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
$$ M_a = (8.602 + 5.378\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.602 |
| 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 | +7.9822 | -7.065 |
| 2012-04-20 | 2012-07-07 | +11.8613 | -8.636 |
| 2012-07-07 | 2013-03-09 | -1.6663 | -1.493 |
| 2013-03-10 | 2013-04-20 | +2.6306 | -0.220 |
| 2013-04-20 | 2014-08-27 | +0.8922 | -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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 16:19:07.74 | +16:04:24.1 | HIP 79959 | 21.30 |
| 2026-09-20 12:00 | 16:19:09.13 | +16:03:48.7 | HIP 79959 | 21.86 |
| 2026-09-21 00:00 | 16:19:10.55 | +16:03:13.4 | HIP 79959 | 22.42 |
| 2026-09-21 12:00 | 16:19:12.00 | +16:02:38.1 | HIP 79959 | 22.99 |
| 2026-09-22 00:00 | 16:19:13.48 | +16:02:03.0 | HIP 79959 | 23.56 |
| 2026-09-22 12:00 | 16:19:14.99 | +16:01:27.8 | HIP 79959 | 24.14 |
| 2026-09-23 00:00 | 16:19:16.52 | +16:00:52.8 | HIP 79959 | 24.72 |
| 2026-09-23 12:00 | 16:19:18.09 | +16:00:17.8 | HIP 79959 | 25.31 |
| 2026-09-24 00:00 | 16:19:19.68 | +15:59:42.9 | HIP 79959 | 25.90 |
| 2026-09-24 12:00 | 16:19:21.31 | +15:59:08.0 | HIP 79959 | 26.49 |
| 2026-09-25 00:00 | 16:19:22.96 | +15:58:33.3 | HIP 79959 | 27.09 |
| 2026-09-25 12:00 | 16:19:24.63 | +15:57:58.6 | HIP 79959 | 27.69 |
| 2026-09-26 00:00 | 16:19:26.34 | +15:57:24.0 | HIP 79959 | 28.30 |
| 2026-09-26 12:00 | 16:19:28.08 | +15:56:49.5 | HIP 79898 | 28.17 |
| 2026-09-27 00:00 | 16:19:29.84 | +15:56:15.1 | HIP 79898 | 27.89 |
| 2026-09-27 12:00 | 16:19:31.63 | +15:55:40.7 | HIP 79898 | 27.64 |
| 2026-09-28 00:00 | 16:19:33.45 | +15:55:06.5 | HIP 79898 | 27.41 |
| 2026-09-28 12:00 | 16:19:35.29 | +15:54:32.3 | HIP 79898 | 27.20 |
| 2026-09-29 00:00 | 16:19:37.17 | +15:53:58.3 | HIP 79898 | 27.01 |
| 2026-09-29 12:00 | 16:19:39.07 | +15:53:24.3 | HIP 79898 | 26.85 |
| 2026-09-30 00:00 | 16:19:40.99 | +15:52:50.4 | HIP 79898 | 26.71 |
| 2026-09-30 12:00 | 16:19:42.95 | +15:52:16.6 | HIP 79898 | 26.59 |
| 2026-10-01 00:00 | 16:19:44.93 | +15:51:43.0 | HIP 79898 | 26.51 |
| 2026-10-01 12:00 | 16:19:46.93 | +15:51:09.4 | HIP 79898 | 26.44 |
| 2026-10-02 00:00 | 16:19:48.97 | +15:50:36.0 | HIP 79898 | 26.41 |
| 2026-10-02 12:00 | 16:19:51.03 | +15:50:02.6 | HIP 79898 | 26.40 |
| 2026-10-03 00:00 | 16:19:53.12 | +15:49:29.4 | HIP 79898 | 26.42 |
| 2026-10-03 12:00 | 16:19:55.23 | +15:48:56.3 | HIP 79898 | 26.46 |
| 2026-10-04 00:00 | 16:19:57.37 | +15:48:23.3 | HIP 79898 | 26.53 |
| 2026-10-04 12:00 | 16:19:59.53 | +15:47:50.4 | HIP 79898 | 26.63 |
| 2026-10-05 00:00 | 16:20:01.72 | +15:47:17.6 | HIP 79898 | 26.76 |
| 2026-10-05 12:00 | 16:20:03.94 | +15:46:45.0 | HIP 79898 | 26.92 |
| 2026-10-06 00:00 | 16:20:06.18 | +15:46:12.5 | HIP 79898 | 27.10 |
| 2026-10-06 12:00 | 16:20:08.45 | +15:45:40.1 | HIP 79898 | 27.31 |
| 2026-10-07 00:00 | 16:20:10.74 | +15:45:07.8 | HIP 79898 | 27.54 |
| 2026-10-07 12:00 | 16:20:13.06 | +15:44:35.7 | HIP 79898 | 27.80 |
| 2026-10-08 00:00 | 16:20:15.40 | +15:44:03.7 | HIP 79898 | 28.09 |
| 2026-10-08 12:00 | 16:20:17.77 | +15:43:31.8 | HIP 79898 | 28.40 |
| 2026-10-09 00:00 | 16:20:20.16 | +15:43:00.1 | HIP 79898 | 28.73 |
| 2026-10-09 12:00 | 16:20:22.57 | +15:42:28.5 | HIP 79898 | 29.09 |
| 2026-10-10 00:00 | 16:20:25.01 | +15:41:57.1 | HIP 79898 | 29.47 |
| 2026-10-10 12:00 | 16:20:27.48 | +15:41:25.8 | HIP 79898 | 29.87 |
| 2026-10-11 00:00 | 16:20:29.97 | +15:40:54.6 | HIP 79898 | 30.30 |