| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
18:05:26.51 |
+43:51:07.9 |
HIP 88722 |
28.14 |
| 2026-06-03 00:00 |
18:05:22.89 |
+43:51:21.1 |
HIP 88722 |
28.67 |
| 2026-06-03 12:00 |
18:05:19.27 |
+43:51:34.0 |
HIP 88722 |
29.20 |
| 2026-06-04 00:00 |
18:05:15.63 |
+43:51:46.6 |
HIP 88722 |
29.74 |
| 2026-06-04 12:00 |
18:05:11.99 |
+43:51:58.8 |
HIP 88722 |
30.28 |
| 2026-06-05 00:00 |
18:05:08.34 |
+43:52:10.8 |
HIP 88722 |
30.82 |
| 2026-06-05 12:00 |
18:05:04.67 |
+43:52:22.4 |
HIP 88321 |
31.13 |
| 2026-06-06 00:00 |
18:05:01.00 |
+43:52:33.8 |
HIP 88321 |
30.45 |
| 2026-06-06 12:00 |
18:04:57.31 |
+43:52:44.8 |
HIP 88321 |
29.76 |
| 2026-06-07 00:00 |
18:04:53.62 |
+43:52:55.5 |
HIP 88321 |
29.07 |
| 2026-06-07 12:00 |
18:04:49.92 |
+43:53:05.9 |
HIP 88321 |
28.38 |
| 2026-06-08 00:00 |
18:04:46.21 |
+43:53:16.0 |
HIP 88321 |
27.69 |
| 2026-06-08 12:00 |
18:04:42.50 |
+43:53:25.7 |
HIP 88321 |
27.00 |
| 2026-06-09 00:00 |
18:04:38.77 |
+43:53:35.2 |
HIP 88321 |
26.32 |
| 2026-06-09 12:00 |
18:04:35.04 |
+43:53:44.3 |
HIP 88321 |
25.63 |
| 2026-06-10 00:00 |
18:04:31.30 |
+43:53:53.1 |
HIP 88321 |
24.94 |
| 2026-06-10 12:00 |
18:04:27.55 |
+43:54:01.6 |
HIP 88321 |
24.25 |
| 2026-06-11 00:00 |
18:04:23.80 |
+43:54:09.8 |
HIP 88321 |
23.56 |
| 2026-06-11 12:00 |
18:04:20.04 |
+43:54:17.7 |
HIP 88321 |
22.87 |
| 2026-06-12 00:00 |
18:04:16.27 |
+43:54:25.2 |
HIP 88321 |
22.18 |
| 2026-06-12 12:00 |
18:04:12.50 |
+43:54:32.5 |
HIP 88321 |
21.49 |
| 2026-06-13 00:00 |
18:04:08.72 |
+43:54:39.4 |
HIP 88321 |
20.80 |
| 2026-06-13 12:00 |
18:04:04.94 |
+43:54:45.9 |
HIP 88321 |
20.11 |
| 2026-06-14 00:00 |
18:04:01.15 |
+43:54:52.2 |
HIP 88321 |
19.42 |
| 2026-06-14 12:00 |
18:03:57.35 |
+43:54:58.1 |
HIP 88321 |
18.73 |
| 2026-06-15 00:00 |
18:03:53.56 |
+43:55:03.7 |
HIP 88321 |
18.04 |
| 2026-06-15 12:00 |
18:03:49.76 |
+43:55:09.0 |
HIP 88321 |
17.36 |
| 2026-06-16 00:00 |
18:03:45.95 |
+43:55:14.0 |
HIP 88321 |
16.67 |
| 2026-06-16 12:00 |
18:03:42.14 |
+43:55:18.6 |
HIP 88321 |
15.98 |
| 2026-06-17 00:00 |
18:03:38.33 |
+43:55:22.9 |
HIP 88321 |
15.30 |
| 2026-06-17 12:00 |
18:03:34.52 |
+43:55:26.9 |
HIP 88321 |
14.62 |
| 2026-06-18 00:00 |
18:03:30.70 |
+43:55:30.6 |
HIP 88321 |
13.93 |
| 2026-06-18 12:00 |
18:03:26.88 |
+43:55:33.9 |
HIP 88321 |
13.25 |
| 2026-06-19 00:00 |
18:03:23.06 |
+43:55:36.9 |
HIP 88321 |
12.58 |
| 2026-06-19 12:00 |
18:03:19.24 |
+43:55:39.6 |
HIP 88321 |
11.90 |
| 2026-06-20 00:00 |
18:03:15.42 |
+43:55:42.0 |
HIP 88321 |
11.23 |
| 2026-06-20 12:00 |
18:03:11.59 |
+43:55:44.0 |
HIP 88321 |
10.56 |
| 2026-06-21 00:00 |
18:03:07.77 |
+43:55:45.7 |
HIP 88321 |
9.90 |
| 2026-06-21 12:00 |
18:03:03.94 |
+43:55:47.1 |
HIP 88321 |
9.24 |
| 2026-06-22 00:00 |
18:03:00.12 |
+43:55:48.2 |
HIP 88321 |
8.59 |