231 |
1.65 |
| 2026-04-09 00:00 |
17:24:52.78 |
+16:58:00.5 |
HIP 85231 |
2.24 |
| 2026-04-09 12:00 |
17:24:51.19 |
+16:58:28.2 |
HIP 85231 |
2.83 |
| 2026-04-10 00:00 |
17:24:49.57 |
+16:58:55.9 |
HIP 85231 |
3.43 |
| 2026-04-10 12:00 |
17:24:47.93 |
+16:59:23.4 |
HIP 85231 |
4.03 |
| 2026-04-11 00:00 |
17:24:46.27 |
+16:59:50.9 |
HIP 85231 |
4.64 |
| 2026-04-11 12:00 |
17:24:44.58 |
+17:00:18.3 |
HIP 85231 |
5.24 |
| 2026-04-12 00:00 |
17:24:42.87 |
+17:00:45.5 |
HIP 85231 |
5.85 |
| 2026-04-12 12:00 |
17:24:41.14 |
+17:01:12.7 |
HIP 85231 |
6.46 |
| 2026-04-13 00:00 |
17:24:39.38 |
+17:01:39.7 |
HIP 85231 |
7.08 |
| 2026-04-13 12:00 |
17:24:37.59 |
+17:02:06.7 |
HIP 85231 |
7.69 |
| 2026-04-14 00:00 |
17:24:35.79 |
+17:02:33.5 |
HIP 85231 |
8.31 |
| 2026-04-14 12:00 |
17:24:33.96 |
+17:03:00.2 |
HIP 85231 |
8.93 |
| 2026-04-15 00:00 |
17:24:32.10 |
+17:03:26.8 |
HIP 85231 |
9.56 |
| 2026-04-15 12:00 |
17:24:30.23 |
+17:03:53.3 |
HIP 85231 |
10.18 |
| 2026-04-16 00:00 |
17:24:28.33 |
+17:04:19.7 |
HIP 85231 |
10.81 |