| Parameter |
Value |
| Designation |
C/2020 F8 (SWAN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-05-27T13:06:40.423680Z |
| Orbit solution date (soln_date, UTC) |
2025-01-13T11:42:04Z |
| Obs used |
376 |
| NEO |
- |
| M1 |
11.600 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-04-24.0000000 |
| e |
0.99984071 |
| q (au) |
0.430317 |
| a (au) |
2701.498705 |
| i (deg) |
110.796078 |
| Ω (om, deg) |
260.028658 |
| ω (w, deg) |
68.198142 |
| M (ma, deg) |
359.999765 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.818 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.818 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
1.000 |
| 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 |
| 2019-10-22 |
2020-05-04 |
+12.2165 |
-0.587 |
| 2020-05-04 |
2020-05-26 |
-11.0290 |
-2.641 |
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 |
04:33:08.40 |
-26:12:56.7 |
HIP 21215 |
1.53 |
| 2026-09-20 12:00 |
04:33:06.02 |
-26:14:11.9 |
HIP 21215 |
0.79 |
| 2026-09-21 00:00 |
04:33:03.58 |
-26:15:27.0 |
HIP 21215 |
1.61 |
| 2026-09-21 12:00 |
04:33:01.09 |
-26:16:42.0 |
HIP 21215 |
2.88 |
| 2026-09-22 00:00 |
04:32:58.53 |
-26:17:56.9 |
HIP 21215 |
4.22 |
| 2026-09-22 12:00 |
04:32:55.92 |
-26:19:11.7 |
HIP 21215 |
5.57 |
| 2026-09-23 00:00 |
04:32:53.24 |
-26:20:26.3 |
HIP 21215 |
6.94 |
| 2026-09-23 12:00 |
04:32:50.51 |
-26:21:40.9 |
HIP 21215 |
8.31 |
| 2026-09-24 00:00 |
04:32:47.72 |
-26:22:55.3 |
HIP 21215 |
9.69 |
| 2026-09-24 12:00 |
04:32:44.87 |
-26:24:09.6 |
HIP 21215 |
11.08 |
| 2026-09-25 00:00 |
04:32:41.97 |
-26:25:23.8 |
HIP 21215 |
12.47 |
| 2026-09-25 12:00 |
04:32:39.01 |
-26:26:37.8 |
HIP 21215 |
13.86 |
| 2026-09-26 00:00 |
04:32:35.98 |
-26:27:51.7 |
HIP 21215 |
15.26 |
| 2026-09-26 12:00 |
04:32:32.91 |
-26:29:05.4 |
HIP 21215 |
16.66 |
| 2026-09-27 00:00 |
04:32:29.77 |
-26:30:19.0 |
HIP 21215 |
18.06 |
| 2026-09-27 12:00 |
04:32:26.58 |
-26:31:32.4 |
HIP 21215 |
19.47 |
| 2026-09-28 00:00 |
04:32:23.33 |
-26:32:45.7 |
HIP 21215 |
20.89 |
| 2026-09-28 12:00 |
04:32:20.02 |
-26:33:58.7 |
HIP 21215 |
22.30 |
| 2026-09-29 00:00 |
04:32:16.66 |
-26:35:11.6 |
HIP 21215 |
23.73 |
| 2026-09-29 12:00 |
04:32:13.24 |
-26:36:24.4 |
HIP 21215 |
25.15 |
| 2026-09-30 00:00 |
04:32:09.77 |
-26:37:36.9 |
HIP 21215 |
26.58 |
| 2026-09-30 12:00 |
04:32:06.24 |
-26:38:49.2 |
HIP 21215 |
28.01 |
| 2026-10-01 00:00 |
04:32:02.65 |
-26:40:01.4 |
HIP 21215 |
29.45 |
| 2026-10-01 12:00 |
04:31:59.00 |
-26:41:13.3 |
HIP 21215 |
30.88 |
| 2026-10-02 00:00 |
04:31:55.30 |
-26:42:25.0 |
HIP 21215 |
32.33 |
| 2026-10-02 12:00 |
04:31:51.55 |
-26:43:36.5 |
HIP 21215 |
33.77 |
| 2026-10-03 00:00 |
04:31:47.74 |
-26:44:47.8 |
HIP 21215 |
35.22 |
| 2026-10-03 12:00 |
04:31:43.87 |
-26:45:58.8 |
HIP 21215 |
36.68 |
| 2026-10-04 00:00 |
04:31:39.95 |
-26:47:09.7 |
HIP 21215 |
38.13 |
| 2026-10-04 12:00 |
04:31:35.98 |
-26:48:20.2 |
HIP 21215 |
39.59 |
| 2026-10-05 00:00 |
04:31:31.95 |
-26:49:30.6 |
HIP 21215 |
41.06 |
| 2026-10-05 12:00 |
04:31:27.86 |
-26:50:40.6 |
HIP 21215 |
42.52 |
| 2026-10-06 00:00 |
04:31:23.72 |
-26:51:50.5 |
HIP 20953 |
43.15 |
| 2026-10-06 12:00 |
04:31:19.53 |
-26:53:00.0 |
HIP 20953 |
43.58 |
| 2026-10-07 00:00 |
04:31:15.29 |
-26:54:09.3 |
HIP 20858 |
43.29 |
| 2026-10-07 12:00 |
04:31:10.99 |
-26:55:18.3 |
HIP 20858 |
42.78 |
| 2026-10-08 00:00 |
04:31:06.63 |
-26:56:27.0 |
HIP 20858 |
42.31 |
| 2026-10-08 12:00 |
04:31:02.23 |
-26:57:35.5 |
HIP 20858 |
41.87 |
| 2026-10-09 00:00 |
04:30:57.77 |
-26:58:43.6 |
HIP 20858 |
41.47 |
| 2026-10-09 12:00 |
04:30:53.26 |
-26:59:51.5 |
HIP 20858 |
41.11 |
| 2026-10-10 00:00 |
04:30:48.70 |
-27:00:59.0 |
HIP 20858 |
40.79 |
| 2026-10-10 12:00 |
04:30:44.08 |
-27:02:06.2 |
HIP 20858 |
40.51 |
| 2026-10-11 00:00 |
04:30:39.42 |
-27:03:13.1 |
HIP 20858 |
40.28 |