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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 06:22:00.11 | +21:34:04.5 | HIP 30241 | 19.98 |
| 2026-09-20 12:00 | 06:22:05.23 | +21:34:12.3 | HIP 30241 | 20.37 |
| 2026-09-21 00:00 | 06:22:10.23 | +21:34:20.3 | HIP 30241 | 20.82 |
| 2026-09-21 12:00 | 06:22:15.11 | +21:34:28.2 | HIP 30241 | 21.31 |
| 2026-09-22 00:00 | 06:22:19.89 | +21:34:36.3 | HIP 30241 | 21.84 |
| 2026-09-22 12:00 | 06:22:24.55 | +21:34:44.4 | HIP 30241 | 22.41 |
| 2026-09-23 00:00 | 06:22:29.10 | +21:34:52.6 | HIP 30241 | 23.00 |
| 2026-09-23 12:00 | 06:22:33.53 | +21:35:00.8 | HIP 30241 | 23.62 |
| 2026-09-24 00:00 | 06:22:37.85 | +21:35:09.2 | HIP 30241 | 24.25 |
| 2026-09-24 12:00 | 06:22:42.06 | +21:35:17.6 | HIP 30241 | 24.89 |
| 2026-09-25 00:00 | 06:22:46.15 | +21:35:26.0 | HIP 30241 | 25.54 |
| 2026-09-25 12:00 | 06:22:50.13 | +21:35:34.6 | HIP 30241 | 26.20 |
| 2026-09-26 00:00 | 06:22:53.99 | +21:35:43.2 | HIP 30241 | 26.85 |
| 2026-09-26 12:00 | 06:22:57.74 | +21:35:51.9 | HIP 30241 | 27.51 |
| 2026-09-27 00:00 | 06:23:01.37 | +21:36:00.6 | HIP 30241 | 28.16 |
| 2026-09-27 12:00 | 06:23:04.88 | +21:36:09.5 | HIP 30241 | 28.80 |
| 2026-09-28 00:00 | 06:23:08.28 | +21:36:18.4 | HIP 30241 | 29.44 |
| 2026-09-28 12:00 | 06:23:11.55 | +21:36:27.4 | HIP 30241 | 30.06 |
| 2026-09-29 00:00 | 06:23:14.71 | +21:36:36.4 | HIP 30241 | 30.68 |
| 2026-09-29 12:00 | 06:23:17.76 | +21:36:45.6 | HIP 30241 | 31.28 |
| 2026-09-30 00:00 | 06:23:20.68 | +21:36:54.8 | HIP 30241 | 31.87 |
| 2026-09-30 12:00 | 06:23:23.49 | +21:37:04.2 | HIP 30588 | 32.40 |
| 2026-10-01 00:00 | 06:23:26.17 | +21:37:13.6 | HIP 30588 | 31.77 |
| 2026-10-01 12:00 | 06:23:28.74 | +21:37:23.1 | HIP 30588 | 31.17 |
| 2026-10-02 00:00 | 06:23:31.19 | +21:37:32.7 | HIP 30588 | 30.59 |
| 2026-10-02 12:00 | 06:23:33.51 | +21:37:42.3 | HIP 30588 | 30.05 |
| 2026-10-03 00:00 | 06:23:35.72 | +21:37:52.1 | HIP 30588 | 29.53 |
| 2026-10-03 12:00 | 06:23:37.80 | +21:38:01.9 | HIP 30588 | 29.04 |
| 2026-10-04 00:00 | 06:23:39.76 | +21:38:11.9 | HIP 30588 | 28.58 |
| 2026-10-04 12:00 | 06:23:41.60 | +21:38:21.9 | HIP 30588 | 28.15 |
| 2026-10-05 00:00 | 06:23:43.32 | +21:38:32.0 | HIP 30588 | 27.75 |
| 2026-10-05 12:00 | 06:23:44.91 | +21:38:42.2 | HIP 30588 | 27.38 |
| 2026-10-06 00:00 | 06:23:46.39 | +21:38:52.5 | HIP 30588 | 27.04 |
| 2026-10-06 12:00 | 06:23:47.73 | +21:39:02.9 | HIP 30588 | 26.72 |
| 2026-10-07 00:00 | 06:23:48.96 | +21:39:13.4 | HIP 30588 | 26.44 |
| 2026-10-07 12:00 | 06:23:50.06 | +21:39:24.0 | HIP 30588 | 26.19 |
| 2026-10-08 00:00 | 06:23:51.04 | +21:39:34.7 | HIP 30588 | 25.97 |
| 2026-10-08 12:00 | 06:23:51.89 | +21:39:45.5 | HIP 30588 | 25.78 |
| 2026-10-09 00:00 | 06:23:52.61 | +21:39:56.4 | HIP 30588 | 25.62 |
| 2026-10-09 12:00 | 06:23:53.22 | +21:40:07.5 | HIP 30588 | 25.49 |
| 2026-10-10 00:00 | 06:23:53.69 | +21:40:18.6 | HIP 30588 | 25.39 |
| 2026-10-10 12:00 | 06:23:54.04 | +21:40:29.8 | HIP 30588 | 25.32 |
| 2026-10-11 00:00 | 06:23:54.27 | +21:40:41.1 | HIP 30588 | 25.28 |