C/2025 R3 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2025 R3 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2026-04-19T21:31:19.390080Z |
| Orbit solution date (soln_date, UTC) | 2026-01-13T08:12:19Z |
| Obs used | 412 |
| NEO | - |
| M1 | 14.000 |
| K1 | 6.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2025-09-08T11:13:22.022400Z |
| Discovery magnitude (MPC) | 19.85 i |
| Discovery observatory (MPC) | F52 · Pan-STARRS 2, Haleakala |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2025-11-05.0000000 |
| e | 1.00032848 |
| q (au) | 0.498602 |
| a (au) | -1517.905498 |
| i (deg) | 124.729345 |
| Ω (om, deg) | 38.692101 |
| ω (w, deg) | 162.226608 |
| M (ma, deg) | -0.002765 |
Magnitude
Scatter + Global Linear
$$ M_a = (11.997 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 11.997 |
| n | 6.000 |
| gf | 1.000 |
| gb | -0.704 |
| k | 0.800 |
| δ90 | 10.000 |
| 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 |
|---|---|---|---|
| 2025-09-07 | 2025-10-30 | -10.0937 | +5.124 |
| 2025-10-30 | 2025-12-30 | -1.1122 | +0.713 |
| 2025-12-30 | 2026-01-17 | +37.2970 | -11.749 |
| 2026-01-17 | 2026-02-08 | +4.9865 | -2.402 |
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) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 22:14:52.50 | +17:41:20.7 | HIP 109793 | 21.33 |
| 2026-02-03 12:00 | 22:14:59.83 | +17:40:28.9 | HIP 109793 | 22.80 |
| 2026-02-04 00:00 | 22:15:07.29 | +17:39:39.7 | HIP 109793 | 24.32 |
| 2026-02-04 12:00 | 22:15:14.86 | +17:38:53.4 | HIP 109793 | 25.87 |
| 2026-02-05 00:00 | 22:15:22.56 | +17:38:09.8 | HIP 109793 | 27.44 |
| 2026-02-05 12:00 | 22:15:30.37 | +17:37:28.9 | HIP 109793 | 29.05 |
| 2026-02-06 00:00 | 22:15:38.30 | +17:36:50.7 | HIP 109793 | 30.68 |
| 2026-02-06 12:00 | 22:15:46.34 | +17:36:15.3 | HIP 110069 | 29.58 |
| 2026-02-07 00:00 | 22:15:54.49 | +17:35:42.5 | HIP 110069 | 27.58 |
| 2026-02-07 12:00 | 22:16:02.75 | +17:35:12.4 | HIP 110069 | 25.57 |
| 2026-02-08 00:00 | 22:16:11.12 | +17:34:45.0 | HIP 110069 | 23.56 |
| 2026-02-08 12:00 | 22:16:19.60 | +17:34:20.2 | HIP 110069 | 21.56 |
| 2026-02-09 00:00 | 22:16:28.18 | +17:33:58.1 | HIP 110069 | 19.57 |
| 2026-02-09 12:00 | 22:16:36.86 | +17:33:38.5 | HIP 110069 | 17.60 |
| 2026-02-10 00:00 | 22:16:45.64 | +17:33:21.6 | HIP 110069 | 15.66 |
| 2026-02-10 12:00 | 22:16:54.53 | +17:33:07.3 | HIP 110069 | 13.78 |
| 2026-02-11 00:00 | 22:17:03.51 | +17:32:55.6 | HIP 110069 | 12.00 |
| 2026-02-11 12:00 | 22:17:12.58 | +17:32:46.4 | HIP 110069 | 10.37 |
| 2026-02-12 00:00 | 22:17:21.76 | +17:32:39.8 | HIP 110069 | 9.00 |
| 2026-02-12 12:00 | 22:17:31.02 | +17:32:35.7 | HIP 110069 | 8.04 |
| 2026-02-13 00:00 | 22:17:40.37 | +17:32:34.2 | HIP 110069 | 7.67 |
| 2026-02-13 12:00 | 22:17:49.81 | +17:32:35.2 | HIP 110069 | 7.97 |
| 2026-02-14 00:00 | 22:17:59.35 | +17:32:38.6 | HIP 110069 | 8.90 |
| 2026-02-14 12:00 | 22:18:08.96 | +17:32:44.6 | HIP 110069 | 10.30 |
| 2026-02-15 00:00 | 22:18:18.66 | +17:32:53.0 | HIP 110069 | 12.03 |
| 2026-02-15 12:00 | 22:18:28.45 | +17:33:03.9 | HIP 110069 | 13.97 |
| 2026-02-16 00:00 | 22:18:38.31 | +17:33:17.3 | HIP 110069 | 16.05 |
| 2026-02-16 12:00 | 22:18:48.26 | +17:33:33.0 | HIP 110069 | 18.24 |
| 2026-02-17 00:00 | 22:18:58.28 | +17:33:51.2 | HIP 110069 | 20.50 |
| 2026-02-17 12:00 | 22:19:08.39 | +17:34:11.7 | HIP 110069 | 22.83 |
| 2026-02-18 00:00 | 22:19:18.56 | +17:34:34.7 | HIP 110069 | 25.21 |
| 2026-02-18 12:00 | 22:19:28.82 | +17:35:00.0 | HIP 110069 | 27.64 |
| 2026-02-19 00:00 | 22:19:39.14 | +17:35:27.6 | HIP 110189 | 30.05 |
| 2026-02-19 12:00 | 22:19:49.54 | +17:35:57.6 | HIP 110363 | 29.51 |
| 2026-02-20 00:00 | 22:20:00.01 | +17:36:29.9 | HIP 110363 | 27.51 |
| 2026-02-20 12:00 | 22:20:10.55 | +17:37:04.4 | HIP 110363 | 25.56 |
| 2026-02-21 00:00 | 22:20:21.16 | +17:37:41.2 | HIP 110363 | 23.70 |
| 2026-02-21 12:00 | 22:20:31.83 | +17:38:20.3 | HIP 110363 | 21.94 |
| 2026-02-22 00:00 | 22:20:42.58 | +17:39:01.6 | HIP 110363 | 20.32 |
| 2026-02-22 12:00 | 22:20:53.39 | +17:39:45.2 | HIP 110363 | 18.90 |
| 2026-02-23 00:00 | 22:21:04.26 | +17:40:30.9 | HIP 110363 | 17.74 |
| 2026-02-23 12:00 | 22:21:15.21 | +17:41:18.8 | HIP 110363 | 16.89 |
| 2026-02-24 00:00 | 22:21:26.21 | +17:42:08.8 | HIP 110363 | 16.43 |