C/2020 F3 (NEOWISE)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2020 F3 (NEOWISE) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2020-07-03T16:17:36.787200Z |
| Orbit solution date (soln_date, UTC) | 2024-07-30T14:57:24Z |
| Obs used | 1315 |
| NEO | - |
| M1 | 12.100 |
| K1 | 12.250 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2020-07-06.0000000 |
| e | 0.99917803 |
| q (au) | 0.294651 |
| a (au) | 358.467957 |
| i (deg) | 128.937503 |
| Ω (om, deg) | 61.010428 |
| ω (w, deg) | 37.278658 |
| M (ma, deg) | 0.000337 |
Magnitude
Scatter + Global Linear
$$ M_a = (8.528 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.528 |
| 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 |
|---|---|---|---|
| 2020-03-27 | 2020-04-22 | +19.1066 | -3.750 |
| 2020-04-22 | 2020-05-07 | +13.0268 | -2.825 |
| 2020-05-07 | 2020-07-03 | +0.2884 | -1.471 |
| 2020-07-04 | 2020-07-17 | +2.2425 | +1.195 |
| 2020-07-17 | 2020-08-25 | -6.5755 | -0.804 |
| 2020-08-25 | 2026-08-22 | -15.7142 | +0.853 |
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 | 14:21:00.97 | -32:08:44.2 | HIP 70126 | 19.18 |
| 2026-09-20 12:00 | 14:21:06.03 | -32:08:50.2 | HIP 70126 | 19.37 |
| 2026-09-21 00:00 | 14:21:11.13 | -32:08:56.5 | HIP 70126 | 19.62 |
| 2026-09-21 12:00 | 14:21:16.27 | -32:09:03.2 | HIP 70126 | 19.94 |
| 2026-09-22 00:00 | 14:21:21.43 | -32:09:10.2 | HIP 70126 | 20.32 |
| 2026-09-22 12:00 | 14:21:26.63 | -32:09:17.6 | HIP 70126 | 20.76 |
| 2026-09-23 00:00 | 14:21:31.86 | -32:09:25.2 | HIP 70126 | 21.25 |
| 2026-09-23 12:00 | 14:21:37.12 | -32:09:33.2 | HIP 70126 | 21.80 |
| 2026-09-24 00:00 | 14:21:42.42 | -32:09:41.4 | HIP 70126 | 22.40 |
| 2026-09-24 12:00 | 14:21:47.74 | -32:09:50.0 | HIP 70126 | 23.04 |
| 2026-09-25 00:00 | 14:21:53.09 | -32:09:58.9 | HIP 70126 | 23.73 |
| 2026-09-25 12:00 | 14:21:58.48 | -32:10:08.2 | HIP 70126 | 24.46 |
| 2026-09-26 00:00 | 14:22:03.89 | -32:10:17.7 | HIP 70126 | 25.24 |
| 2026-09-26 12:00 | 14:22:09.34 | -32:10:27.6 | HIP 70126 | 26.04 |
| 2026-09-27 00:00 | 14:22:14.81 | -32:10:37.7 | HIP 70126 | 26.89 |
| 2026-09-27 12:00 | 14:22:20.31 | -32:10:48.2 | HIP 70126 | 27.76 |
| 2026-09-28 00:00 | 14:22:25.84 | -32:10:59.0 | HIP 70257 | 28.18 |
| 2026-09-28 12:00 | 14:22:31.39 | -32:11:10.1 | HIP 70257 | 28.34 |
| 2026-09-29 00:00 | 14:22:36.98 | -32:11:21.5 | HIP 70257 | 28.56 |
| 2026-09-29 12:00 | 14:22:42.59 | -32:11:33.2 | HIP 70257 | 28.84 |
| 2026-09-30 00:00 | 14:22:48.23 | -32:11:45.3 | HIP 70257 | 29.16 |
| 2026-09-30 12:00 | 14:22:53.90 | -32:11:57.6 | HIP 70257 | 29.54 |
| 2026-10-01 00:00 | 14:22:59.59 | -32:12:10.2 | HIP 70495 | 29.32 |
| 2026-10-01 12:00 | 14:23:05.30 | -32:12:23.2 | HIP 70495 | 28.27 |
| 2026-10-02 00:00 | 14:23:11.05 | -32:12:36.4 | HIP 70495 | 27.24 |
| 2026-10-02 12:00 | 14:23:16.82 | -32:12:50.0 | HIP 70495 | 26.23 |
| 2026-10-03 00:00 | 14:23:22.61 | -32:13:03.8 | HIP 70495 | 25.23 |
| 2026-10-03 12:00 | 14:23:28.43 | -32:13:18.0 | HIP 70495 | 24.25 |
| 2026-10-04 00:00 | 14:23:34.27 | -32:13:32.4 | HIP 70495 | 23.30 |
| 2026-10-04 12:00 | 14:23:40.14 | -32:13:47.2 | HIP 70495 | 22.38 |
| 2026-10-05 00:00 | 14:23:46.02 | -32:14:02.2 | HIP 70495 | 21.49 |
| 2026-10-05 12:00 | 14:23:51.94 | -32:14:17.5 | HIP 70495 | 20.64 |
| 2026-10-06 00:00 | 14:23:57.87 | -32:14:33.2 | HIP 70495 | 19.84 |
| 2026-10-06 12:00 | 14:24:03.83 | -32:14:49.1 | HIP 70495 | 19.09 |
| 2026-10-07 00:00 | 14:24:09.81 | -32:15:05.3 | HIP 70495 | 18.40 |
| 2026-10-07 12:00 | 14:24:15.81 | -32:15:21.9 | HIP 70495 | 17.78 |
| 2026-10-08 00:00 | 14:24:21.83 | -32:15:38.7 | HIP 70495 | 17.23 |
| 2026-10-08 12:00 | 14:24:27.87 | -32:15:55.8 | HIP 70495 | 16.77 |
| 2026-10-09 00:00 | 14:24:33.93 | -32:16:13.2 | HIP 70495 | 16.41 |
| 2026-10-09 12:00 | 14:24:40.01 | -32:16:30.8 | HIP 70495 | 16.15 |
| 2026-10-10 00:00 | 14:24:46.11 | -32:16:48.8 | HIP 70495 | 16.00 |
| 2026-10-10 12:00 | 14:24:52.23 | -32:17:07.0 | HIP 70495 | 15.96 |
| 2026-10-11 00:00 | 14:24:58.37 | -32:17:25.6 | HIP 70495 | 16.03 |