C/2023 R1 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 R1 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2026-04-13T12:30:03.288960Z |
| Orbit solution date (soln_date, UTC) | 2026-03-31T09:42:18Z |
| Obs used | 2950 |
| NEO | - |
| M1 | 9.800 |
| K1 | 5.500 |
| PC | 0.030 |
| Discovery observation (MPC, UTC) | 2023-09-07T13:40:49.296000Z |
| Discovery magnitude (MPC) | 20.17 w |
| Discovery observatory (MPC) | F52 · Pan-STARRS 2, Haleakala |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2025-02-26.0000000 |
| e | 1.00208742 |
| q (au) | 3.569582 |
| a (au) | -1710.044088 |
| i (deg) | 149.316598 |
| Ω (om, deg) | 62.558021 |
| ω (w, deg) | 144.277829 |
| M (ma, deg) | -0.005736 |
Magnitude
Scatter + Global Linear
$$ M_a = (10.847 + 2.284\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 10.847 |
| n | 2.284 |
| gf | 0.950 |
| gb | -0.561 |
| k | 0.800 |
| δ90 | 8.411 |
| 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 |
|---|---|---|---|
| 2023-07-29 | 2025-05-29 | +3.3230 | -2.614 |
| 2025-05-29 | 2025-09-19 | -12.1824 | +7.719 |
| 2025-09-19 | 2026-03-24 | +23.6304 | -13.862 |
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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 19:31:41.90 | -03:32:16.8 | HIP 96027 | 22.07 |
| 2026-03-26 12:00 | 19:31:31.25 | -03:32:24.3 | HIP 96027 | 21.66 |
| 2026-03-27 00:00 | 19:31:20.29 | -03:32:32.0 | HIP 96027 | 21.58 |
| 2026-03-27 12:00 | 19:31:09.01 | -03:32:40.1 | HIP 96027 | 21.86 |
| 2026-03-28 00:00 | 19:30:57.42 | -03:32:48.4 | HIP 96027 | 22.51 |
| 2026-03-28 12:00 | 19:30:45.52 | -03:32:57.1 | HIP 95909 | 23.11 |
| 2026-03-29 00:00 | 19:30:33.29 | -03:33:06.1 | HIP 95909 | 22.52 |
| 2026-03-29 12:00 | 19:30:20.74 | -03:33:15.4 | HIP 95909 | 22.34 |
| 2026-03-30 00:00 | 19:30:07.86 | -03:33:25.0 | HIP 95909 | 22.62 |
| 2026-03-30 12:00 | 19:29:54.65 | -03:33:35.0 | HIP 95909 | 23.36 |
| 2026-03-31 00:00 | 19:29:41.11 | -03:33:45.4 | HIP 95909 | 24.57 |
| 2026-03-31 12:00 | 19:29:27.23 | -03:33:56.2 | HIP 95909 | 26.20 |
| 2026-04-01 00:00 | 19:29:13.01 | -03:34:07.3 | HIP 95909 | 28.23 |
| 2026-04-01 12:00 | 19:28:58.45 | -03:34:18.9 | HIP 95909 | 30.59 |
| 2026-04-02 00:00 | 19:28:43.55 | -03:34:30.8 | HIP 95909 | 33.25 |
| 2026-04-02 12:00 | 19:28:28.29 | -03:34:43.3 | HIP 95909 | 36.18 |
| 2026-04-03 00:00 | 19:28:12.69 | -03:34:56.1 | HIP 95909 | 39.32 |
| 2026-04-03 12:00 | 19:27:56.72 | -03:35:09.4 | HIP 95494 | 38.51 |
| 2026-04-04 00:00 | 19:27:40.40 | -03:35:23.2 | HIP 95494 | 34.50 |
| 2026-04-04 12:00 | 19:27:23.72 | -03:35:37.5 | HIP 95494 | 30.42 |
| 2026-04-05 00:00 | 19:27:06.67 | -03:35:52.3 | HIP 95494 | 26.29 |
| 2026-04-05 12:00 | 19:26:49.25 | -03:36:07.6 | HIP 95494 | 22.11 |
| 2026-04-06 00:00 | 19:26:31.46 | -03:36:23.5 | HIP 95494 | 17.92 |
| 2026-04-06 12:00 | 19:26:13.29 | -03:36:39.9 | HIP 95494 | 13.82 |
| 2026-04-07 00:00 | 19:25:54.74 | -03:36:56.8 | HIP 95494 | 10.02 |
| 2026-04-07 12:00 | 19:25:35.81 | -03:37:14.3 | HIP 95494 | 7.24 |
| 2026-04-08 00:00 | 19:25:16.49 | -03:37:32.5 | HIP 95494 | 7.03 |
| 2026-04-08 12:00 | 19:24:56.79 | -03:37:51.2 | HIP 95494 | 9.71 |
| 2026-04-09 00:00 | 19:24:36.69 | -03:38:10.5 | HIP 95494 | 13.79 |
| 2026-04-09 12:00 | 19:24:16.19 | -03:38:30.5 | HIP 95494 | 18.43 |
| 2026-04-10 00:00 | 19:23:55.29 | -03:38:51.2 | HIP 95236 | 20.73 |
| 2026-04-10 12:00 | 19:23:33.99 | -03:39:12.5 | HIP 95236 | 15.47 |
| 2026-04-11 00:00 | 19:23:12.28 | -03:39:34.5 | HIP 95236 | 10.18 |
| 2026-04-11 12:00 | 19:22:50.16 | -03:39:57.2 | HIP 95236 | 5.11 |
| 2026-04-12 00:00 | 19:22:27.62 | -03:40:20.6 | HIP 95225 | 2.37 |
| 2026-04-12 12:00 | 19:22:04.67 | -03:40:44.7 | HIP 95225 | 5.88 |
| 2026-04-13 00:00 | 19:21:41.29 | -03:41:09.6 | HIP 95225 | 11.48 |
| 2026-04-13 12:00 | 19:21:17.49 | -03:41:35.3 | HIP 95225 | 17.35 |
| 2026-04-14 00:00 | 19:20:53.26 | -03:42:01.7 | HIP 95225 | 23.38 |
| 2026-04-14 12:00 | 19:20:28.60 | -03:42:29.0 | HIP 94917 | 24.08 |
| 2026-04-15 00:00 | 19:20:03.50 | -03:42:57.0 | HIP 94917 | 17.84 |
| 2026-04-15 12:00 | 19:19:37.96 | -03:43:25.9 | HIP 94917 | 11.53 |
| 2026-04-16 00:00 | 19:19:11.98 | -03:43:55.7 | HIP 94917 | 5.30 |