C/2025 R3 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2025 R3 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2026-04-19T21:27:51.088320Z |
| Orbit solution date (soln_date, UTC) | 2026-05-28T12:12:16Z |
| Obs used | 862 |
| NEO | - |
| M1 | 11.800 |
| K1 | 11.250 |
| 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) | 2026-01-17.0000000 |
| e | 1.00034935 |
| q (au) | 0.498612 |
| a (au) | -1427.254832 |
| i (deg) | 124.730925 |
| Ω (om, deg) | 38.693471 |
| ω (w, deg) | 162.225628 |
| M (ma, deg) | -0.001698 |
Magnitude
Scatter + Global Linear
$$ M_a = (11.151 + 5.337\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 11.151 |
| n | 5.337 |
| gf | 0.800 |
| gb | -0.500 |
| k | 0.800 |
| δ90 | 1.000 |
| 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 | -1.2130 | +0.552 |
| 2026-01-11 | 2026-03-27 | +3.2865 | -1.382 |
| 2026-03-27 | 2026-04-19 | -1.6894 | -1.477 |
| 2026-04-20 | 2026-05-15 | -18.4552 | -5.196 |
| 2026-05-15 | 2026-06-07 | -2.4882 | -3.299 |
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 | 06:35:05.20 | -10:31:47.3 | HIP 31456 | 5.68 |
| 2026-06-01 12:00 | 06:35:51.10 | -10:33:18.2 | HIP 31496 | 5.78 |
| 2026-06-02 00:00 | 06:36:36.16 | -10:34:47.6 | HIP 31496 | 14.17 |
| 2026-06-02 12:00 | 06:37:20.43 | -10:36:15.7 | HIP 31496 | 24.67 |
| 2026-06-03 00:00 | 06:38:03.93 | -10:37:42.7 | HIP 31855 | 27.08 |
| 2026-06-03 12:00 | 06:38:46.70 | -10:39:08.6 | HIP 31855 | 18.23 |
| 2026-06-04 00:00 | 06:39:28.76 | -10:40:33.6 | HIP 31855 | 12.54 |
| 2026-06-04 12:00 | 06:40:10.15 | -10:41:57.9 | HIP 31855 | 14.03 |
| 2026-06-05 00:00 | 06:40:50.89 | -10:43:21.5 | HIP 31855 | 21.01 |
| 2026-06-05 12:00 | 06:41:31.01 | -10:44:44.7 | HIP 32131 | 16.22 |
| 2026-06-06 00:00 | 06:42:10.52 | -10:46:07.4 | HIP 32131 | 6.62 |
| 2026-06-06 12:00 | 06:42:49.46 | -10:47:29.9 | HIP 32131 | 3.95 |
| 2026-06-07 00:00 | 06:43:27.83 | -10:48:52.1 | HIP 32131 | 13.06 |
| 2026-06-07 12:00 | 06:44:05.67 | -10:50:14.3 | HIP 32255 | 9.77 |
| 2026-06-08 00:00 | 06:44:42.99 | -10:51:36.4 | HIP 32255 | 11.77 |
| 2026-06-08 12:00 | 06:45:19.81 | -10:52:58.6 | HIP 32255 | 18.68 |
| 2026-06-09 00:00 | 06:45:56.15 | -10:54:20.9 | HIP 32255 | 26.83 |
| 2026-06-09 12:00 | 06:46:32.02 | -10:55:43.5 | HIP 32585 | 23.55 |
| 2026-06-10 00:00 | 06:47:07.45 | -10:57:06.4 | HIP 32585 | 15.44 |
| 2026-06-10 12:00 | 06:47:42.43 | -10:58:29.6 | HIP 32585 | 8.81 |
| 2026-06-11 00:00 | 06:48:17.00 | -10:59:53.3 | HIP 32585 | 8.18 |
| 2026-06-11 12:00 | 06:48:51.16 | -11:01:17.4 | HIP 32641 | 11.21 |
| 2026-06-12 00:00 | 06:49:24.92 | -11:02:42.1 | HIP 32641 | 17.27 |
| 2026-06-12 12:00 | 06:49:58.30 | -11:04:07.4 | HIP 32641 | 24.67 |
| 2026-06-13 00:00 | 06:50:31.31 | -11:05:33.4 | HIP 32971 | 23.33 |
| 2026-06-13 12:00 | 06:51:03.96 | -11:07:00.1 | HIP 32971 | 15.27 |
| 2026-06-14 00:00 | 06:51:36.26 | -11:08:27.5 | HIP 32971 | 7.46 |
| 2026-06-14 12:00 | 06:52:08.23 | -11:09:55.8 | HIP 32971 | 2.74 |
| 2026-06-15 00:00 | 06:52:39.86 | -11:11:24.9 | HIP 32971 | 9.22 |
| 2026-06-15 12:00 | 06:53:11.16 | -11:12:54.8 | HIP 33075 | 1.68 |
| 2026-06-16 00:00 | 06:53:42.16 | -11:14:25.7 | HIP 33112 | 1.94 |
| 2026-06-16 12:00 | 06:54:12.85 | -11:15:57.6 | HIP 33112 | 6.17 |
| 2026-06-17 00:00 | 06:54:43.25 | -11:17:30.4 | HIP 33112 | 13.73 |
| 2026-06-17 12:00 | 06:55:13.35 | -11:19:04.3 | HIP 33336 | 17.48 |
| 2026-06-18 00:00 | 06:55:43.17 | -11:20:39.2 | HIP 33336 | 12.39 |
| 2026-06-18 12:00 | 06:56:12.71 | -11:22:15.1 | HIP 33336 | 10.59 |
| 2026-06-19 00:00 | 06:56:41.99 | -11:23:52.2 | HIP 33336 | 13.39 |
| 2026-06-19 12:00 | 06:57:11.00 | -11:25:30.3 | HIP 33457 | 18.62 |
| 2026-06-20 00:00 | 06:57:39.75 | -11:27:09.7 | HIP 33567 | 11.88 |
| 2026-06-20 12:00 | 06:58:08.26 | -11:28:50.1 | HIP 33567 | 5.67 |
| 2026-06-21 00:00 | 06:58:36.51 | -11:30:31.8 | HIP 33569 | 5.00 |
| 2026-06-21 12:00 | 06:59:04.53 | -11:32:14.6 | HIP 33569 | 10.74 |
| 2026-06-22 00:00 | 06:59:32.31 | -11:33:58.6 | HIP 33569 | 17.44 |