| Parameter |
Value |
| Designation |
C/2004 H6 (SWAN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2004-05-12T16:30:22.481280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:40Z |
| Obs used |
285 |
| NEO |
- |
| M1 |
10.300 |
| K1 |
25.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2004-07-30.0000000 |
| e |
1.00063094 |
| q (au) |
0.776283 |
| a (au) |
-1230.353854 |
| i (deg) |
107.663846 |
| Ω (om, deg) |
317.245375 |
| ω (w, deg) |
269.049126 |
| M (ma, deg) |
0.001788 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.596 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.596 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2004-05-14 |
2004-09-08 |
+7.8785 |
-3.557 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
18:10:21.90 |
+42:44:17.5 |
HIP 88874 |
20.04 |
| 2026-03-26 12:00 |
18:10:21.67 |
+42:44:55.8 |
HIP 88874 |
20.20 |
| 2026-03-27 00:00 |
18:10:21.41 |
+42:45:34.2 |
HIP 88874 |
20.38 |
| 2026-03-27 12:00 |
18:10:21.12 |
+42:46:12.5 |
HIP 88874 |
20.57 |
| 2026-03-28 00:00 |
18:10:20.80 |
+42:46:50.8 |
HIP 88874 |
20.78 |
| 2026-03-28 12:00 |
18:10:20.45 |
+42:47:29.1 |
HIP 88874 |
20.99 |
| 2026-03-29 00:00 |
18:10:20.06 |
+42:48:07.3 |
HIP 88874 |
21.22 |
| 2026-03-29 12:00 |
18:10:19.64 |
+42:48:45.5 |
HIP 88874 |
21.46 |
| 2026-03-30 00:00 |
18:10:19.19 |
+42:49:23.7 |
HIP 88874 |
21.71 |
| 2026-03-30 12:00 |
18:10:18.71 |
+42:50:01.8 |
HIP 88874 |
21.97 |
| 2026-03-31 00:00 |
18:10:18.20 |
+42:50:39.9 |
HIP 88874 |
22.24 |
| 2026-03-31 12:00 |
18:10:17.65 |
+42:51:17.9 |
HIP 88874 |
22.52 |
| 2026-04-01 00:00 |
18:10:17.07 |
+42:51:56.0 |
HIP 88874 |
22.82 |
| 2026-04-01 12:00 |
18:10:16.46 |
+42:52:33.9 |
HIP 88874 |
23.12 |
| 2026-04-02 00:00 |
18:10:15.82 |
+42:53:11.8 |
HIP 88874 |
23.42 |
| 2026-04-02 12:00 |
18:10:15.15 |
+42:53:49.7 |
HIP 88874 |
23.74 |
| 2026-04-03 00:00 |
18:10:14.44 |
+42:54:27.5 |
HIP 88874 |
24.07 |
| 2026-04-03 12:00 |
18:10:13.71 |
+42:55:05.2 |
HIP 88874 |
24.40 |
| 2026-04-04 00:00 |
18:10:12.94 |
+42:55:42.9 |
HIP 88874 |
24.74 |
| 2026-04-04 12:00 |
18:10:12.14 |
+42:56:20.5 |
HIP 88874 |
25.09 |
| 2026-04-05 00:00 |
18:10:11.30 |
+42:56:58.0 |
HIP 88874 |
25.44 |
| 2026-04-05 12:00 |
18:10:10.44 |
+42:57:35.5 |
HIP 88882 |
25.61 |
| 2026-04-06 00:00 |
18:10:09.55 |
+42:58:12.9 |
HIP 88882 |
25.02 |
| 2026-04-06 12:00 |
18:10:08.62 |
+42:58:50.2 |
HIP 88882 |
24.43 |
| 2026-04-07 00:00 |
18:10:07.66 |
+42:59:27.5 |
HIP 88882 |
23.84 |
| 2026-04-07 12:00 |
18:10:06.67 |
+43:00:04.7 |
HIP 88882 |
23.25 |
| 2026-04-08 00:00 |
18:10:05.65 |
+43:00:41.8 |
HIP 88882 |
22.66 |
| 2026-04-08 12:00 |
18:10:04.60 |
+43:01:18.8 |
HIP 88882 |
22.07 |
| 2026-04-09 00:00 |
18:10:03.51 |
+43:01:55.7 |
HIP 88882 |
21.48 |
| 2026-04-09 12:00 |
18:10:02.40 |
+43:02:32.5 |
HIP 88882 |
20.89 |
| 2026-04-10 00:00 |
18:10:01.25 |
+43:03:09.2 |
HIP 88882 |
20.31 |
| 2026-04-10 12:00 |
18:10:00.07 |
+43:03:45.9 |
HIP 88882 |
19.72 |
| 2026-04-11 00:00 |
18:09:58.87 |
+43:04:22.4 |
HIP 88882 |
19.13 |
| 2026-04-11 12:00 |
18:09:57.63 |
+43:04:58.9 |
HIP 88882 |
18.55 |
| 2026-04-12 00:00 |
18:09:56.36 |
+43:05:35.2 |
HIP 88882 |
17.97 |
| 2026-04-12 12:00 |
18:09:55.06 |
+43:06:11.4 |
HIP 88882 |
17.39 |
| 2026-04-13 00:00 |
18:09:53.72 |
+43:06:47.5 |
HIP 88882 |
16.81 |
| 2026-04-13 12:00 |
18:09:52.36 |
+43:07:23.6 |
HIP 88882 |
16.23 |
| 2026-04-14 00:00 |
18:09:50.97 |
+43:07:59.4 |
HIP 88882 |
15.66 |
| 2026-04-14 12:00 |
18:09:49.54 |
+43:08:35.2 |
HIP 88882 |
15.09 |
| 2026-04-15 00:00 |
18:09:48.09 |
+43:09:10.9 |
HIP 88882 |
14.52 |
| 2026-04-15 12:00 |
18:09:46.60 |
+43:09:46.4 |
HIP 88882 |
13.96 |
| 2026-04-16 00:00 |
18:09:45.09 |
+43:10:21.8 |
HIP 88882 |
13.40 |