| 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) |
| 2026-09-20 00:00 |
17:55:34.35 |
+42:48:01.2 |
HIP 87631 |
19.39 |
| 2026-09-20 12:00 |
17:55:34.21 |
+42:47:25.2 |
HIP 87631 |
19.09 |
| 2026-09-21 00:00 |
17:55:34.11 |
+42:46:49.1 |
HIP 87631 |
18.81 |
| 2026-09-21 12:00 |
17:55:34.04 |
+42:46:13.0 |
HIP 87631 |
18.55 |
| 2026-09-22 00:00 |
17:55:34.00 |
+42:45:36.9 |
HIP 87631 |
18.31 |
| 2026-09-22 12:00 |
17:55:33.99 |
+42:45:00.8 |
HIP 87631 |
18.10 |
| 2026-09-23 00:00 |
17:55:34.01 |
+42:44:24.7 |
HIP 87631 |
17.91 |
| 2026-09-23 12:00 |
17:55:34.06 |
+42:43:48.7 |
HIP 87631 |
17.74 |
| 2026-09-24 00:00 |
17:55:34.15 |
+42:43:12.6 |
HIP 87631 |
17.60 |
| 2026-09-24 12:00 |
17:55:34.26 |
+42:42:36.6 |
HIP 87631 |
17.48 |
| 2026-09-25 00:00 |
17:55:34.41 |
+42:42:00.6 |
HIP 87631 |
17.39 |
| 2026-09-25 12:00 |
17:55:34.58 |
+42:41:24.6 |
HIP 87631 |
17.32 |
| 2026-09-26 00:00 |
17:55:34.79 |
+42:40:48.7 |
HIP 87631 |
17.28 |
| 2026-09-26 12:00 |
17:55:35.03 |
+42:40:12.7 |
HIP 87631 |
17.27 |
| 2026-09-27 00:00 |
17:55:35.30 |
+42:39:36.8 |
HIP 87631 |
17.28 |
| 2026-09-27 12:00 |
17:55:35.60 |
+42:39:01.0 |
HIP 87631 |
17.32 |
| 2026-09-28 00:00 |
17:55:35.94 |
+42:38:25.1 |
HIP 87631 |
17.39 |
| 2026-09-28 12:00 |
17:55:36.30 |
+42:37:49.3 |
HIP 87631 |
17.48 |
| 2026-09-29 00:00 |
17:55:36.69 |
+42:37:13.6 |
HIP 87631 |
17.60 |
| 2026-09-29 12:00 |
17:55:37.11 |
+42:36:37.9 |
HIP 87631 |
17.74 |
| 2026-09-30 00:00 |
17:55:37.57 |
+42:36:02.2 |
HIP 87631 |
17.91 |
| 2026-09-30 12:00 |
17:55:38.06 |
+42:35:26.6 |
HIP 87631 |
18.10 |
| 2026-10-01 00:00 |
17:55:38.57 |
+42:34:51.0 |
HIP 87631 |
18.31 |
| 2026-10-01 12:00 |
17:55:39.12 |
+42:34:15.5 |
HIP 87631 |
18.55 |
| 2026-10-02 00:00 |
17:55:39.69 |
+42:33:40.0 |
HIP 87631 |
18.81 |
| 2026-10-02 12:00 |
17:55:40.30 |
+42:33:04.6 |
HIP 87631 |
19.09 |
| 2026-10-03 00:00 |
17:55:40.94 |
+42:32:29.2 |
HIP 87631 |
19.38 |
| 2026-10-03 12:00 |
17:55:41.61 |
+42:31:54.0 |
HIP 87631 |
19.70 |
| 2026-10-04 00:00 |
17:55:42.31 |
+42:31:18.7 |
HIP 87631 |
20.03 |
| 2026-10-04 12:00 |
17:55:43.04 |
+42:30:43.6 |
HIP 87631 |
20.39 |
| 2026-10-05 00:00 |
17:55:43.80 |
+42:30:08.5 |
HIP 87631 |
20.75 |
| 2026-10-05 12:00 |
17:55:44.59 |
+42:29:33.5 |
HIP 87631 |
21.14 |
| 2026-10-06 00:00 |
17:55:45.41 |
+42:28:58.5 |
HIP 87631 |
21.53 |
| 2026-10-06 12:00 |
17:55:46.26 |
+42:28:23.7 |
HIP 87631 |
21.94 |
| 2026-10-07 00:00 |
17:55:47.14 |
+42:27:48.9 |
HIP 87631 |
22.37 |
| 2026-10-07 12:00 |
17:55:48.05 |
+42:27:14.2 |
HIP 87631 |
22.80 |
| 2026-10-08 00:00 |
17:55:48.99 |
+42:26:39.6 |
HIP 87631 |
23.25 |
| 2026-10-08 12:00 |
17:55:49.96 |
+42:26:05.1 |
HIP 87631 |
23.71 |
| 2026-10-09 00:00 |
17:55:50.96 |
+42:25:30.7 |
HIP 87631 |
24.18 |
| 2026-10-09 12:00 |
17:55:51.99 |
+42:24:56.4 |
HIP 87631 |
24.65 |
| 2026-10-10 00:00 |
17:55:53.05 |
+42:24:22.1 |
HIP 87631 |
25.14 |
| 2026-10-10 12:00 |
17:55:54.14 |
+42:23:48.0 |
HIP 87631 |
25.64 |
| 2026-10-11 00:00 |
17:55:55.25 |
+42:23:14.0 |
HIP 87631 |
26.14 |