| 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) |
| 2026-05-12 00:00 |
18:07:48.06 |
+43:37:06.5 |
HIP 88788 |
10.02 |
| 2026-05-12 12:00 |
18:07:45.15 |
+43:37:31.8 |
HIP 88788 |
10.25 |
| 2026-05-13 00:00 |
18:07:42.22 |
+43:37:56.8 |
HIP 88788 |
10.51 |
| 2026-05-13 12:00 |
18:07:39.27 |
+43:38:21.5 |
HIP 88788 |
10.81 |
| 2026-05-14 00:00 |
18:07:36.29 |
+43:38:46.1 |
HIP 88788 |
11.13 |
| 2026-05-14 12:00 |
18:07:33.30 |
+43:39:10.3 |
HIP 88788 |
11.48 |
| 2026-05-15 00:00 |
18:07:30.28 |
+43:39:34.3 |
HIP 88788 |
11.85 |
| 2026-05-15 12:00 |
18:07:27.25 |
+43:39:58.1 |
HIP 88788 |
12.25 |
| 2026-05-16 00:00 |
18:07:24.19 |
+43:40:21.6 |
HIP 88788 |
12.66 |
| 2026-05-16 12:00 |
18:07:21.12 |
+43:40:44.8 |
HIP 88788 |
13.10 |
| 2026-05-17 00:00 |
18:07:18.02 |
+43:41:07.8 |
HIP 88788 |
13.55 |
| 2026-05-17 12:00 |
18:07:14.91 |
+43:41:30.5 |
HIP 88788 |
14.01 |
| 2026-05-18 00:00 |
18:07:11.78 |
+43:41:52.9 |
HIP 88788 |
14.49 |
| 2026-05-18 12:00 |
18:07:08.62 |
+43:42:15.0 |
HIP 88788 |
14.98 |
| 2026-05-19 00:00 |
18:07:05.45 |
+43:42:36.9 |
HIP 88788 |
15.48 |
| 2026-05-19 12:00 |
18:07:02.26 |
+43:42:58.5 |
HIP 88788 |
15.99 |
| 2026-05-20 00:00 |
18:06:59.05 |
+43:43:19.9 |
HIP 88722 |
16.35 |
| 2026-05-20 12:00 |
18:06:55.83 |
+43:43:41.0 |
HIP 88722 |
16.64 |
| 2026-05-21 00:00 |
18:06:52.59 |
+43:44:01.7 |
HIP 88722 |
16.94 |
| 2026-05-21 12:00 |
18:06:49.32 |
+43:44:22.3 |
HIP 88722 |
17.26 |
| 2026-05-22 00:00 |
18:06:46.05 |
+43:44:42.5 |
HIP 88722 |
17.59 |
| 2026-05-22 12:00 |
18:06:42.75 |
+43:45:02.4 |
HIP 88722 |
17.95 |
| 2026-05-23 00:00 |
18:06:39.44 |
+43:45:22.1 |
HIP 88722 |
18.31 |
| 2026-05-23 12:00 |
18:06:36.11 |
+43:45:41.5 |
HIP 88722 |
18.69 |
| 2026-05-24 00:00 |
18:06:32.77 |
+43:46:00.6 |
HIP 88722 |
19.08 |
| 2026-05-24 12:00 |
18:06:29.41 |
+43:46:19.4 |
HIP 88722 |
19.49 |
| 2026-05-25 00:00 |
18:06:26.03 |
+43:46:37.9 |
HIP 88722 |
19.90 |
| 2026-05-25 12:00 |
18:06:22.64 |
+43:46:56.2 |
HIP 88722 |
20.33 |
| 2026-05-26 00:00 |
18:06:19.23 |
+43:47:14.1 |
HIP 88722 |
20.76 |
| 2026-05-26 12:00 |
18:06:15.81 |
+43:47:31.8 |
HIP 88722 |
21.21 |
| 2026-05-27 00:00 |
18:06:12.38 |
+43:47:49.1 |
HIP 88722 |
21.66 |
| 2026-05-27 12:00 |
18:06:08.93 |
+43:48:06.2 |
HIP 88722 |
22.12 |
| 2026-05-28 00:00 |
18:06:05.46 |
+43:48:23.0 |
HIP 88722 |
22.59 |
| 2026-05-28 12:00 |
18:06:01.99 |
+43:48:39.5 |
HIP 88722 |
23.06 |
| 2026-05-29 00:00 |
18:05:58.50 |
+43:48:55.7 |
HIP 88722 |
23.55 |
| 2026-05-29 12:00 |
18:05:54.99 |
+43:49:11.6 |
HIP 88722 |
24.04 |
| 2026-05-30 00:00 |
18:05:51.47 |
+43:49:27.2 |
HIP 88722 |
24.53 |
| 2026-05-30 12:00 |
18:05:47.94 |
+43:49:42.5 |
HIP 88722 |
25.03 |
| 2026-05-31 00:00 |
18:05:44.40 |
+43:49:57.5 |
HIP 88722 |
25.54 |
| 2026-05-31 12:00 |
18:05:40.84 |
+43:50:12.2 |
HIP 88722 |
26.05 |
| 2026-06-01 00:00 |
18:05:37.28 |
+43:50:26.5 |
HIP 88722 |
26.56 |
| 2026-06-01 12:00 |
18:05:33.70 |
+43:50:40.6 |
HIP 88722 |
27.08 |
| 2026-06-02 00:00 |
18:05:30.11 |
+43:50:54.4 |
HIP 88722 |
27.61 |