C/2025 R3 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2025 R3 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2026-04-19T21:27:46.638720Z |
| Orbit solution date (soln_date, UTC) | 2026-07-06T12:12:29Z |
| Obs used | 899 |
| NEO | - |
| M1 | 11.700 |
| 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) | 2026-01-23.0000000 |
| e | 1.00035013 |
| q (au) | 0.498612 |
| a (au) | -1424.073110 |
| i (deg) | 124.730994 |
| Ω (om, deg) | 38.693543 |
| ω (w, deg) | 162.225603 |
| M (ma, deg) | -0.001594 |
Magnitude
Scatter + Global Linear
$$ M_a = (11.104 + 5.313\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 11.104 |
| n | 5.313 |
| 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 | -1.1549 | +0.599 |
| 2026-01-11 | 2026-03-27 | +3.3446 | -1.334 |
| 2026-03-27 | 2026-04-19 | -1.6312 | -1.429 |
| 2026-04-20 | 2026-05-19 | -17.2431 | -4.831 |
| 2026-05-19 | 2026-05-26 | +9.4956 | -2.639 |
| 2026-05-26 | 2026-06-25 | +3.1313 | -3.045 |
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) |
|---|---|---|---|---|
| 2026-09-25 00:00 | 07:34:56.81 | -24:33:00.6 | HIP 37006 | 18.83 |
| 2026-09-25 12:00 | 07:34:46.14 | -24:39:12.6 | HIP 37006 | 21.07 |
| 2026-09-26 00:00 | 07:34:35.11 | -24:45:25.2 | HIP 36721 | 19.57 |
| 2026-09-26 12:00 | 07:34:23.74 | -24:51:38.3 | HIP 36721 | 19.04 |
| 2026-09-27 00:00 | 07:34:12.02 | -24:57:52.1 | HIP 36721 | 20.76 |
| 2026-09-27 12:00 | 07:33:59.94 | -25:04:06.4 | HIP 36721 | 24.29 |
| 2026-09-28 00:00 | 07:33:47.51 | -25:10:21.3 | HIP 36929 | 26.65 |
| 2026-09-28 12:00 | 07:33:34.72 | -25:16:36.6 | HIP 36929 | 26.90 |
| 2026-09-29 00:00 | 07:33:21.57 | -25:22:52.4 | HIP 36929 | 28.93 |
| 2026-09-29 12:00 | 07:33:08.06 | -25:29:08.7 | HIP 36929 | 32.42 |
| 2026-09-30 00:00 | 07:32:54.19 | -25:35:25.4 | HIP 36929 | 36.99 |
| 2026-09-30 12:00 | 07:32:39.95 | -25:41:42.5 | HIP 36837 | 35.21 |
| 2026-10-01 00:00 | 07:32:25.33 | -25:48:00.0 | HIP 36837 | 33.65 |
| 2026-10-01 12:00 | 07:32:10.35 | -25:54:17.7 | HIP 36837 | 33.62 |
| 2026-10-02 00:00 | 07:31:54.99 | -26:00:35.8 | HIP 36469 | 30.39 |
| 2026-10-02 12:00 | 07:31:39.25 | -26:06:54.2 | HIP 36469 | 23.63 |
| 2026-10-03 00:00 | 07:31:23.13 | -26:13:12.8 | HIP 36469 | 17.20 |
| 2026-10-03 12:00 | 07:31:06.63 | -26:19:31.6 | HIP 36469 | 11.70 |
| 2026-10-04 00:00 | 07:30:49.75 | -26:25:50.6 | HIP 36469 | 9.16 |
| 2026-10-04 12:00 | 07:30:32.47 | -26:32:09.8 | HIP 36469 | 11.78 |
| 2026-10-05 00:00 | 07:30:14.81 | -26:38:29.0 | HIP 36469 | 17.42 |
| 2026-10-05 12:00 | 07:29:56.75 | -26:44:48.4 | HIP 36359 | 18.77 |
| 2026-10-06 00:00 | 07:29:38.30 | -26:51:07.7 | HIP 36359 | 11.30 |
| 2026-10-06 12:00 | 07:29:19.45 | -26:57:27.1 | HIP 36359 | 4.06 |
| 2026-10-07 00:00 | 07:29:00.20 | -27:03:46.4 | HIP 36359 | 4.55 |
| 2026-10-07 12:00 | 07:28:40.54 | -27:10:05.6 | HIP 36274 | 8.40 |
| 2026-10-08 00:00 | 07:28:20.48 | -27:16:24.7 | HIP 36274 | 4.89 |
| 2026-10-08 12:00 | 07:28:00.01 | -27:22:43.6 | HIP 36267 | 0.97 |
| 2026-10-09 00:00 | 07:27:39.14 | -27:29:02.3 | HIP 36267 | 8.80 |
| 2026-10-09 12:00 | 07:27:17.85 | -27:35:20.8 | HIP 36293 | 16.59 |
| 2026-10-10 00:00 | 07:26:56.14 | -27:41:38.9 | HIP 36118 | 17.97 |
| 2026-10-10 12:00 | 07:26:34.02 | -27:47:56.7 | HIP 36118 | 10.47 |
| 2026-10-11 00:00 | 07:26:11.49 | -27:54:14.1 | HIP 36118 | 4.89 |
| 2026-10-11 12:00 | 07:25:48.53 | -28:00:31.1 | HIP 36118 | 8.26 |
| 2026-10-12 00:00 | 07:25:25.15 | -28:06:47.6 | HIP 36009 | 4.83 |
| 2026-10-12 12:00 | 07:25:01.35 | -28:13:03.6 | HIP 36009 | 3.79 |
| 2026-10-13 00:00 | 07:24:37.12 | -28:19:18.9 | HIP 36009 | 11.85 |
| 2026-10-13 12:00 | 07:24:12.46 | -28:25:33.7 | HIP 35870 | 6.56 |
| 2026-10-14 00:00 | 07:23:47.38 | -28:31:47.7 | HIP 35870 | 7.19 |
| 2026-10-14 12:00 | 07:23:21.87 | -28:38:01.0 | HIP 35870 | 14.12 |
| 2026-10-15 00:00 | 07:22:55.92 | -28:44:13.6 | HIP 35906 | 16.71 |
| 2026-10-15 12:00 | 07:22:29.55 | -28:50:25.3 | HIP 35906 | 21.57 |
| 2026-10-16 00:00 | 07:22:02.73 | -28:56:36.1 | HIP 35630 | 22.47 |