C/2023 P1 (Nishimura)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 P1 (Nishimura) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2023-09-17T15:23:38.446080Z |
| Orbit solution date (soln_date, UTC) | 2024-08-08T14:27:14Z |
| Obs used | 638 |
| NEO | - |
| M1 | 12.200 |
| K1 | 8.000 |
| PC | - |
| Discovery observation (MPC, UTC) | 2023-08-11T18:26:41.856000Z |
| Discovery magnitude (MPC) | 11.00 T |
| Discovery observatory (MPC) | 247 · Roving Observer |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2023-09-08.0000000 |
| e | 0.99610274 |
| q (au) | 0.225152 |
| a (au) | 57.771776 |
| i (deg) | 132.476418 |
| Ω (om, deg) | 66.834552 |
| ω (w, deg) | 116.297994 |
| M (ma, deg) | 359.978359 |
Magnitude
Scatter + Global Linear
$$ M_a = (10.942 + 5.266\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 10.942 |
| n | 5.266 |
| gf | 0.997 |
| gb | -0.921 |
| k | 0.944 |
| δ90 | 9.998 |
| 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 |
|---|---|---|---|
| 2023-01-19 | 2023-09-16 | +0.1403 | +0.148 |
| 2023-09-18 | 2024-05-28 | -0.5521 | -1.485 |
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 | 08:32:56.82 | -25:52:00.6 | HIP 41959 | 10.74 |
| 2026-07-29 12:00 | 08:33:07.06 | -25:52:26.6 | HIP 41959 | 9.91 |
| 2026-07-30 00:00 | 08:33:17.29 | -25:52:53.4 | HIP 41959 | 9.57 |
| 2026-07-30 12:00 | 08:33:27.52 | -25:53:21.0 | HIP 41959 | 9.79 |
| 2026-07-31 00:00 | 08:33:37.73 | -25:53:49.5 | HIP 41959 | 10.52 |
| 2026-07-31 12:00 | 08:33:47.94 | -25:54:18.7 | HIP 41959 | 11.68 |
| 2026-08-01 00:00 | 08:33:58.14 | -25:54:48.8 | HIP 41959 | 13.15 |
| 2026-08-01 12:00 | 08:34:08.32 | -25:55:19.7 | HIP 41959 | 14.83 |
| 2026-08-02 00:00 | 08:34:18.50 | -25:55:51.4 | HIP 41959 | 16.67 |
| 2026-08-02 12:00 | 08:34:28.67 | -25:56:23.9 | HIP 41959 | 18.62 |
| 2026-08-03 00:00 | 08:34:38.82 | -25:56:57.2 | HIP 41959 | 20.64 |
| 2026-08-03 12:00 | 08:34:48.96 | -25:57:31.3 | HIP 41959 | 22.72 |
| 2026-08-04 00:00 | 08:34:59.09 | -25:58:06.3 | HIP 41959 | 24.84 |
| 2026-08-04 12:00 | 08:35:09.20 | -25:58:42.0 | HIP 41959 | 27.00 |
| 2026-08-05 00:00 | 08:35:19.30 | -25:59:18.5 | HIP 42269 | 25.04 |
| 2026-08-05 12:00 | 08:35:29.39 | -25:59:55.9 | HIP 42269 | 22.70 |
| 2026-08-06 00:00 | 08:35:39.46 | -26:00:34.0 | HIP 42269 | 20.35 |
| 2026-08-06 12:00 | 08:35:49.52 | -26:01:12.9 | HIP 42269 | 18.01 |
| 2026-08-07 00:00 | 08:35:59.56 | -26:01:52.6 | HIP 42269 | 15.68 |
| 2026-08-07 12:00 | 08:36:09.58 | -26:02:33.1 | HIP 42269 | 13.35 |
| 2026-08-08 00:00 | 08:36:19.59 | -26:03:14.3 | HIP 42269 | 11.04 |
| 2026-08-08 12:00 | 08:36:29.58 | -26:03:56.4 | HIP 42269 | 8.74 |
| 2026-08-09 00:00 | 08:36:39.55 | -26:04:39.2 | HIP 42269 | 6.50 |
| 2026-08-09 12:00 | 08:36:49.50 | -26:05:22.9 | HIP 42269 | 4.37 |
| 2026-08-10 00:00 | 08:36:59.43 | -26:06:07.3 | HIP 42269 | 2.67 |
| 2026-08-10 12:00 | 08:37:09.34 | -26:06:52.4 | HIP 42269 | 2.49 |
| 2026-08-11 00:00 | 08:37:19.24 | -26:07:38.4 | HIP 42269 | 4.05 |
| 2026-08-11 12:00 | 08:37:29.10 | -26:08:25.1 | HIP 42269 | 6.14 |
| 2026-08-12 00:00 | 08:37:38.95 | -26:09:12.5 | HIP 42334 | 6.77 |
| 2026-08-12 12:00 | 08:37:48.78 | -26:10:00.8 | HIP 42334 | 5.34 |
| 2026-08-13 00:00 | 08:37:58.58 | -26:10:49.7 | HIP 42334 | 4.69 |
| 2026-08-13 12:00 | 08:38:08.35 | -26:11:39.5 | HIP 42334 | 5.14 |
| 2026-08-14 00:00 | 08:38:18.11 | -26:12:30.0 | HIP 42334 | 6.46 |
| 2026-08-14 12:00 | 08:38:27.83 | -26:13:21.2 | HIP 42334 | 8.23 |
| 2026-08-15 00:00 | 08:38:37.54 | -26:14:13.2 | HIP 42334 | 10.23 |
| 2026-08-15 12:00 | 08:38:47.21 | -26:15:05.9 | HIP 42334 | 12.34 |
| 2026-08-16 00:00 | 08:38:56.86 | -26:15:59.3 | HIP 42334 | 14.52 |
| 2026-08-16 12:00 | 08:39:06.48 | -26:16:53.5 | HIP 42334 | 16.74 |
| 2026-08-17 00:00 | 08:39:16.07 | -26:17:48.4 | HIP 42334 | 18.98 |
| 2026-08-17 12:00 | 08:39:25.64 | -26:18:44.0 | HIP 42334 | 21.23 |
| 2026-08-18 00:00 | 08:39:35.17 | -26:19:40.4 | HIP 42334 | 23.50 |
| 2026-08-18 12:00 | 08:39:44.67 | -26:20:37.4 | HIP 42334 | 25.77 |
| 2026-08-19 00:00 | 08:39:54.15 | -26:21:35.2 | HIP 42334 | 28.05 |