| 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) |
| 2026-06-01 00:00 |
04:21:20.79 |
-23:15:03.3 |
HIP 20208 |
33.69 |
| 2026-06-01 12:00 |
04:21:27.31 |
-23:15:01.3 |
HIP 20208 |
34.62 |
| 2026-06-02 00:00 |
04:21:33.83 |
-23:14:59.9 |
HIP 20208 |
35.59 |
| 2026-06-02 12:00 |
04:21:40.35 |
-23:14:59.0 |
HIP 20208 |
36.61 |
| 2026-06-03 00:00 |
04:21:46.86 |
-23:14:58.7 |
HIP 20208 |
37.66 |
| 2026-06-03 12:00 |
04:21:53.37 |
-23:14:58.9 |
HIP 20208 |
38.75 |
| 2026-06-04 00:00 |
04:21:59.87 |
-23:14:59.6 |
HIP 20208 |
39.87 |
| 2026-06-04 12:00 |
04:22:06.36 |
-23:15:00.9 |
HIP 20208 |
41.02 |
| 2026-06-05 00:00 |
04:22:12.85 |
-23:15:02.7 |
HIP 20208 |
42.19 |
| 2026-06-05 12:00 |
04:22:19.33 |
-23:15:05.0 |
HIP 20208 |
43.39 |
| 2026-06-06 00:00 |
04:22:25.80 |
-23:15:07.9 |
HIP 20208 |
44.61 |
| 2026-06-06 12:00 |
04:22:32.26 |
-23:15:11.4 |
HIP 20208 |
45.85 |
| 2026-06-07 00:00 |
04:22:38.72 |
-23:15:15.4 |
HIP 20208 |
47.11 |
| 2026-06-07 12:00 |
04:22:45.17 |
-23:15:19.9 |
HIP 20208 |
48.38 |
| 2026-06-08 00:00 |
04:22:51.61 |
-23:15:25.0 |
HIP 20208 |
49.67 |
| 2026-06-08 12:00 |
04:22:58.04 |
-23:15:30.6 |
HIP 20730 |
49.70 |
| 2026-06-09 00:00 |
04:23:04.46 |
-23:15:36.8 |
HIP 20730 |
48.25 |
| 2026-06-09 12:00 |
04:23:10.87 |
-23:15:43.5 |
HIP 20730 |
46.82 |
| 2026-06-10 00:00 |
04:23:17.27 |
-23:15:50.7 |
HIP 20730 |
45.39 |
| 2026-06-10 12:00 |
04:23:23.65 |
-23:15:58.5 |
HIP 20730 |
43.96 |
| 2026-06-11 00:00 |
04:23:30.03 |
-23:16:06.9 |
HIP 20730 |
42.55 |
| 2026-06-11 12:00 |
04:23:36.40 |
-23:16:15.8 |
HIP 20730 |
41.14 |
| 2026-06-12 00:00 |
04:23:42.75 |
-23:16:25.2 |
HIP 20730 |
39.74 |
| 2026-06-12 12:00 |
04:23:49.09 |
-23:16:35.2 |
HIP 20730 |
38.36 |
| 2026-06-13 00:00 |
04:23:55.42 |
-23:16:45.7 |
HIP 20730 |
36.98 |
| 2026-06-13 12:00 |
04:24:01.73 |
-23:16:56.8 |
HIP 20730 |
35.62 |
| 2026-06-14 00:00 |
04:24:08.03 |
-23:17:08.4 |
HIP 20730 |
34.27 |
| 2026-06-14 12:00 |
04:24:14.32 |
-23:17:20.5 |
HIP 20730 |
32.93 |
| 2026-06-15 00:00 |
04:24:20.59 |
-23:17:33.3 |
HIP 20730 |
31.61 |
| 2026-06-15 12:00 |
04:24:26.85 |
-23:17:46.5 |
HIP 20730 |
30.31 |
| 2026-06-16 00:00 |
04:24:33.09 |
-23:18:00.3 |
HIP 20730 |
29.03 |
| 2026-06-16 12:00 |
04:24:39.32 |
-23:18:14.6 |
HIP 20730 |
27.78 |
| 2026-06-17 00:00 |
04:24:45.52 |
-23:18:29.5 |
HIP 20730 |
26.55 |
| 2026-06-17 12:00 |
04:24:51.72 |
-23:18:45.0 |
HIP 20730 |
25.36 |
| 2026-06-18 00:00 |
04:24:57.89 |
-23:19:00.9 |
HIP 20730 |
24.19 |
| 2026-06-18 12:00 |
04:25:04.05 |
-23:19:17.4 |
HIP 20730 |
23.07 |
| 2026-06-19 00:00 |
04:25:10.19 |
-23:19:34.5 |
HIP 20730 |
22.00 |
| 2026-06-19 12:00 |
04:25:16.31 |
-23:19:52.1 |
HIP 20730 |
20.97 |
| 2026-06-20 00:00 |
04:25:22.41 |
-23:20:10.2 |
HIP 20730 |
20.01 |
| 2026-06-20 12:00 |
04:25:28.49 |
-23:20:28.8 |
HIP 20730 |
19.11 |
| 2026-06-21 00:00 |
04:25:34.55 |
-23:20:48.0 |
HIP 20730 |
18.29 |
| 2026-06-21 12:00 |
04:25:40.60 |
-23:21:07.8 |
HIP 20730 |
17.56 |
| 2026-06-22 00:00 |
04:25:46.62 |
-23:21:28.0 |
HIP 20730 |
16.93 |