P/2023 S1 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | P/2023 S1 (PANSTARRS) |
| Type | P |
| Perihelion (tp_cal, UTC) | 2025-02-24T01:28:44.201280Z |
| Orbit solution date (soln_date, UTC) | 2026-05-22T14:12:28Z |
| Obs used | 1928 |
| NEO | - |
| M1 | 10.300 |
| K1 | 11.500 |
| PC | 0.030 |
| Discovery observation (MPC, UTC) | 2023-09-20T14:30:23.443200Z |
| Discovery magnitude (MPC) | 20.36 w |
| Discovery observatory (MPC) | F52 · Pan-STARRS 2, Haleakala |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2024-10-31.0000000 |
| e | 0.31884323 |
| q (au) | 2.619726 |
| a (au) | 3.845996 |
| i (deg) | 9.156216 |
| Ω (om, deg) | 317.292570 |
| ω (w, deg) | 180.274180 |
| M (ma, deg) | 344.833705 |
Magnitude
Scatter + Global Linear
$$ M_a = (9.337 + 5.218\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 9.337 |
| n | 5.218 |
| gf | 0.883 |
| gb | -0.801 |
| k | 0.997 |
| δ90 | 1.000 |
| 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 |
|---|---|---|---|
| 2023-09-15 | 2025-02-24 | +2.2459 | -1.234 |
| 2025-02-24 | 2026-02-25 | +16.8467 | -7.135 |
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 | 15:28:23.59 | -26:49:24.0 | HIP 75854 | 18.51 |
| 2026-09-20 12:00 | 15:28:54.80 | -26:50:17.1 | HIP 75854 | 13.20 |
| 2026-09-21 00:00 | 15:29:26.11 | -26:51:10.4 | HIP 75854 | 10.22 |
| 2026-09-21 12:00 | 15:29:57.53 | -26:52:04.1 | HIP 75854 | 11.58 |
| 2026-09-22 00:00 | 15:30:29.06 | -26:52:58.2 | HIP 75854 | 16.26 |
| 2026-09-22 12:00 | 15:31:00.69 | -26:53:52.5 | HIP 75854 | 22.28 |
| 2026-09-23 00:00 | 15:31:32.42 | -26:54:47.1 | HIP 76099 | 20.26 |
| 2026-09-23 12:00 | 15:32:04.25 | -26:55:42.0 | HIP 76099 | 17.39 |
| 2026-09-24 00:00 | 15:32:36.19 | -26:56:37.2 | HIP 76099 | 17.23 |
| 2026-09-24 12:00 | 15:33:08.22 | -26:57:32.7 | HIP 76099 | 19.88 |
| 2026-09-25 00:00 | 15:33:40.35 | -26:58:28.5 | HIP 76284 | 19.47 |
| 2026-09-25 12:00 | 15:34:12.59 | -26:59:24.5 | HIP 76284 | 13.34 |
| 2026-09-26 00:00 | 15:34:44.92 | -27:00:20.8 | HIP 76284 | 9.03 |
| 2026-09-26 12:00 | 15:35:17.35 | -27:01:17.3 | HIP 76284 | 9.52 |
| 2026-09-27 00:00 | 15:35:49.87 | -27:02:14.1 | HIP 76284 | 14.36 |
| 2026-09-27 12:00 | 15:36:22.49 | -27:03:11.1 | HIP 76284 | 20.71 |
| 2026-09-28 00:00 | 15:36:55.20 | -27:04:08.4 | HIP 76284 | 27.57 |
| 2026-09-28 12:00 | 15:37:28.01 | -27:05:05.9 | HIP 76611 | 22.26 |
| 2026-09-29 00:00 | 15:38:00.91 | -27:06:03.5 | HIP 76611 | 18.23 |
| 2026-09-29 12:00 | 15:38:33.91 | -27:07:01.4 | HIP 76673 | 11.72 |
| 2026-09-30 00:00 | 15:39:06.99 | -27:07:59.5 | HIP 76673 | 4.54 |
| 2026-09-30 12:00 | 15:39:40.17 | -27:08:57.8 | HIP 76673 | 3.77 |
| 2026-10-01 00:00 | 15:40:13.44 | -27:09:56.3 | HIP 76673 | 10.91 |
| 2026-10-01 12:00 | 15:40:46.80 | -27:10:55.0 | HIP 76673 | 18.33 |
| 2026-10-02 00:00 | 15:41:20.25 | -27:11:53.8 | HIP 76702 | 24.17 |
| 2026-10-02 12:00 | 15:41:53.79 | -27:12:52.9 | HIP 76702 | 30.71 |
| 2026-10-03 00:00 | 15:42:27.42 | -27:13:52.1 | HIP 77087 | 29.00 |
| 2026-10-03 12:00 | 15:43:01.14 | -27:14:51.4 | HIP 77087 | 22.07 |
| 2026-10-04 00:00 | 15:43:34.94 | -27:15:50.9 | HIP 77087 | 15.71 |
| 2026-10-04 12:00 | 15:44:08.83 | -27:16:50.5 | HIP 77087 | 11.01 |
| 2026-10-05 00:00 | 15:44:42.81 | -27:17:50.3 | HIP 77087 | 10.52 |
| 2026-10-05 12:00 | 15:45:16.87 | -27:18:50.2 | HIP 77087 | 14.71 |
| 2026-10-06 00:00 | 15:45:51.02 | -27:19:50.3 | HIP 77087 | 20.96 |
| 2026-10-06 12:00 | 15:46:25.25 | -27:20:50.4 | HIP 77339 | 19.85 |
| 2026-10-07 00:00 | 15:46:59.56 | -27:21:50.7 | HIP 77339 | 17.25 |
| 2026-10-07 12:00 | 15:47:33.96 | -27:22:51.1 | HIP 77339 | 17.88 |
| 2026-10-08 00:00 | 15:48:08.43 | -27:23:51.6 | HIP 77449 | 13.46 |
| 2026-10-08 12:00 | 15:48:42.99 | -27:24:52.1 | HIP 77449 | 10.07 |
| 2026-10-09 00:00 | 15:49:17.63 | -27:25:52.8 | HIP 77449 | 11.89 |
| 2026-10-09 12:00 | 15:49:52.35 | -27:26:53.6 | HIP 77449 | 17.37 |
| 2026-10-10 00:00 | 15:50:27.15 | -27:27:54.4 | HIP 77449 | 24.16 |
| 2026-10-10 12:00 | 15:51:02.02 | -27:28:55.3 | HIP 77531 | 28.64 |
| 2026-10-11 00:00 | 15:51:36.97 | -27:29:56.2 | HIP 77821 | 27.19 |