C/2023 R1 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 R1 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2026-04-13T11:55:03.336960Z |
| Orbit solution date (soln_date, UTC) | 2026-05-28T12:12:15Z |
| Obs used | 3452 |
| NEO | - |
| M1 | 8.100 |
| K1 | 7.750 |
| 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) | 2025-04-27.0000000 |
| e | 1.00215456 |
| q (au) | 3.569710 |
| a (au) | -1656.818581 |
| i (deg) | 149.316827 |
| Ω (om, deg) | 62.560887 |
| ω (w, deg) | 144.275724 |
| M (ma, deg) | -0.005137 |
Magnitude
Scatter + Global Linear
$$ M_a = (7.500 + 2.960\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 7.500 |
| n | 2.960 |
| gf | 0.965 |
| gb | -0.901 |
| k | 1.000 |
| δ90 | 9.367 |
| 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 | +6.0783 | -5.141 |
| 2024-08-15 | 2025-01-20 | +0.0798 | -0.209 |
| 2025-01-20 | 2025-09-19 | -6.4445 | +4.341 |
| 2025-09-19 | 2026-04-12 | +20.3413 | -11.693 |
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) |
|---|---|---|---|---|
| 2026-06-01 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 |
| 2026-06-02 12:00 | 18:00:13.34 | -06:09:15.7 | HIP 88229 | 12.58 |
| 2026-06-03 00:00 | 17:59:01.64 | -06:11:58.5 | HIP 88050 | 26.69 |
| 2026-06-03 12:00 | 17:57:49.67 | -06:14:42.6 | HIP 87830 | 27.33 |
| 2026-06-04 00:00 | 17:56:37.45 | -06:17:27.9 | HIP 87830 | 15.80 |
| 2026-06-04 12:00 | 17:55:24.97 | -06:20:14.4 | HIP 87830 | 20.32 |
| 2026-06-05 00:00 | 17:54:12.26 | -06:23:02.1 | HIP 87495 | 27.36 |
| 2026-06-05 12:00 | 17:52:59.33 | -06:25:51.0 | HIP 87495 | 17.98 |
| 2026-06-06 00:00 | 17:51:46.18 | -06:28:41.0 | HIP 87396 | 23.23 |
| 2026-06-06 12:00 | 17:50:32.83 | -06:31:32.2 | HIP 87396 | 25.70 |
| 2026-06-07 00:00 | 17:49:19.29 | -06:34:24.4 | HIP 87322 | 36.49 |
| 2026-06-07 12:00 | 17:48:05.57 | -06:37:17.7 | HIP 87016 | 23.57 |
| 2026-06-08 00:00 | 17:46:51.69 | -06:40:12.0 | HIP 87016 | 11.55 |
| 2026-06-08 12:00 | 17:45:37.65 | -06:43:07.4 | HIP 87016 | 20.06 |
| 2026-06-09 00:00 | 17:44:23.46 | -06:46:03.8 | HIP 86768 | 20.78 |
| 2026-06-09 12:00 | 17:43:09.15 | -06:49:01.1 | HIP 86768 | 18.35 |
| 2026-06-10 00:00 | 17:41:54.72 | -06:51:59.3 | HIP 86768 | 30.66 |
| 2026-06-10 12:00 | 17:40:40.18 | -06:54:58.5 | HIP 86447 | 29.24 |
| 2026-06-11 00:00 | 17:39:25.56 | -06:57:58.6 | HIP 86447 | 29.78 |
| 2026-06-11 12:00 | 17:38:10.85 | -07:00:59.6 | HIP 86447 | 40.31 |
| 2026-06-12 00:00 | 17:36:56.07 | -07:04:01.3 | HIP 86108 | 54.38 |
| 2026-06-12 12:00 | 17:35:41.24 | -07:07:03.9 | HIP 85929 | 38.11 |
| 2026-06-13 00:00 | 17:34:26.37 | -07:10:07.3 | HIP 85929 | 22.85 |
| 2026-06-13 12:00 | 17:33:11.48 | -07:13:11.4 | HIP 85929 | 17.31 |
| 2026-06-14 00:00 | 17:31:56.56 | -07:16:16.3 | HIP 85929 | 28.02 |
| 2026-06-14 12:00 | 17:30:41.65 | -07:19:21.9 | HIP 85631 | 26.94 |
| 2026-06-15 00:00 | 17:29:26.75 | -07:22:28.1 | HIP 85631 | 28.82 |
| 2026-06-15 12:00 | 17:28:11.87 | -07:25:35.0 | HIP 85408 | 16.24 |
| 2026-06-16 00:00 | 17:26:57.03 | -07:28:42.5 | HIP 85408 | 10.40 |
| 2026-06-16 12:00 | 17:25:42.24 | -07:31:50.6 | HIP 85408 | 25.70 |
| 2026-06-17 00:00 | 17:24:27.52 | -07:34:59.3 | HIP 85064 | 35.35 |
| 2026-06-17 12:00 | 17:23:12.87 | -07:38:08.4 | HIP 85064 | 31.94 |
| 2026-06-18 00:00 | 17:21:58.32 | -07:41:18.1 | HIP 84803 | 35.48 |
| 2026-06-18 12:00 | 17:20:43.86 | -07:44:28.3 | HIP 84803 | 20.06 |
| 2026-06-19 00:00 | 17:19:29.53 | -07:47:38.9 | HIP 84803 | 15.67 |
| 2026-06-19 12:00 | 17:18:15.32 | -07:50:49.9 | HIP 84582 | 12.95 |
| 2026-06-20 00:00 | 17:17:01.25 | -07:54:01.3 | HIP 84581 | 5.68 |
| 2026-06-20 12:00 | 17:15:47.33 | -07:57:13.1 | HIP 84581 | 24.24 |
| 2026-06-21 00:00 | 17:14:33.58 | -08:00:25.2 | HIP 84303 | 24.64 |
| 2026-06-21 12:00 | 17:13:20.01 | -08:03:37.6 | HIP 84277 | 22.16 |
| 2026-06-22 00:00 | 17:12:06.63 | -08:06:50.3 | HIP 84277 | 29.64 |