C/2023 R1 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 R1 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2026-04-13T11:20:27.602880Z |
| Orbit solution date (soln_date, UTC) | 2026-07-21T13:12:11Z |
| Obs used | 4209 |
| NEO | - |
| M1 | 7.400 |
| K1 | 8.750 |
| 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) | 2025-07-11.0000000 |
| e | 1.00223081 |
| q (au) | 3.569814 |
| a (au) | -1600.235615 |
| i (deg) | 149.316857 |
| Ω (om, deg) | 62.562991 |
| ω (w, deg) | 144.273151 |
| M (ma, deg) | -0.004257 |
Magnitude
Scatter + Global Linear
$$ M_a = (5.818 + 4.073\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 5.818 |
| n | 4.073 |
| gf | 0.999 |
| gb | -0.927 |
| k | 1.000 |
| δ90 | 9.999 |
| 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 | +5.7575 | -4.989 |
| 2024-08-15 | 2025-05-30 | +0.0082 | -0.142 |
| 2025-05-30 | 2025-09-19 | -16.4218 | +10.733 |
| 2025-09-19 | 2026-04-12 | +21.2280 | -11.975 |
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) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 15:59:47.56 | -11:57:46.2 | HIP 78484 | 24.84 |
| 2026-07-29 12:00 | 15:59:07.60 | -12:00:40.8 | HIP 78484 | 33.06 |
| 2026-07-30 00:00 | 15:58:28.16 | -12:03:35.1 | HIP 78453 | 40.33 |
| 2026-07-30 12:00 | 15:57:49.23 | -12:06:29.0 | HIP 78453 | 48.25 |
| 2026-07-31 00:00 | 15:57:10.80 | -12:09:22.6 | HIP 78084 | 46.66 |
| 2026-07-31 12:00 | 15:56:32.88 | -12:12:15.8 | HIP 77863 | 38.44 |
| 2026-08-01 00:00 | 15:55:55.46 | -12:15:08.7 | HIP 77863 | 30.11 |
| 2026-08-01 12:00 | 15:55:18.54 | -12:18:01.3 | HIP 77863 | 22.90 |
| 2026-08-02 00:00 | 15:54:42.12 | -12:20:53.5 | HIP 77863 | 18.00 |
| 2026-08-02 12:00 | 15:54:06.20 | -12:23:45.5 | HIP 77863 | 17.28 |
| 2026-08-03 00:00 | 15:53:30.77 | -12:26:37.0 | HIP 77863 | 21.03 |
| 2026-08-03 12:00 | 15:52:55.83 | -12:29:28.3 | HIP 77708 | 14.63 |
| 2026-08-04 00:00 | 15:52:21.38 | -12:32:19.3 | HIP 77708 | 5.95 |
| 2026-08-04 12:00 | 15:51:47.41 | -12:35:09.9 | HIP 77708 | 3.73 |
| 2026-08-05 00:00 | 15:51:13.92 | -12:38:00.3 | HIP 77666 | 1.71 |
| 2026-08-05 12:00 | 15:50:40.92 | -12:40:50.3 | HIP 77666 | 10.24 |
| 2026-08-06 00:00 | 15:50:08.39 | -12:43:40.1 | HIP 77666 | 18.66 |
| 2026-08-06 12:00 | 15:49:36.34 | -12:46:29.5 | HIP 77392 | 25.13 |
| 2026-08-07 00:00 | 15:49:04.76 | -12:49:18.7 | HIP 77392 | 18.58 |
| 2026-08-07 12:00 | 15:48:33.65 | -12:52:07.6 | HIP 77392 | 13.98 |
| 2026-08-08 00:00 | 15:48:03.01 | -12:54:56.3 | HIP 77392 | 13.31 |
| 2026-08-08 12:00 | 15:47:32.83 | -12:57:44.6 | HIP 77392 | 16.88 |
| 2026-08-09 00:00 | 15:47:03.11 | -13:00:32.7 | HIP 77392 | 22.66 |
| 2026-08-09 12:00 | 15:46:33.85 | -13:03:20.6 | HIP 77392 | 29.29 |
| 2026-08-10 00:00 | 15:46:05.05 | -13:06:08.2 | HIP 77392 | 36.24 |
| 2026-08-10 12:00 | 15:45:36.70 | -13:08:55.5 | HIP 76982 | 36.46 |
| 2026-08-11 00:00 | 15:45:08.80 | -13:11:42.6 | HIP 76982 | 30.41 |
| 2026-08-11 12:00 | 15:44:41.34 | -13:14:29.4 | HIP 76982 | 25.15 |
| 2026-08-12 00:00 | 15:44:14.33 | -13:17:16.0 | HIP 76982 | 21.18 |
| 2026-08-12 12:00 | 15:43:47.75 | -13:20:02.4 | HIP 76983 | 16.16 |
| 2026-08-13 00:00 | 15:43:21.61 | -13:22:48.5 | HIP 76983 | 10.86 |
| 2026-08-13 12:00 | 15:42:55.91 | -13:25:34.4 | HIP 76983 | 8.39 |
| 2026-08-14 00:00 | 15:42:30.64 | -13:28:20.1 | HIP 76983 | 10.68 |
| 2026-08-14 12:00 | 15:42:05.79 | -13:31:05.6 | HIP 76983 | 15.66 |
| 2026-08-15 00:00 | 15:41:41.37 | -13:33:50.8 | HIP 76983 | 21.45 |
| 2026-08-15 12:00 | 15:41:17.37 | -13:36:35.8 | HIP 76789 | 16.74 |
| 2026-08-16 00:00 | 15:40:53.78 | -13:39:20.7 | HIP 76789 | 12.12 |
| 2026-08-16 12:00 | 15:40:30.61 | -13:42:05.2 | HIP 76789 | 9.67 |
| 2026-08-17 00:00 | 15:40:07.84 | -13:44:49.6 | HIP 76789 | 10.81 |
| 2026-08-17 12:00 | 15:39:45.49 | -13:47:33.8 | HIP 76676 | 8.46 |
| 2026-08-18 00:00 | 15:39:23.53 | -13:50:17.8 | HIP 76676 | 4.41 |
| 2026-08-18 12:00 | 15:39:01.97 | -13:53:01.6 | HIP 76676 | 6.15 |
| 2026-08-19 00:00 | 15:38:40.81 | -13:55:45.1 | HIP 76676 | 11.13 |