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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 14:40:57.46 | -34:42:16.1 | HIP 71804 | 6.81 |
| 2026-03-26 12:00 | 14:40:50.68 | -34:42:15.2 | HIP 71804 | 7.70 |
| 2026-03-27 00:00 | 14:40:43.85 | -34:42:13.9 | HIP 71804 | 8.73 |
| 2026-03-27 12:00 | 14:40:36.99 | -34:42:12.2 | HIP 71804 | 9.86 |
| 2026-03-28 00:00 | 14:40:30.07 | -34:42:10.1 | HIP 71804 | 11.06 |
| 2026-03-28 12:00 | 14:40:23.12 | -34:42:07.6 | HIP 71804 | 12.31 |
| 2026-03-29 00:00 | 14:40:16.13 | -34:42:04.6 | HIP 71804 | 13.60 |
| 2026-03-29 12:00 | 14:40:09.09 | -34:42:01.3 | HIP 71642 | 12.41 |
| 2026-03-30 00:00 | 14:40:02.01 | -34:41:57.5 | HIP 71642 | 11.17 |
| 2026-03-30 12:00 | 14:39:54.89 | -34:41:53.3 | HIP 71642 | 10.00 |
| 2026-03-31 00:00 | 14:39:47.74 | -34:41:48.7 | HIP 71642 | 8.90 |
| 2026-03-31 12:00 | 14:39:40.54 | -34:41:43.7 | HIP 71642 | 7.93 |
| 2026-04-01 00:00 | 14:39:33.31 | -34:41:38.2 | HIP 71642 | 7.14 |
| 2026-04-01 12:00 | 14:39:26.03 | -34:41:32.4 | HIP 71642 | 6.60 |
| 2026-04-02 00:00 | 14:39:18.72 | -34:41:26.1 | HIP 71642 | 6.38 |
| 2026-04-02 12:00 | 14:39:11.38 | -34:41:19.4 | HIP 71642 | 6.51 |
| 2026-04-03 00:00 | 14:39:03.99 | -34:41:12.3 | HIP 71642 | 6.99 |
| 2026-04-03 12:00 | 14:38:56.58 | -34:41:04.8 | HIP 71642 | 7.75 |
| 2026-04-04 00:00 | 14:38:49.12 | -34:40:56.8 | HIP 71642 | 8.73 |
| 2026-04-04 12:00 | 14:38:41.64 | -34:40:48.5 | HIP 71642 | 9.86 |
| 2026-04-05 00:00 | 14:38:34.12 | -34:40:39.7 | HIP 71642 | 11.10 |
| 2026-04-05 12:00 | 14:38:26.56 | -34:40:30.5 | HIP 71642 | 12.42 |
| 2026-04-06 00:00 | 14:38:18.98 | -34:40:20.9 | HIP 71542 | 12.25 |
| 2026-04-06 12:00 | 14:38:11.36 | -34:40:10.9 | HIP 71542 | 11.62 |
| 2026-04-07 00:00 | 14:38:03.71 | -34:40:00.5 | HIP 71542 | 11.17 |
| 2026-04-07 12:00 | 14:37:56.03 | -34:39:49.7 | HIP 71542 | 10.93 |
| 2026-04-08 00:00 | 14:37:48.32 | -34:39:38.4 | HIP 71542 | 10.91 |
| 2026-04-08 12:00 | 14:37:40.58 | -34:39:26.8 | HIP 71542 | 11.12 |
| 2026-04-09 00:00 | 14:37:32.81 | -34:39:14.7 | HIP 71542 | 11.55 |
| 2026-04-09 12:00 | 14:37:25.02 | -34:39:02.2 | HIP 71542 | 12.17 |
| 2026-04-10 00:00 | 14:37:17.19 | -34:38:49.4 | HIP 71542 | 12.97 |
| 2026-04-10 12:00 | 14:37:09.34 | -34:38:36.1 | HIP 71542 | 13.91 |
| 2026-04-11 00:00 | 14:37:01.47 | -34:38:22.4 | HIP 71542 | 14.97 |
| 2026-04-11 12:00 | 14:36:53.56 | -34:38:08.3 | HIP 71542 | 16.12 |
| 2026-04-12 00:00 | 14:36:45.64 | -34:37:53.7 | HIP 71384 | 15.82 |
| 2026-04-12 12:00 | 14:36:37.69 | -34:37:38.8 | HIP 71384 | 14.89 |
| 2026-04-13 00:00 | 14:36:29.71 | -34:37:23.5 | HIP 71384 | 14.10 |
| 2026-04-13 12:00 | 14:36:21.72 | -34:37:07.8 | HIP 71384 | 13.46 |
| 2026-04-14 00:00 | 14:36:13.70 | -34:36:51.7 | HIP 71384 | 13.02 |
| 2026-04-14 12:00 | 14:36:05.66 | -34:36:35.1 | HIP 71384 | 12.78 |
| 2026-04-15 00:00 | 14:35:57.60 | -34:36:18.2 | HIP 71384 | 12.77 |
| 2026-04-15 12:00 | 14:35:49.52 | -34:36:00.9 | HIP 71384 | 12.98 |
| 2026-04-16 00:00 | 14:35:41.42 | -34:35:43.2 | HIP 71384 | 13.41 |