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) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 07:25:55.63 | -14:49:16.8 | HIP 35995 | 12.37 |
| 2026-07-29 12:00 | 07:26:11.50 | -14:52:53.5 | HIP 35995 | 15.63 |
| 2026-07-30 00:00 | 07:26:27.22 | -14:56:31.7 | HIP 35995 | 19.75 |
| 2026-07-30 12:00 | 07:26:42.79 | -15:00:11.6 | HIP 36280 | 22.87 |
| 2026-07-31 00:00 | 07:26:58.22 | -15:03:53.0 | HIP 36280 | 21.64 |
| 2026-07-31 12:00 | 07:27:13.49 | -15:07:36.0 | HIP 36280 | 21.70 |
| 2026-08-01 00:00 | 07:27:28.62 | -15:11:20.6 | HIP 36280 | 23.02 |
| 2026-08-01 12:00 | 07:27:43.59 | -15:15:06.7 | HIP 36280 | 25.40 |
| 2026-08-02 00:00 | 07:27:58.42 | -15:18:54.4 | HIP 36395 | 27.72 |
| 2026-08-02 12:00 | 07:28:13.09 | -15:22:43.7 | HIP 36395 | 28.25 |
| 2026-08-03 00:00 | 07:28:27.61 | -15:26:34.6 | HIP 36395 | 29.74 |
| 2026-08-03 12:00 | 07:28:41.98 | -15:30:27.1 | HIP 36472 | 30.95 |
| 2026-08-04 00:00 | 07:28:56.19 | -15:34:21.2 | HIP 36472 | 25.81 |
| 2026-08-04 12:00 | 07:29:10.24 | -15:38:16.8 | HIP 36472 | 20.71 |
| 2026-08-05 00:00 | 07:29:24.15 | -15:42:14.1 | HIP 36472 | 15.68 |
| 2026-08-05 12:00 | 07:29:37.89 | -15:46:12.9 | HIP 36472 | 10.81 |
| 2026-08-06 00:00 | 07:29:51.48 | -15:50:13.3 | HIP 36472 | 6.48 |
| 2026-08-06 12:00 | 07:30:04.90 | -15:54:15.4 | HIP 36472 | 4.59 |
| 2026-08-07 00:00 | 07:30:18.17 | -15:58:19.0 | HIP 36512 | 5.41 |
| 2026-08-07 12:00 | 07:30:31.28 | -16:02:24.2 | HIP 36512 | 3.45 |
| 2026-08-08 00:00 | 07:30:44.22 | -16:06:31.0 | HIP 36512 | 6.93 |
| 2026-08-08 12:00 | 07:30:57.00 | -16:10:39.4 | HIP 36512 | 11.73 |
| 2026-08-09 00:00 | 07:31:09.62 | -16:14:49.4 | HIP 36512 | 16.75 |
| 2026-08-09 12:00 | 07:31:22.07 | -16:19:00.9 | HIP 36512 | 21.84 |
| 2026-08-10 00:00 | 07:31:34.35 | -16:23:14.1 | HIP 36512 | 26.95 |
| 2026-08-10 12:00 | 07:31:46.46 | -16:27:28.9 | HIP 36670 | 25.25 |
| 2026-08-11 00:00 | 07:31:58.40 | -16:31:45.2 | HIP 36670 | 20.12 |
| 2026-08-11 12:00 | 07:32:10.17 | -16:36:03.1 | HIP 36670 | 15.01 |
| 2026-08-12 00:00 | 07:32:21.77 | -16:40:22.7 | HIP 36670 | 9.91 |
| 2026-08-12 12:00 | 07:32:33.19 | -16:44:43.7 | HIP 36670 | 4.90 |
| 2026-08-13 00:00 | 07:32:44.44 | -16:49:06.4 | HIP 36670 | 1.57 |
| 2026-08-13 12:00 | 07:32:55.51 | -16:53:30.7 | HIP 36670 | 5.79 |
| 2026-08-14 00:00 | 07:33:06.40 | -16:57:56.5 | HIP 36670 | 10.83 |
| 2026-08-14 12:00 | 07:33:17.11 | -17:02:23.8 | HIP 36670 | 15.93 |
| 2026-08-15 00:00 | 07:33:27.63 | -17:06:52.7 | HIP 36881 | 20.83 |
| 2026-08-15 12:00 | 07:33:37.97 | -17:11:23.2 | HIP 36881 | 18.90 |
| 2026-08-16 00:00 | 07:33:48.13 | -17:15:55.2 | HIP 36881 | 18.32 |
| 2026-08-16 12:00 | 07:33:58.10 | -17:20:28.8 | HIP 36881 | 19.21 |
| 2026-08-17 00:00 | 07:34:07.89 | -17:25:03.9 | HIP 36901 | 17.24 |
| 2026-08-17 12:00 | 07:34:17.48 | -17:29:40.5 | HIP 36901 | 13.46 |
| 2026-08-18 00:00 | 07:34:26.89 | -17:34:18.6 | HIP 36901 | 10.91 |
| 2026-08-18 12:00 | 07:34:36.10 | -17:38:58.3 | HIP 36901 | 10.54 |
| 2026-08-19 00:00 | 07:34:45.12 | -17:43:39.5 | HIP 36901 | 12.54 |