| 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) |
| 2026-06-01 00:00 |
07:41:53.10 |
-42:34:55.3 |
HIP 37577 |
8.86 |
| 2026-06-01 12:00 |
07:41:55.64 |
-42:34:32.4 |
HIP 37577 |
8.36 |
| 2026-06-02 00:00 |
07:41:58.20 |
-42:34:09.7 |
HIP 37577 |
7.88 |
| 2026-06-02 12:00 |
07:42:00.78 |
-42:33:47.2 |
HIP 37577 |
7.41 |
| 2026-06-03 00:00 |
07:42:03.37 |
-42:33:25.0 |
HIP 37577 |
6.95 |
| 2026-06-03 12:00 |
07:42:05.99 |
-42:33:03.0 |
HIP 37577 |
6.52 |
| 2026-06-04 00:00 |
07:42:08.63 |
-42:32:41.3 |
HIP 37577 |
6.11 |
| 2026-06-04 12:00 |
07:42:11.28 |
-42:32:19.9 |
HIP 37577 |
5.73 |
| 2026-06-05 00:00 |
07:42:13.96 |
-42:31:58.6 |
HIP 37577 |
5.39 |
| 2026-06-05 12:00 |
07:42:16.65 |
-42:31:37.7 |
HIP 37577 |
5.09 |
| 2026-06-06 00:00 |
07:42:19.36 |
-42:31:17.0 |
HIP 37577 |
4.85 |
| 2026-06-06 12:00 |
07:42:22.09 |
-42:30:56.6 |
HIP 37577 |
4.66 |
| 2026-06-07 00:00 |
07:42:24.84 |
-42:30:36.4 |
HIP 37577 |
4.55 |
| 2026-06-07 12:00 |
07:42:27.60 |
-42:30:16.5 |
HIP 37577 |
4.51 |
| 2026-06-08 00:00 |
07:42:30.39 |
-42:29:56.8 |
HIP 37577 |
4.54 |
| 2026-06-08 12:00 |
07:42:33.19 |
-42:29:37.4 |
HIP 37577 |
4.65 |
| 2026-06-09 00:00 |
07:42:36.00 |
-42:29:18.3 |
HIP 37577 |
4.83 |
| 2026-06-09 12:00 |
07:42:38.84 |
-42:28:59.4 |
HIP 37577 |
5.07 |
| 2026-06-10 00:00 |
07:42:41.69 |
-42:28:40.8 |
HIP 37577 |
5.37 |
| 2026-06-10 12:00 |
07:42:44.56 |
-42:28:22.5 |
HIP 37577 |
5.71 |
| 2026-06-11 00:00 |
07:42:47.44 |
-42:28:04.4 |
HIP 37577 |
6.09 |
| 2026-06-11 12:00 |
07:42:50.34 |
-42:27:46.6 |
HIP 37577 |
6.50 |
| 2026-06-12 00:00 |
07:42:53.26 |
-42:27:29.1 |
HIP 37577 |
6.94 |
| 2026-06-12 12:00 |
07:42:56.19 |
-42:27:11.9 |
HIP 37577 |
7.40 |
| 2026-06-13 00:00 |
07:42:59.14 |
-42:26:54.9 |
HIP 37577 |
7.88 |
| 2026-06-13 12:00 |
07:43:02.10 |
-42:26:38.2 |
HIP 37577 |
8.37 |
| 2026-06-14 00:00 |
07:43:05.08 |
-42:26:21.8 |
HIP 37577 |
8.88 |
| 2026-06-14 12:00 |
07:43:08.07 |
-42:26:05.6 |
HIP 37577 |
9.39 |
| 2026-06-15 00:00 |
07:43:11.08 |
-42:25:49.7 |
HIP 37577 |
9.92 |
| 2026-06-15 12:00 |
07:43:14.10 |
-42:25:34.2 |
HIP 37577 |
10.45 |
| 2026-06-16 00:00 |
07:43:17.14 |
-42:25:18.9 |
HIP 37577 |
10.99 |
| 2026-06-16 12:00 |
07:43:20.19 |
-42:25:03.8 |
HIP 37577 |
11.53 |
| 2026-06-17 00:00 |
07:43:23.25 |
-42:24:49.1 |
HIP 37577 |
12.08 |
| 2026-06-17 12:00 |
07:43:26.33 |
-42:24:34.6 |
HIP 37577 |
12.63 |
| 2026-06-18 00:00 |
07:43:29.42 |
-42:24:20.5 |
HIP 37577 |
13.19 |
| 2026-06-18 12:00 |
07:43:32.53 |
-42:24:06.6 |
HIP 37577 |
13.75 |
| 2026-06-19 00:00 |
07:43:35.64 |
-42:23:53.0 |
HIP 37577 |
14.31 |
| 2026-06-19 12:00 |
07:43:38.77 |
-42:23:39.6 |
HIP 37577 |
14.88 |
| 2026-06-20 00:00 |
07:43:41.91 |
-42:23:26.6 |
HIP 37565 |
15.36 |
| 2026-06-20 12:00 |
07:43:45.07 |
-42:23:13.9 |
HIP 37565 |
15.69 |
| 2026-06-21 00:00 |
07:43:48.23 |
-42:23:01.4 |
HIP 37565 |
16.05 |
| 2026-06-21 12:00 |
07:43:51.41 |
-42:22:49.2 |
HIP 37565 |
16.42 |
| 2026-06-22 00:00 |
07:43:54.60 |
-42:22:37.4 |
HIP 37565 |
16.81 |