378P/McNaught
Metadata
| Parameter | Value |
|---|---|
| Designation | 378P/McNaught |
| Type | P |
| Perihelion (tp_cal, UTC) | 2020-10-21T12:01:27.851520Z |
| Orbit solution date (soln_date, UTC) | 2026-01-13T08:12:54Z |
| Obs used | 828 |
| NEO | - |
| M1 | 12.200 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2019-03-10T03:16:12.864000Z |
| Discovery magnitude (MPC) | 21.90 G |
| Discovery observatory (MPC) | J04 · ESA Optical Ground Station, Tenerife |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2020-05-16.0000000 |
| e | 0.46883776 |
| q (au) | 3.380503 |
| a (au) | 6.364351 |
| i (deg) | 19.108649 |
| Ω (om, deg) | 94.516291 |
| ω (w, deg) | 194.158503 |
| M (ma, deg) | 350.270176 |
Magnitude
Scatter + Global Linear
$$ M_a = (15.990 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 15.990 |
| n | 2.000 |
| gf | 1.000 |
| gb | -0.828 |
| k | 0.800 |
| 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 |
|---|---|---|---|
| 2019-02-17 | 2020-04-05 | +16.4009 | -8.371 |
| 2021-04-03 | 2021-09-29 | -16.9913 | +11.467 |
| 2021-09-29 | 2022-12-16 | -7.8113 | +5.383 |
| 2022-12-16 | 2023-12-10 | +7.1275 | -6.004 |
| 2023-12-10 | 2026-01-12 | +4.0394 | -3.670 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Finding Chart
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 06:04:12.88 | +21:20:42.9 | HIP 28785 | 6.67 |
| 2026-07-29 12:00 | 06:04:26.73 | +21:20:53.1 | HIP 28785 | 3.94 |
| 2026-07-30 00:00 | 06:04:40.52 | +21:21:03.2 | HIP 28785 | 2.71 |
| 2026-07-30 12:00 | 06:04:54.26 | +21:21:13.2 | HIP 28785 | 4.45 |
| 2026-07-31 00:00 | 06:05:07.95 | +21:21:23.1 | HIP 28843 | 2.85 |
| 2026-07-31 12:00 | 06:05:21.58 | +21:21:32.9 | HIP 28843 | 1.95 |
| 2026-08-01 00:00 | 06:05:35.16 | +21:21:42.7 | HIP 28843 | 4.43 |
| 2026-08-01 12:00 | 06:05:48.69 | +21:21:52.3 | HIP 28843 | 7.44 |
| 2026-08-02 00:00 | 06:06:02.17 | +21:22:01.8 | HIP 28843 | 10.52 |
| 2026-08-02 12:00 | 06:06:15.59 | +21:22:11.2 | HIP 28843 | 13.61 |
| 2026-08-03 00:00 | 06:06:28.95 | +21:22:20.6 | HIP 28843 | 16.71 |
| 2026-08-03 12:00 | 06:06:42.26 | +21:22:29.8 | HIP 29077 | 19.26 |
| 2026-08-04 00:00 | 06:06:55.51 | +21:22:39.0 | HIP 29077 | 16.34 |
| 2026-08-04 12:00 | 06:07:08.71 | +21:22:48.1 | HIP 29077 | 13.50 |
| 2026-08-05 00:00 | 06:07:21.85 | +21:22:57.1 | HIP 29077 | 10.79 |
| 2026-08-05 12:00 | 06:07:34.93 | +21:23:06.0 | HIP 29077 | 8.36 |
| 2026-08-06 00:00 | 06:07:47.95 | +21:23:14.8 | HIP 29077 | 6.47 |
| 2026-08-06 12:00 | 06:08:00.91 | +21:23:23.5 | HIP 29077 | 5.68 |
| 2026-08-07 00:00 | 06:08:13.81 | +21:23:32.2 | HIP 29077 | 6.39 |
| 2026-08-07 12:00 | 06:08:26.65 | +21:23:40.8 | HIP 29077 | 8.20 |
| 2026-08-08 00:00 | 06:08:39.42 | +21:23:49.3 | HIP 29077 | 10.56 |
| 2026-08-08 12:00 | 06:08:52.14 | +21:23:57.7 | HIP 29077 | 13.15 |
| 2026-08-09 00:00 | 06:09:04.79 | +21:24:06.1 | HIP 29077 | 15.86 |
| 2026-08-09 12:00 | 06:09:17.38 | +21:24:14.3 | HIP 29077 | 18.63 |
| 2026-08-10 00:00 | 06:09:29.90 | +21:24:22.6 | HIP 29077 | 21.43 |
| 2026-08-10 12:00 | 06:09:42.36 | +21:24:30.7 | HIP 29360 | 24.14 |
| 2026-08-11 00:00 | 06:09:54.75 | +21:24:38.8 | HIP 29360 | 21.45 |
| 2026-08-11 12:00 | 06:10:07.08 | +21:24:46.8 | HIP 29360 | 18.83 |
| 2026-08-12 00:00 | 06:10:19.34 | +21:24:54.7 | HIP 29360 | 16.32 |
| 2026-08-12 12:00 | 06:10:31.53 | +21:25:02.6 | HIP 29360 | 13.94 |
| 2026-08-13 00:00 | 06:10:43.65 | +21:25:10.4 | HIP 29360 | 11.79 |
| 2026-08-13 12:00 | 06:10:55.71 | +21:25:18.1 | HIP 29360 | 9.99 |
| 2026-08-14 00:00 | 06:11:07.69 | +21:25:25.8 | HIP 29360 | 8.74 |
| 2026-08-14 12:00 | 06:11:19.60 | +21:25:33.4 | HIP 29360 | 8.28 |
| 2026-08-15 00:00 | 06:11:31.45 | +21:25:41.0 | HIP 29360 | 8.72 |
| 2026-08-15 12:00 | 06:11:43.22 | +21:25:48.5 | HIP 29360 | 9.92 |
| 2026-08-16 00:00 | 06:11:54.91 | +21:25:56.0 | HIP 29360 | 11.65 |
| 2026-08-16 12:00 | 06:12:06.54 | +21:26:03.4 | HIP 29360 | 13.69 |
| 2026-08-17 00:00 | 06:12:18.09 | +21:26:10.8 | HIP 29492 | 13.35 |
| 2026-08-17 12:00 | 06:12:29.57 | +21:26:18.1 | HIP 29492 | 12.01 |
| 2026-08-18 00:00 | 06:12:40.97 | +21:26:25.4 | HIP 29492 | 11.18 |
| 2026-08-18 12:00 | 06:12:52.29 | +21:26:32.6 | HIP 29492 | 10.94 |
| 2026-08-19 00:00 | 06:13:03.55 | +21:26:39.8 | HIP 29492 | 11.32 |