C/2023 R1 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 R1 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2026-04-13T12:07:20.510400Z |
| Orbit solution date (soln_date, UTC) | 2026-05-08T13:42:12Z |
| Obs used | 3216 |
| NEO | - |
| M1 | 8.900 |
| K1 | 6.750 |
| 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) | 2025-03-31.0000000 |
| e | 1.00213358 |
| q (au) | 3.569668 |
| a (au) | -1673.090983 |
| i (deg) | 149.316748 |
| Ω (om, deg) | 62.559673 |
| ω (w, deg) | 144.276281 |
| M (ma, deg) | -0.005451 |
Magnitude
Scatter + Global Linear
$$ M_a = (8.300 + 2.453\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.300 |
| n | 2.453 |
| gf | 0.974 |
| gb | -0.503 |
| k | 1.000 |
| δ90 | 9.952 |
| 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 | 2024-08-15 | +6.8453 | -5.740 |
| 2024-08-15 | 2025-09-09 | -2.3051 | +1.636 |
| 2025-09-09 | 2026-04-12 | +18.8174 | -10.977 |
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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 18:45:23.54 | -04:35:56.0 | HIP 92028 | 1.27 |
| 2026-05-12 12:00 | 18:44:30.63 | -04:37:32.8 | HIP 92028 | 14.53 |
| 2026-05-13 00:00 | 18:43:37.19 | -04:39:11.2 | HIP 92028 | 27.95 |
| 2026-05-13 12:00 | 18:42:43.22 | -04:40:51.2 | HIP 91706 | 24.85 |
| 2026-05-14 00:00 | 18:41:48.72 | -04:42:32.7 | HIP 91598 | 19.90 |
| 2026-05-14 12:00 | 18:40:53.68 | -04:44:15.9 | HIP 91598 | 14.57 |
| 2026-05-15 00:00 | 18:39:58.12 | -04:46:00.7 | HIP 91598 | 20.35 |
| 2026-05-15 12:00 | 18:39:02.04 | -04:47:47.2 | HIP 91368 | 16.42 |
| 2026-05-16 00:00 | 18:38:05.43 | -04:49:35.2 | HIP 91337 | 5.11 |
| 2026-05-16 12:00 | 18:37:08.31 | -04:51:24.9 | HIP 91337 | 9.73 |
| 2026-05-17 00:00 | 18:36:10.67 | -04:53:16.2 | HIP 91215 | 19.24 |
| 2026-05-17 12:00 | 18:35:12.51 | -04:55:09.1 | HIP 91038 | 15.47 |
| 2026-05-18 00:00 | 18:34:13.85 | -04:57:03.7 | HIP 91038 | 8.26 |
| 2026-05-18 12:00 | 18:33:14.69 | -04:59:00.0 | HIP 90946 | 10.92 |
| 2026-05-19 00:00 | 18:32:15.02 | -05:00:57.8 | HIP 90946 | 15.67 |
| 2026-05-19 12:00 | 18:31:14.86 | -05:02:57.3 | HIP 90737 | 26.60 |
| 2026-05-20 00:00 | 18:30:14.20 | -05:04:58.4 | HIP 90737 | 29.18 |
| 2026-05-20 12:00 | 18:29:13.06 | -05:07:01.1 | HIP 90737 | 38.31 |
| 2026-05-21 00:00 | 18:28:11.44 | -05:09:05.5 | HIP 90390 | 35.79 |
| 2026-05-21 12:00 | 18:27:09.34 | -05:11:11.5 | HIP 90390 | 26.18 |
| 2026-05-22 00:00 | 18:26:06.78 | -05:13:19.1 | HIP 90390 | 24.01 |
| 2026-05-22 12:00 | 18:25:03.74 | -05:15:28.3 | HIP 90220 | 17.78 |
| 2026-05-23 00:00 | 18:24:00.25 | -05:17:39.1 | HIP 90147 | 9.21 |
| 2026-05-23 12:00 | 18:22:56.30 | -05:19:51.5 | HIP 90147 | 16.88 |
| 2026-05-24 00:00 | 18:21:51.91 | -05:22:05.5 | HIP 89897 | 19.97 |
| 2026-05-24 12:00 | 18:20:47.07 | -05:24:21.1 | HIP 89897 | 6.00 |
| 2026-05-25 00:00 | 18:19:41.80 | -05:26:38.2 | HIP 89780 | 6.40 |
| 2026-05-25 12:00 | 18:18:36.11 | -05:28:56.9 | HIP 89780 | 10.50 |
| 2026-05-26 00:00 | 18:17:29.99 | -05:31:17.1 | HIP 89627 | 0.83 |
| 2026-05-26 12:00 | 18:16:23.47 | -05:33:38.8 | HIP 89477 | 13.26 |
| 2026-05-27 00:00 | 18:15:16.53 | -05:36:02.1 | HIP 89477 | 8.73 |
| 2026-05-27 12:00 | 18:14:09.21 | -05:38:26.9 | HIP 89391 | 6.46 |
| 2026-05-28 00:00 | 18:13:01.49 | -05:40:53.1 | HIP 89174 | 16.77 |
| 2026-05-28 12:00 | 18:11:53.39 | -05:43:20.9 | HIP 89174 | 5.93 |
| 2026-05-29 00:00 | 18:10:44.91 | -05:45:50.1 | HIP 88969 | 18.23 |
| 2026-05-29 12:00 | 18:09:36.07 | -05:48:20.7 | HIP 88969 | 9.14 |
| 2026-05-30 00:00 | 18:08:26.88 | -05:50:52.8 | HIP 88892 | 14.12 |
| 2026-05-30 12:00 | 18:07:17.34 | -05:53:26.3 | HIP 88892 | 27.40 |
| 2026-05-31 00:00 | 18:06:07.46 | -05:56:01.1 | HIP 88623 | 20.37 |
| 2026-05-31 12:00 | 18:04:57.26 | -05:58:37.4 | HIP 88561 | 22.42 |
| 2026-06-01 00:00 | 18:03:46.73 | -06:01:15.0 | HIP 88561 | 26.68 |
| 2026-06-01 12:00 | 18:02:35.90 | -06:03:53.9 | HIP 88329 | 20.05 |
| 2026-06-02 00:00 | 18:01:24.77 | -06:06:34.2 | HIP 88229 | 5.58 |