C/2004 S1 (Van Ness)
| Parameter |
Value |
| Designation |
C/2004 S1 (Van Ness) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-12-08T22:06:25.934400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:43Z |
| Obs used |
122 |
| NEO |
- |
| M1 |
16.000 |
| K1 |
7.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2004-10-08.0000000 |
| e |
0.99999485 |
| q (au) |
0.681767 |
| a (au) |
132276.648552 |
| i (deg) |
114.666841 |
| Ω (om, deg) |
19.219692 |
| ω (w, deg) |
92.816645 |
| M (ma, deg) |
359.999999 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.981 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.981 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.680 |
| k |
0.991 |
| 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) |
| 2026-02-03 00:00 |
07:44:57.63 |
-44:39:06.9 |
HIP 37887 |
12.03 |
| 2026-02-03 12:00 |
07:44:53.78 |
-44:38:50.8 |
HIP 37887 |
12.75 |
| 2026-02-04 00:00 |
07:44:49.95 |
-44:38:34.5 |
HIP 37887 |
13.47 |
| 2026-02-04 12:00 |
07:44:46.12 |
-44:38:17.9 |
HIP 37887 |
14.20 |
| 2026-02-05 00:00 |
07:44:42.31 |
-44:38:00.9 |
HIP 37887 |
14.92 |
| 2026-02-05 12:00 |
07:44:38.52 |
-44:37:43.6 |
HIP 37887 |
15.65 |
| 2026-02-06 00:00 |
07:44:34.74 |
-44:37:26.0 |
HIP 37887 |
16.38 |
| 2026-02-06 12:00 |
07:44:30.97 |
-44:37:08.1 |
HIP 37887 |
17.11 |
| 2026-02-07 00:00 |
07:44:27.22 |
-44:36:49.9 |
HIP 37887 |
17.84 |
| 2026-02-07 12:00 |
07:44:23.48 |
-44:36:31.3 |
HIP 37887 |
18.57 |
| 2026-02-08 00:00 |
07:44:19.75 |
-44:36:12.5 |
HIP 37887 |
19.30 |
| 2026-02-08 12:00 |
07:44:16.05 |
-44:35:53.4 |
HIP 37856 |
19.64 |
| 2026-02-09 00:00 |
07:44:12.35 |
-44:35:33.9 |
HIP 37856 |
19.91 |
| 2026-02-09 12:00 |
07:44:08.68 |
-44:35:14.2 |
HIP 37856 |
20.20 |
| 2026-02-10 00:00 |
07:44:05.02 |
-44:34:54.1 |
HIP 37856 |
20.50 |
| 2026-02-10 12:00 |
07:44:01.37 |
-44:34:33.8 |
HIP 37856 |
20.83 |
| 2026-02-11 00:00 |
07:43:57.74 |
-44:34:13.1 |
HIP 37856 |
21.16 |
| 2026-02-11 12:00 |
07:43:54.13 |
-44:33:52.2 |
HIP 37856 |
21.51 |
| 2026-02-12 00:00 |
07:43:50.54 |
-44:33:30.9 |
HIP 37856 |
21.88 |
| 2026-02-12 12:00 |
07:43:46.96 |
-44:33:09.4 |
HIP 37856 |
22.26 |
| 2026-02-13 00:00 |
07:43:43.41 |
-44:32:47.6 |
HIP 37856 |
22.65 |
| 2026-02-13 12:00 |
07:43:39.87 |
-44:32:25.5 |
HIP 37856 |
23.05 |
| 2026-02-14 00:00 |
07:43:36.35 |
-44:32:03.1 |
HIP 37856 |
23.46 |
| 2026-02-14 12:00 |
07:43:32.85 |
-44:31:40.4 |
HIP 37856 |
23.89 |
| 2026-02-15 00:00 |
07:43:29.36 |
-44:31:17.4 |
HIP 37461 |
23.68 |
| 2026-02-15 12:00 |
07:43:25.90 |
-44:30:54.2 |
HIP 37461 |
23.20 |
| 2026-02-16 00:00 |
07:43:22.46 |
-44:30:30.7 |
HIP 37461 |
22.75 |
| 2026-02-16 12:00 |
07:43:19.03 |
-44:30:06.9 |
HIP 37461 |
22.31 |
| 2026-02-17 00:00 |
07:43:15.63 |
-44:29:42.8 |
HIP 37461 |
21.89 |
| 2026-02-17 12:00 |
07:43:12.25 |
-44:29:18.5 |
HIP 37461 |
21.49 |
| 2026-02-18 00:00 |
07:43:08.88 |
-44:28:53.8 |
HIP 37461 |
21.12 |
| 2026-02-18 12:00 |
07:43:05.54 |
-44:28:29.0 |
HIP 37461 |
20.77 |
| 2026-02-19 00:00 |
07:43:02.22 |
-44:28:03.8 |
HIP 37461 |
20.44 |
| 2026-02-19 12:00 |
07:42:58.93 |
-44:27:38.4 |
HIP 37461 |
20.15 |
| 2026-02-20 00:00 |
07:42:55.65 |
-44:27:12.7 |
HIP 37461 |
19.87 |
| 2026-02-20 12:00 |
07:42:52.40 |
-44:26:46.8 |
HIP 37461 |
19.63 |
| 2026-02-21 00:00 |
07:42:49.16 |
-44:26:20.6 |
HIP 37461 |
19.42 |
| 2026-02-21 12:00 |
07:42:45.96 |
-44:25:54.2 |
HIP 37461 |
19.24 |
| 2026-02-22 00:00 |
07:42:42.77 |
-44:25:27.5 |
HIP 37461 |
19.08 |
| 2026-02-22 12:00 |
07:42:39.61 |
-44:25:00.6 |
HIP 37461 |
18.96 |
| 2026-02-23 00:00 |
07:42:36.47 |
-44:24:33.4 |
HIP 37461 |
18.88 |
| 2026-02-23 12:00 |
07:42:33.35 |
-44:24:06.0 |
HIP 37461 |
18.82 |
| 2026-02-24 00:00 |
07:42:30.26 |
-44:23:38.3 |
HIP 37461 |
18.80 |