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) |
|---|---|---|---|---|
| 2026-06-01 00:00 | 08:14:53.84 | -26:43:01.0 | HIP 40370 | 42.29 |
| 2026-06-01 12:00 | 08:15:00.92 | -26:41:41.6 | HIP 40611 | 40.68 |
| 2026-06-02 00:00 | 08:15:08.07 | -26:40:23.1 | HIP 40611 | 38.62 |
| 2026-06-02 12:00 | 08:15:15.27 | -26:39:05.6 | HIP 40611 | 36.56 |
| 2026-06-03 00:00 | 08:15:22.54 | -26:37:48.9 | HIP 40611 | 34.50 |
| 2026-06-03 12:00 | 08:15:29.88 | -26:36:33.1 | HIP 40611 | 32.43 |
| 2026-06-04 00:00 | 08:15:37.27 | -26:35:18.2 | HIP 40611 | 30.36 |
| 2026-06-04 12:00 | 08:15:44.72 | -26:34:04.3 | HIP 40611 | 28.29 |
| 2026-06-05 00:00 | 08:15:52.23 | -26:32:51.2 | HIP 40611 | 26.22 |
| 2026-06-05 12:00 | 08:15:59.80 | -26:31:39.1 | HIP 40611 | 24.14 |
| 2026-06-06 00:00 | 08:16:07.42 | -26:30:27.9 | HIP 40611 | 22.07 |
| 2026-06-06 12:00 | 08:16:15.11 | -26:29:17.6 | HIP 40611 | 19.98 |
| 2026-06-07 00:00 | 08:16:22.85 | -26:28:08.2 | HIP 40611 | 17.90 |
| 2026-06-07 12:00 | 08:16:30.65 | -26:26:59.7 | HIP 40611 | 15.82 |
| 2026-06-08 00:00 | 08:16:38.50 | -26:25:52.1 | HIP 40611 | 13.73 |
| 2026-06-08 12:00 | 08:16:46.41 | -26:24:45.5 | HIP 40611 | 11.64 |
| 2026-06-09 00:00 | 08:16:54.38 | -26:23:39.8 | HIP 40611 | 9.55 |
| 2026-06-09 12:00 | 08:17:02.39 | -26:22:35.0 | HIP 40611 | 7.47 |
| 2026-06-10 00:00 | 08:17:10.46 | -26:21:31.1 | HIP 40611 | 5.38 |
| 2026-06-10 12:00 | 08:17:18.59 | -26:20:28.2 | HIP 40611 | 3.33 |
| 2026-06-11 00:00 | 08:17:26.76 | -26:19:26.2 | HIP 40611 | 1.42 |
| 2026-06-11 12:00 | 08:17:34.99 | -26:18:25.1 | HIP 40611 | 1.35 |
| 2026-06-12 00:00 | 08:17:43.27 | -26:17:25.0 | HIP 40611 | 3.25 |
| 2026-06-12 12:00 | 08:17:51.60 | -26:16:25.8 | HIP 40611 | 5.32 |
| 2026-06-13 00:00 | 08:17:59.97 | -26:15:27.5 | HIP 40682 | 6.90 |
| 2026-06-13 12:00 | 08:18:08.40 | -26:14:30.2 | HIP 40682 | 6.71 |
| 2026-06-14 00:00 | 08:18:16.87 | -26:13:33.8 | HIP 40682 | 7.15 |
| 2026-06-14 12:00 | 08:18:25.40 | -26:12:38.3 | HIP 40682 | 8.12 |
| 2026-06-15 00:00 | 08:18:33.97 | -26:11:43.8 | HIP 40682 | 9.47 |
| 2026-06-15 12:00 | 08:18:42.58 | -26:10:50.2 | HIP 40682 | 11.05 |
| 2026-06-16 00:00 | 08:18:51.24 | -26:09:57.6 | HIP 40682 | 12.79 |
| 2026-06-16 12:00 | 08:18:59.95 | -26:09:05.9 | HIP 40682 | 14.62 |
| 2026-06-17 00:00 | 08:19:08.70 | -26:08:15.1 | HIP 40682 | 16.52 |
| 2026-06-17 12:00 | 08:19:17.49 | -26:07:25.3 | HIP 40682 | 18.47 |
| 2026-06-18 00:00 | 08:19:26.33 | -26:06:36.4 | HIP 40682 | 20.45 |
| 2026-06-18 12:00 | 08:19:35.20 | -26:05:48.5 | HIP 40868 | 19.73 |
| 2026-06-19 00:00 | 08:19:44.12 | -26:05:01.5 | HIP 40868 | 18.03 |
| 2026-06-19 12:00 | 08:19:53.08 | -26:04:15.5 | HIP 40868 | 16.45 |
| 2026-06-20 00:00 | 08:20:02.08 | -26:03:30.4 | HIP 40868 | 15.02 |
| 2026-06-20 12:00 | 08:20:11.12 | -26:02:46.2 | HIP 40868 | 13.81 |
| 2026-06-21 00:00 | 08:20:20.19 | -26:02:03.0 | HIP 40868 | 12.85 |
| 2026-06-21 12:00 | 08:20:29.31 | -26:01:20.8 | HIP 40868 | 12.23 |
| 2026-06-22 00:00 | 08:20:38.46 | -26:00:39.4 | HIP 40868 | 11.99 |