| 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) |
| 2026-07-29 00:00 |
17:58:36.11 |
+43:42:42.4 |
HIP 87944 |
19.08 |
| 2026-07-29 12:00 |
17:58:33.05 |
+43:42:21.0 |
HIP 87944 |
18.54 |
| 2026-07-30 00:00 |
17:58:30.02 |
+43:41:59.3 |
HIP 87944 |
18.01 |
| 2026-07-30 12:00 |
17:58:27.00 |
+43:41:37.4 |
HIP 87944 |
17.49 |
| 2026-07-31 00:00 |
17:58:24.00 |
+43:41:15.2 |
HIP 87944 |
16.97 |
| 2026-07-31 12:00 |
17:58:21.03 |
+43:40:52.7 |
HIP 87944 |
16.46 |
| 2026-08-01 00:00 |
17:58:18.07 |
+43:40:30.1 |
HIP 87944 |
15.96 |
| 2026-08-01 12:00 |
17:58:15.14 |
+43:40:07.1 |
HIP 87944 |
15.46 |
| 2026-08-02 00:00 |
17:58:12.22 |
+43:39:44.0 |
HIP 87944 |
14.98 |
| 2026-08-02 12:00 |
17:58:09.33 |
+43:39:20.6 |
HIP 87944 |
14.50 |
| 2026-08-03 00:00 |
17:58:06.46 |
+43:38:56.9 |
HIP 87944 |
14.04 |
| 2026-08-03 12:00 |
17:58:03.60 |
+43:38:33.0 |
HIP 87944 |
13.58 |
| 2026-08-04 00:00 |
17:58:00.78 |
+43:38:08.9 |
HIP 87944 |
13.14 |
| 2026-08-04 12:00 |
17:57:57.97 |
+43:37:44.5 |
HIP 87944 |
12.72 |
| 2026-08-05 00:00 |
17:57:55.18 |
+43:37:20.0 |
HIP 87944 |
12.31 |
| 2026-08-05 12:00 |
17:57:52.42 |
+43:36:55.1 |
HIP 87944 |
11.92 |
| 2026-08-06 00:00 |
17:57:49.68 |
+43:36:30.1 |
HIP 87944 |
11.54 |
| 2026-08-06 12:00 |
17:57:46.96 |
+43:36:04.8 |
HIP 87944 |
11.19 |
| 2026-08-07 00:00 |
17:57:44.27 |
+43:35:39.3 |
HIP 87944 |
10.86 |
| 2026-08-07 12:00 |
17:57:41.60 |
+43:35:13.5 |
HIP 87944 |
10.55 |
| 2026-08-08 00:00 |
17:57:38.95 |
+43:34:47.6 |
HIP 87944 |
10.28 |
| 2026-08-08 12:00 |
17:57:36.33 |
+43:34:21.4 |
HIP 87944 |
10.03 |
| 2026-08-09 00:00 |
17:57:33.73 |
+43:33:55.0 |
HIP 87944 |
9.81 |
| 2026-08-09 12:00 |
17:57:31.15 |
+43:33:28.4 |
HIP 87944 |
9.62 |
| 2026-08-10 00:00 |
17:57:28.60 |
+43:33:01.6 |
HIP 87944 |
9.47 |
| 2026-08-10 12:00 |
17:57:26.07 |
+43:32:34.5 |
HIP 87944 |
9.36 |
| 2026-08-11 00:00 |
17:57:23.57 |
+43:32:07.3 |
HIP 87944 |
9.28 |
| 2026-08-11 12:00 |
17:57:21.09 |
+43:31:39.8 |
HIP 87944 |
9.25 |
| 2026-08-12 00:00 |
17:57:18.63 |
+43:31:12.2 |
HIP 87944 |
9.25 |
| 2026-08-12 12:00 |
17:57:16.20 |
+43:30:44.3 |
HIP 87944 |
9.29 |
| 2026-08-13 00:00 |
17:57:13.80 |
+43:30:16.2 |
HIP 87944 |
9.37 |
| 2026-08-13 12:00 |
17:57:11.42 |
+43:29:48.0 |
HIP 87944 |
9.48 |
| 2026-08-14 00:00 |
17:57:09.07 |
+43:29:19.5 |
HIP 87944 |
9.63 |
| 2026-08-14 12:00 |
17:57:06.75 |
+43:28:50.8 |
HIP 87944 |
9.82 |
| 2026-08-15 00:00 |
17:57:04.44 |
+43:28:22.0 |
HIP 87944 |
10.03 |
| 2026-08-15 12:00 |
17:57:02.17 |
+43:27:53.0 |
HIP 87944 |
10.28 |
| 2026-08-16 00:00 |
17:56:59.92 |
+43:27:23.7 |
HIP 87944 |
10.55 |
| 2026-08-16 12:00 |
17:56:57.70 |
+43:26:54.3 |
HIP 87944 |
10.85 |
| 2026-08-17 00:00 |
17:56:55.51 |
+43:26:24.7 |
HIP 87944 |
11.17 |
| 2026-08-17 12:00 |
17:56:53.34 |
+43:25:55.0 |
HIP 87944 |
11.52 |
| 2026-08-18 00:00 |
17:56:51.20 |
+43:25:25.0 |
HIP 87944 |
11.88 |
| 2026-08-18 12:00 |
17:56:49.08 |
+43:24:54.9 |
HIP 87944 |
12.26 |
| 2026-08-19 00:00 |
17:56:47.00 |
+43:24:24.6 |
HIP 87944 |
12.65 |