| 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 |
1.000 |
| gb |
-1.000 |
| 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 |
17:14:26.95 |
+17:22:16.6 |
HIP 84274 |
12.86 |
| 2026-07-29 12:00 |
17:14:24.65 |
+17:21:58.4 |
HIP 84274 |
12.24 |
| 2026-07-30 00:00 |
17:14:22.38 |
+17:21:40.0 |
HIP 84274 |
11.61 |
| 2026-07-30 12:00 |
17:14:20.12 |
+17:21:21.4 |
HIP 84274 |
10.99 |
| 2026-07-31 00:00 |
17:14:17.88 |
+17:21:02.7 |
HIP 84274 |
10.38 |
| 2026-07-31 12:00 |
17:14:15.66 |
+17:20:43.8 |
HIP 84274 |
9.76 |
| 2026-08-01 00:00 |
17:14:13.46 |
+17:20:24.7 |
HIP 84274 |
9.15 |
| 2026-08-01 12:00 |
17:14:11.28 |
+17:20:05.5 |
HIP 84274 |
8.54 |
| 2026-08-02 00:00 |
17:14:09.12 |
+17:19:46.0 |
HIP 84274 |
7.94 |
| 2026-08-02 12:00 |
17:14:06.99 |
+17:19:26.5 |
HIP 84274 |
7.34 |
| 2026-08-03 00:00 |
17:14:04.87 |
+17:19:06.7 |
HIP 84274 |
6.75 |
| 2026-08-03 12:00 |
17:14:02.77 |
+17:18:46.8 |
HIP 84274 |
6.16 |
| 2026-08-04 00:00 |
17:14:00.70 |
+17:18:26.7 |
HIP 84274 |
5.57 |
| 2026-08-04 12:00 |
17:13:58.65 |
+17:18:06.5 |
HIP 84274 |
5.00 |
| 2026-08-05 00:00 |
17:13:56.61 |
+17:17:46.1 |
HIP 84274 |
4.43 |
| 2026-08-05 12:00 |
17:13:54.60 |
+17:17:25.5 |
HIP 84274 |
3.87 |
| 2026-08-06 00:00 |
17:13:52.61 |
+17:17:04.8 |
HIP 84274 |
3.33 |
| 2026-08-06 12:00 |
17:13:50.65 |
+17:16:43.9 |
HIP 84274 |
2.82 |
| 2026-08-07 00:00 |
17:13:48.70 |
+17:16:22.9 |
HIP 84274 |
2.34 |
| 2026-08-07 12:00 |
17:13:46.78 |
+17:16:01.7 |
HIP 84274 |
1.93 |
| 2026-08-08 00:00 |
17:13:44.87 |
+17:15:40.4 |
HIP 84274 |
1.62 |
| 2026-08-08 12:00 |
17:13:42.99 |
+17:15:18.9 |
HIP 84274 |
1.50 |
| 2026-08-09 00:00 |
17:13:41.14 |
+17:14:57.3 |
HIP 84274 |
1.59 |
| 2026-08-09 12:00 |
17:13:39.30 |
+17:14:35.5 |
HIP 84274 |
1.86 |
| 2026-08-10 00:00 |
17:13:37.49 |
+17:14:13.6 |
HIP 84274 |
2.25 |
| 2026-08-10 12:00 |
17:13:35.70 |
+17:13:51.5 |
HIP 84274 |
2.70 |
| 2026-08-11 00:00 |
17:13:33.93 |
+17:13:29.3 |
HIP 84274 |
3.19 |
| 2026-08-11 12:00 |
17:13:32.19 |
+17:13:07.0 |
HIP 84274 |
3.70 |
| 2026-08-12 00:00 |
17:13:30.47 |
+17:12:44.5 |
HIP 84274 |
4.22 |
| 2026-08-12 12:00 |
17:13:28.77 |
+17:12:21.9 |
HIP 84274 |
4.75 |
| 2026-08-13 00:00 |
17:13:27.10 |
+17:11:59.1 |
HIP 84274 |
5.28 |
| 2026-08-13 12:00 |
17:13:25.45 |
+17:11:36.2 |
HIP 84274 |
5.81 |
| 2026-08-14 00:00 |
17:13:23.82 |
+17:11:13.2 |
HIP 84274 |
6.35 |
| 2026-08-14 12:00 |
17:13:22.22 |
+17:10:50.1 |
HIP 84274 |
6.88 |
| 2026-08-15 00:00 |
17:13:20.64 |
+17:10:26.8 |
HIP 84274 |
7.42 |
| 2026-08-15 12:00 |
17:13:19.08 |
+17:10:03.5 |
HIP 84274 |
7.95 |
| 2026-08-16 00:00 |
17:13:17.55 |
+17:09:39.9 |
HIP 84274 |
8.49 |
| 2026-08-16 12:00 |
17:13:16.04 |
+17:09:16.3 |
HIP 84274 |
9.02 |
| 2026-08-17 00:00 |
17:13:14.56 |
+17:08:52.6 |
HIP 84274 |
9.55 |
| 2026-08-17 12:00 |
17:13:13.10 |
+17:08:28.7 |
HIP 84274 |
10.08 |
| 2026-08-18 00:00 |
17:13:11.67 |
+17:08:04.8 |
HIP 84274 |
10.60 |
| 2026-08-18 12:00 |
17:13:10.25 |
+17:07:40.7 |
HIP 84274 |
11.12 |
| 2026-08-19 00:00 |
17:13:08.87 |
+17:07:16.5 |
HIP 84274 |
11.65 |