C/2011 L4 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2011 L4 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2013-03-10T04:04:44.544000Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:31:52Z |
| Obs used | 5413 |
| NEO | - |
| M1 | 7.800 |
| K1 | 6.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2013-03-14.0000000 |
| e | 1.00003277 |
| q (au) | 0.301544 |
| a (au) | -9202.649647 |
| i (deg) | 84.208197 |
| Ω (om, deg) | 65.665886 |
| ω (w, deg) | 333.651638 |
| M (ma, deg) | 0.000004 |
Magnitude
Scatter + Global Linear
$$ M_a = (8.601 + 5.378\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.601 |
| n | 5.378 |
| gf | 1.000 |
| gb | -0.915 |
| k | 0.815 |
| δ90 | 9.995 |
| 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 |
|---|---|---|---|
| 2011-05-21 | 2012-04-20 | +7.9824 | -7.065 |
| 2012-04-20 | 2012-07-07 | +11.8617 | -8.636 |
| 2012-07-07 | 2013-03-09 | -1.6664 | -1.493 |
| 2013-03-10 | 2013-04-20 | +2.6306 | -0.220 |
| 2013-04-20 | 2014-08-27 | +0.8921 | -0.673 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 16:33:08.12 | +16:39:38.0 | HIP 81035 | 7.17 |
| 2026-03-26 12:00 | 16:33:06.42 | +16:40:12.5 | HIP 81035 | 7.66 |
| 2026-03-27 00:00 | 16:33:04.69 | +16:40:46.9 | HIP 81035 | 8.18 |
| 2026-03-27 12:00 | 16:33:02.92 | +16:41:21.3 | HIP 81035 | 8.72 |
| 2026-03-28 00:00 | 16:33:01.12 | +16:41:55.5 | HIP 81035 | 9.29 |
| 2026-03-28 12:00 | 16:32:59.29 | +16:42:29.7 | HIP 81035 | 9.87 |
| 2026-03-29 00:00 | 16:32:57.43 | +16:43:03.7 | HIP 80994 | 10.27 |
| 2026-03-29 12:00 | 16:32:55.54 | +16:43:37.7 | HIP 80994 | 9.55 |
| 2026-03-30 00:00 | 16:32:53.62 | +16:44:11.6 | HIP 80994 | 8.82 |
| 2026-03-30 12:00 | 16:32:51.67 | +16:44:45.4 | HIP 80994 | 8.09 |
| 2026-03-31 00:00 | 16:32:49.68 | +16:45:19.1 | HIP 80994 | 7.35 |
| 2026-03-31 12:00 | 16:32:47.67 | +16:45:52.7 | HIP 80994 | 6.61 |
| 2026-04-01 00:00 | 16:32:45.62 | +16:46:26.2 | HIP 80994 | 5.87 |
| 2026-04-01 12:00 | 16:32:43.55 | +16:46:59.5 | HIP 80994 | 5.13 |
| 2026-04-02 00:00 | 16:32:41.44 | +16:47:32.8 | HIP 80994 | 4.38 |
| 2026-04-02 12:00 | 16:32:39.31 | +16:48:06.0 | HIP 80994 | 3.62 |
| 2026-04-03 00:00 | 16:32:37.15 | +16:48:39.0 | HIP 80994 | 2.87 |
| 2026-04-03 12:00 | 16:32:34.95 | +16:49:11.9 | HIP 80994 | 2.11 |
| 2026-04-04 00:00 | 16:32:32.73 | +16:49:44.7 | HIP 80994 | 1.36 |
| 2026-04-04 12:00 | 16:32:30.48 | +16:50:17.4 | HIP 80994 | 0.61 |
| 2026-04-05 00:00 | 16:32:28.19 | +16:50:50.0 | HIP 80994 | 0.31 |
| 2026-04-05 12:00 | 16:32:25.88 | +16:51:22.4 | HIP 80994 | 1.00 |
| 2026-04-06 00:00 | 16:32:23.54 | +16:51:54.7 | HIP 80994 | 1.77 |
| 2026-04-06 12:00 | 16:32:21.18 | +16:52:26.9 | HIP 80994 | 2.55 |
| 2026-04-07 00:00 | 16:32:18.78 | +16:52:58.9 | HIP 80994 | 3.33 |
| 2026-04-07 12:00 | 16:32:16.35 | +16:53:30.8 | HIP 80994 | 4.11 |
| 2026-04-08 00:00 | 16:32:13.90 | +16:54:02.6 | HIP 80994 | 4.90 |
| 2026-04-08 12:00 | 16:32:11.42 | +16:54:34.2 | HIP 80994 | 5.70 |
| 2026-04-09 00:00 | 16:32:08.91 | +16:55:05.7 | HIP 80994 | 6.49 |
| 2026-04-09 12:00 | 16:32:06.38 | +16:55:37.0 | HIP 80994 | 7.29 |
| 2026-04-10 00:00 | 16:32:03.81 | +16:56:08.2 | HIP 80994 | 8.10 |
| 2026-04-10 12:00 | 16:32:01.22 | +16:56:39.2 | HIP 80994 | 8.90 |
| 2026-04-11 00:00 | 16:31:58.60 | +16:57:10.0 | HIP 80994 | 9.71 |
| 2026-04-11 12:00 | 16:31:55.96 | +16:57:40.7 | HIP 80994 | 10.53 |
| 2026-04-12 00:00 | 16:31:53.29 | +16:58:11.3 | HIP 80994 | 11.34 |
| 2026-04-12 12:00 | 16:31:50.59 | +16:58:41.7 | HIP 80994 | 12.16 |
| 2026-04-13 00:00 | 16:31:47.86 | +16:59:11.9 | HIP 80994 | 12.99 |
| 2026-04-13 12:00 | 16:31:45.11 | +16:59:41.9 | HIP 80923 | 13.31 |
| 2026-04-14 00:00 | 16:31:42.34 | +17:00:11.8 | HIP 80923 | 12.65 |
| 2026-04-14 12:00 | 16:31:39.54 | +17:00:41.5 | HIP 80923 | 12.01 |
| 2026-04-15 00:00 | 16:31:36.71 | +17:01:11.0 | HIP 80923 | 11.40 |
| 2026-04-15 12:00 | 16:31:33.86 | +17:01:40.3 | HIP 80923 | 10.83 |
| 2026-04-16 00:00 | 16:31:30.98 | +17:02:09.5 | HIP 80923 | 10.29 |