C/2025 R3 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2025 R3 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2026-04-19T21:29:38.457600Z |
| Orbit solution date (soln_date, UTC) | 2026-03-31T09:42:19Z |
| Obs used | 581 |
| NEO | - |
| M1 | 12.000 |
| K1 | 10.750 |
| PC | 0.030 |
| 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) | 2025-12-06.0000000 |
| e | 1.00034425 |
| q (au) | 0.498616 |
| a (au) | -1448.392670 |
| i (deg) | 124.730494 |
| Ω (om, deg) | 38.693020 |
| ω (w, deg) | 162.225543 |
| M (ma, deg) | -0.002412 |
Magnitude
Scatter + Global Linear
$$ M_a = (9.430 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 9.430 |
| n | 6.000 |
| gf | 1.000 |
| gb | -0.964 |
| k | 0.999 |
| 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 | 2026-01-11 | -2.1598 | +0.993 |
| 2026-01-11 | 2026-04-01 | +2.2806 | -0.982 |
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 | 22:36:39.92 | +19:21:08.8 | HIP 111669 | 15.34 |
| 2026-03-26 12:00 | 22:37:06.79 | +19:23:05.5 | HIP 111669 | 14.59 |
| 2026-03-27 00:00 | 22:37:34.67 | +19:25:00.7 | HIP 111669 | 16.71 |
| 2026-03-27 12:00 | 22:38:03.62 | +19:26:54.2 | HIP 111810 | 12.37 |
| 2026-03-28 00:00 | 22:38:33.73 | +19:28:45.7 | HIP 111810 | 5.15 |
| 2026-03-28 12:00 | 22:39:05.08 | +19:30:35.0 | HIP 111810 | 3.03 |
| 2026-03-29 00:00 | 22:39:37.75 | +19:32:21.8 | HIP 111884 | 8.78 |
| 2026-03-29 12:00 | 22:40:11.84 | +19:34:05.9 | HIP 111935 | 7.11 |
| 2026-03-30 00:00 | 22:40:47.45 | +19:35:47.0 | HIP 111935 | 9.32 |
| 2026-03-30 12:00 | 22:41:24.69 | +19:37:24.8 | HIP 111935 | 16.70 |
| 2026-03-31 00:00 | 22:42:03.68 | +19:38:58.9 | HIP 111935 | 25.45 |
| 2026-03-31 12:00 | 22:42:44.54 | +19:40:29.1 | HIP 112076 | 34.03 |
| 2026-04-01 00:00 | 22:43:27.41 | +19:41:54.8 | HIP 112358 | 34.74 |
| 2026-04-01 12:00 | 22:44:12.44 | +19:43:15.8 | HIP 112358 | 27.77 |
| 2026-04-02 00:00 | 22:44:59.78 | +19:44:31.5 | HIP 112358 | 23.51 |
| 2026-04-02 12:00 | 22:45:49.61 | +19:45:41.4 | HIP 112358 | 24.24 |
| 2026-04-03 00:00 | 22:46:42.11 | +19:46:45.2 | HIP 112535 | 13.41 |
| 2026-04-03 12:00 | 22:47:37.47 | +19:47:42.1 | HIP 112535 | 3.13 |
| 2026-04-04 00:00 | 22:48:35.91 | +19:48:31.7 | HIP 112535 | 14.18 |
| 2026-04-04 12:00 | 22:49:37.66 | +19:49:13.2 | HIP 112535 | 28.56 |
| 2026-04-05 00:00 | 22:50:42.97 | +19:49:45.9 | HIP 112927 | 25.76 |
| 2026-04-05 12:00 | 22:51:52.09 | +19:50:09.0 | HIP 112927 | 14.70 |
| 2026-04-06 00:00 | 22:53:05.32 | +19:50:21.8 | HIP 113086 | 14.95 |
| 2026-04-06 12:00 | 22:54:22.96 | +19:50:23.2 | HIP 113086 | 4.82 |
| 2026-04-07 00:00 | 22:55:45.35 | +19:50:12.2 | HIP 113173 | 19.63 |
| 2026-04-07 12:00 | 22:57:12.84 | +19:49:47.7 | HIP 113173 | 35.01 |
| 2026-04-08 00:00 | 22:58:45.82 | +19:49:08.6 | HIP 113519 | 23.14 |
| 2026-04-08 12:00 | 23:00:24.69 | +19:48:13.4 | HIP 113724 | 21.20 |
| 2026-04-09 00:00 | 23:02:09.91 | +19:47:00.7 | HIP 113724 | 4.88 |
| 2026-04-09 12:00 | 23:04:01.93 | +19:45:28.8 | HIP 113765 | 24.22 |
| 2026-04-10 00:00 | 23:06:01.29 | +19:43:36.0 | HIP 114096 | 13.17 |
| 2026-04-10 12:00 | 23:08:08.51 | +19:41:20.2 | HIP 114283 | 14.44 |
| 2026-04-11 00:00 | 23:10:24.18 | +19:38:39.2 | HIP 114283 | 23.76 |
| 2026-04-11 12:00 | 23:12:48.92 | +19:35:30.7 | HIP 114686 | 16.78 |
| 2026-04-12 00:00 | 23:15:23.39 | +19:31:51.8 | HIP 114922 | 18.81 |
| 2026-04-12 12:00 | 23:18:08.29 | +19:27:39.7 | HIP 114922 | 22.97 |
| 2026-04-13 00:00 | 23:21:04.36 | +19:22:51.0 | HIP 115207 | 14.86 |
| 2026-04-13 12:00 | 23:24:12.39 | +19:17:22.1 | HIP 115546 | 18.48 |
| 2026-04-14 00:00 | 23:27:33.19 | +19:11:08.8 | HIP 115766 | 4.82 |
| 2026-04-14 12:00 | 23:31:07.62 | +19:04:06.7 | HIP 116065 | 17.38 |
| 2026-04-15 00:00 | 23:34:56.57 | +18:56:11.0 | HIP 116518 | 29.70 |
| 2026-04-15 12:00 | 23:39:00.95 | +18:47:16.1 | HIP 116802 | 21.21 |
| 2026-04-16 00:00 | 23:43:21.70 | +18:37:16.1 | HIP 116961 | 12.24 |