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
$$ M_a = (8.535 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.535 |
| 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 | -3.757 |
| 2020-04-22 | 2020-05-07 | +13.0268 | -2.831 |
| 2020-05-07 | 2020-07-03 | +0.2884 | -1.478 |
| 2020-07-04 | 2020-07-17 | +2.2790 | +1.205 |
| 2020-07-17 | 2023-04-14 | -6.6559 | -0.824 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 14:16:18.90 | -32:29:40.7 | HIP 69717 | 25.94 |
| 2026-07-29 12:00 | 14:16:18.72 | -32:29:11.9 | HIP 69717 | 26.41 |
| 2026-07-30 00:00 | 14:16:18.60 | -32:28:43.5 | HIP 69717 | 26.89 |
| 2026-07-30 12:00 | 14:16:18.53 | -32:28:15.3 | HIP 69717 | 27.36 |
| 2026-07-31 00:00 | 14:16:18.53 | -32:27:47.4 | HIP 69717 | 27.82 |
| 2026-07-31 12:00 | 14:16:18.59 | -32:27:19.8 | HIP 69717 | 28.28 |
| 2026-08-01 00:00 | 14:16:18.71 | -32:26:52.5 | HIP 69717 | 28.74 |
| 2026-08-01 12:00 | 14:16:18.89 | -32:26:25.5 | HIP 69717 | 29.19 |
| 2026-08-02 00:00 | 14:16:19.13 | -32:25:58.8 | HIP 69717 | 29.63 |
| 2026-08-02 12:00 | 14:16:19.42 | -32:25:32.4 | HIP 69717 | 30.08 |
| 2026-08-03 00:00 | 14:16:19.78 | -32:25:06.3 | HIP 69717 | 30.51 |
| 2026-08-03 12:00 | 14:16:20.20 | -32:24:40.5 | HIP 69939 | 30.48 |
| 2026-08-04 00:00 | 14:16:20.68 | -32:24:15.0 | HIP 69939 | 30.40 |
| 2026-08-04 12:00 | 14:16:21.21 | -32:23:49.7 | HIP 69939 | 30.31 |
| 2026-08-05 00:00 | 14:16:21.81 | -32:23:24.8 | HIP 69939 | 30.21 |
| 2026-08-05 12:00 | 14:16:22.46 | -32:23:00.2 | HIP 69939 | 30.11 |
| 2026-08-06 00:00 | 14:16:23.18 | -32:22:35.9 | HIP 69939 | 30.00 |
| 2026-08-06 12:00 | 14:16:23.95 | -32:22:11.9 | HIP 69939 | 29.88 |
| 2026-08-07 00:00 | 14:16:24.78 | -32:21:48.3 | HIP 69939 | 29.75 |
| 2026-08-07 12:00 | 14:16:25.67 | -32:21:24.9 | HIP 69939 | 29.62 |
| 2026-08-08 00:00 | 14:16:26.62 | -32:21:01.8 | HIP 69939 | 29.48 |
| 2026-08-08 12:00 | 14:16:27.62 | -32:20:39.1 | HIP 69939 | 29.33 |
| 2026-08-09 00:00 | 14:16:28.69 | -32:20:16.7 | HIP 69939 | 29.17 |
| 2026-08-09 12:00 | 14:16:29.81 | -32:19:54.6 | HIP 69939 | 29.01 |
| 2026-08-10 00:00 | 14:16:30.99 | -32:19:32.8 | HIP 69939 | 28.84 |
| 2026-08-10 12:00 | 14:16:32.23 | -32:19:11.3 | HIP 69939 | 28.67 |
| 2026-08-11 00:00 | 14:16:33.53 | -32:18:50.1 | HIP 69939 | 28.48 |
| 2026-08-11 12:00 | 14:16:34.88 | -32:18:29.3 | HIP 69939 | 28.29 |
| 2026-08-12 00:00 | 14:16:36.29 | -32:18:08.8 | HIP 69939 | 28.09 |
| 2026-08-12 12:00 | 14:16:37.76 | -32:17:48.6 | HIP 69939 | 27.88 |
| 2026-08-13 00:00 | 14:16:39.28 | -32:17:28.8 | HIP 69939 | 27.67 |
| 2026-08-13 12:00 | 14:16:40.87 | -32:17:09.3 | HIP 69939 | 27.45 |
| 2026-08-14 00:00 | 14:16:42.50 | -32:16:50.1 | HIP 69939 | 27.22 |
| 2026-08-14 12:00 | 14:16:44.20 | -32:16:31.2 | HIP 69939 | 26.99 |
| 2026-08-15 00:00 | 14:16:45.95 | -32:16:12.7 | HIP 69939 | 26.75 |
| 2026-08-15 12:00 | 14:16:47.75 | -32:15:54.5 | HIP 69939 | 26.50 |
| 2026-08-16 00:00 | 14:16:49.61 | -32:15:36.6 | HIP 69939 | 26.25 |
| 2026-08-16 12:00 | 14:16:51.53 | -32:15:19.0 | HIP 69939 | 25.99 |
| 2026-08-17 00:00 | 14:16:53.50 | -32:15:01.8 | HIP 69939 | 25.72 |
| 2026-08-17 12:00 | 14:16:55.52 | -32:14:45.0 | HIP 69939 | 25.45 |
| 2026-08-18 00:00 | 14:16:57.60 | -32:14:28.4 | HIP 69939 | 25.18 |
| 2026-08-18 12:00 | 14:16:59.73 | -32:14:12.2 | HIP 69939 | 24.90 |
| 2026-08-19 00:00 | 14:17:01.92 | -32:13:56.3 | HIP 69939 | 24.61 |