C/2017 K2 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2017 K2 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-12-19T17:27:52.640640Z |
| Orbit solution date (soln_date, UTC) | 2026-03-31T09:42:18Z |
| Obs used | 3105 |
| NEO | - |
| M1 | 8.500 |
| K1 | 4.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2021-09-08.0000000 |
| e | 1.00061511 |
| q (au) | 1.797287 |
| a (au) | -2921.901251 |
| i (deg) | 87.554809 |
| Ω (om, deg) | 88.241180 |
| ω (w, deg) | 236.192288 |
| M (ma, deg) | -0.002919 |
Magnitude
Scatter + Global Linear
$$ M_a = (8.405 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.405 |
| n | 2.000 |
| gf | 0.995 |
| gb | -0.824 |
| k | 0.989 |
| δ90 | 10.000 |
| 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 |
|---|---|---|---|
| 2013-05-12 | 2022-05-07 | +0.3103 | -0.737 |
| 2022-05-07 | 2022-12-13 | +8.2101 | -3.820 |
| 2022-12-20 | 2024-01-29 | +6.0152 | -3.801 |
| 2024-01-29 | 2026-03-21 | +3.2681 | -2.311 |
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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 05:29:07.04 | +31:19:10.6 | HIP 25711 | 7.42 |
| 2026-03-26 12:00 | 05:29:09.91 | +31:19:18.7 | HIP 25711 | 7.01 |
| 2026-03-27 00:00 | 05:29:12.88 | +31:19:26.8 | HIP 25711 | 6.63 |
| 2026-03-27 12:00 | 05:29:15.95 | +31:19:35.1 | HIP 25711 | 6.28 |
| 2026-03-28 00:00 | 05:29:19.11 | +31:19:43.4 | HIP 25711 | 5.97 |
| 2026-03-28 12:00 | 05:29:22.38 | +31:19:51.8 | HIP 25711 | 5.74 |
| 2026-03-29 00:00 | 05:29:25.74 | +31:20:00.4 | HIP 25711 | 5.58 |
| 2026-03-29 12:00 | 05:29:29.20 | +31:20:09.0 | HIP 25711 | 5.52 |
| 2026-03-30 00:00 | 05:29:32.75 | +31:20:17.7 | HIP 25711 | 5.56 |
| 2026-03-30 12:00 | 05:29:36.40 | +31:20:26.5 | HIP 25711 | 5.72 |
| 2026-03-31 00:00 | 05:29:40.14 | +31:20:35.4 | HIP 25711 | 5.99 |
| 2026-03-31 12:00 | 05:29:43.98 | +31:20:44.4 | HIP 25711 | 6.36 |
| 2026-04-01 00:00 | 05:29:47.91 | +31:20:53.6 | HIP 25711 | 6.83 |
| 2026-04-01 12:00 | 05:29:51.94 | +31:21:02.8 | HIP 25711 | 7.38 |
| 2026-04-02 00:00 | 05:29:56.05 | +31:21:12.1 | HIP 25711 | 8.01 |
| 2026-04-02 12:00 | 05:30:00.26 | +31:21:21.5 | HIP 25794 | 7.50 |
| 2026-04-03 00:00 | 05:30:04.56 | +31:21:31.0 | HIP 25794 | 6.88 |
| 2026-04-03 12:00 | 05:30:08.96 | +31:21:40.6 | HIP 25794 | 6.33 |
| 2026-04-04 00:00 | 05:30:13.44 | +31:21:50.3 | HIP 25794 | 5.88 |
| 2026-04-04 12:00 | 05:30:18.01 | +31:22:00.2 | HIP 25794 | 5.55 |
| 2026-04-05 00:00 | 05:30:22.67 | +31:22:10.1 | HIP 25794 | 5.38 |
| 2026-04-05 12:00 | 05:30:27.42 | +31:22:20.1 | HIP 25794 | 5.41 |
| 2026-04-06 00:00 | 05:30:32.26 | +31:22:30.2 | HIP 25794 | 5.62 |
| 2026-04-06 12:00 | 05:30:37.18 | +31:22:40.5 | HIP 25794 | 6.03 |
| 2026-04-07 00:00 | 05:30:42.20 | +31:22:50.8 | HIP 25794 | 6.59 |
| 2026-04-07 12:00 | 05:30:47.30 | +31:23:01.3 | HIP 25794 | 7.28 |
| 2026-04-08 00:00 | 05:30:52.48 | +31:23:11.8 | HIP 25794 | 8.08 |
| 2026-04-08 12:00 | 05:30:57.75 | +31:23:22.5 | HIP 25801 | 8.65 |
| 2026-04-09 00:00 | 05:31:03.11 | +31:23:33.2 | HIP 25801 | 9.17 |
| 2026-04-09 12:00 | 05:31:08.55 | +31:23:44.1 | HIP 25801 | 9.82 |
| 2026-04-10 00:00 | 05:31:14.07 | +31:23:55.0 | HIP 25801 | 10.57 |
| 2026-04-10 12:00 | 05:31:19.68 | +31:24:06.1 | HIP 25801 | 11.41 |
| 2026-04-11 00:00 | 05:31:25.37 | +31:24:17.3 | HIP 25801 | 12.32 |
| 2026-04-11 12:00 | 05:31:31.15 | +31:24:28.6 | HIP 25801 | 13.30 |
| 2026-04-12 00:00 | 05:31:37.00 | +31:24:40.0 | HIP 25801 | 14.34 |
| 2026-04-12 12:00 | 05:31:42.93 | +31:24:51.5 | HIP 25801 | 15.42 |
| 2026-04-13 00:00 | 05:31:48.95 | +31:25:03.1 | HIP 25801 | 16.55 |
| 2026-04-13 12:00 | 05:31:55.05 | +31:25:14.8 | HIP 25801 | 17.72 |
| 2026-04-14 00:00 | 05:32:01.22 | +31:25:26.7 | HIP 25801 | 18.92 |
| 2026-04-14 12:00 | 05:32:07.48 | +31:25:38.6 | HIP 25801 | 20.16 |
| 2026-04-15 00:00 | 05:32:13.81 | +31:25:50.7 | HIP 25801 | 21.42 |
| 2026-04-15 12:00 | 05:32:20.22 | +31:26:02.8 | HIP 25801 | 22.71 |
| 2026-04-16 00:00 | 05:32:26.70 | +31:26:15.1 | HIP 25801 | 24.03 |