C/2017 K2 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2017 K2 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-12-19T17:27:53.064000Z |
| Orbit solution date (soln_date, UTC) | 2026-04-27T13:42:20Z |
| Obs used | 3106 |
| NEO | - |
| M1 | 8.500 |
| K1 | 4.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2021-09-08.0000000 |
| e | 1.00061514 |
| q (au) | 1.797287 |
| a (au) | -2921.753852 |
| i (deg) | 87.554809 |
| Ω (om, deg) | 88.241180 |
| ω (w, deg) | 236.192285 |
| 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 | 1.000 |
| 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 | +0.3104 | -0.737 |
| 2022-05-07 | 2022-12-13 | +8.2108 | -3.820 |
| 2022-12-20 | 2024-01-29 | +6.0166 | -3.802 |
| 2024-01-29 | 2026-03-21 | +3.2524 | -2.299 |
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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 05:39:33.61 | +31:39:21.7 | HIP 26570 | 18.37 |
| 2026-05-12 12:00 | 05:39:43.24 | +31:39:39.7 | HIP 26570 | 19.58 |
| 2026-05-13 00:00 | 05:39:52.92 | +31:39:57.7 | HIP 26718 | 18.50 |
| 2026-05-13 12:00 | 05:40:02.64 | +31:40:15.9 | HIP 26718 | 17.16 |
| 2026-05-14 00:00 | 05:40:12.40 | +31:40:34.1 | HIP 26718 | 15.96 |
| 2026-05-14 12:00 | 05:40:22.20 | +31:40:52.5 | HIP 26718 | 14.97 |
| 2026-05-15 00:00 | 05:40:32.04 | +31:41:10.9 | HIP 26718 | 14.21 |
| 2026-05-15 12:00 | 05:40:41.92 | +31:41:29.5 | HIP 26718 | 13.75 |
| 2026-05-16 00:00 | 05:40:51.85 | +31:41:48.2 | HIP 26718 | 13.59 |
| 2026-05-16 12:00 | 05:41:01.81 | +31:42:06.9 | HIP 26718 | 13.78 |
| 2026-05-17 00:00 | 05:41:11.80 | +31:42:25.8 | HIP 26718 | 14.28 |
| 2026-05-17 12:00 | 05:41:21.84 | +31:42:44.8 | HIP 26863 | 14.46 |
| 2026-05-18 00:00 | 05:41:31.91 | +31:43:03.9 | HIP 26863 | 12.71 |
| 2026-05-18 12:00 | 05:41:42.01 | +31:43:23.0 | HIP 26863 | 11.10 |
| 2026-05-19 00:00 | 05:41:52.16 | +31:43:42.3 | HIP 26863 | 9.71 |
| 2026-05-19 12:00 | 05:42:02.33 | +31:44:01.7 | HIP 26863 | 8.65 |
| 2026-05-20 00:00 | 05:42:12.54 | +31:44:21.2 | HIP 26863 | 8.05 |
| 2026-05-20 12:00 | 05:42:22.78 | +31:44:40.8 | HIP 26863 | 8.02 |
| 2026-05-21 00:00 | 05:42:33.06 | +31:45:00.5 | HIP 26863 | 8.59 |
| 2026-05-21 12:00 | 05:42:43.36 | +31:45:20.3 | HIP 26863 | 9.64 |
| 2026-05-22 00:00 | 05:42:53.70 | +31:45:40.2 | HIP 26863 | 11.04 |
| 2026-05-22 12:00 | 05:43:04.07 | +31:46:00.2 | HIP 26863 | 12.68 |
| 2026-05-23 00:00 | 05:43:14.47 | +31:46:20.3 | HIP 26863 | 14.49 |
| 2026-05-23 12:00 | 05:43:24.89 | +31:46:40.5 | HIP 26863 | 16.41 |
| 2026-05-24 00:00 | 05:43:35.35 | +31:47:00.8 | HIP 26863 | 18.40 |
| 2026-05-24 12:00 | 05:43:45.83 | +31:47:21.2 | HIP 26863 | 20.45 |
| 2026-05-25 00:00 | 05:43:56.34 | +31:47:41.7 | HIP 26863 | 22.55 |
| 2026-05-25 12:00 | 05:44:06.87 | +31:48:02.3 | HIP 27066 | 22.63 |
| 2026-05-26 00:00 | 05:44:17.43 | +31:48:23.0 | HIP 27066 | 22.06 |
| 2026-05-26 12:00 | 05:44:28.02 | +31:48:43.8 | HIP 27066 | 21.70 |
| 2026-05-27 00:00 | 05:44:38.63 | +31:49:04.7 | HIP 27066 | 21.58 |
| 2026-05-27 12:00 | 05:44:49.27 | +31:49:25.8 | HIP 27066 | 21.70 |
| 2026-05-28 00:00 | 05:44:59.92 | +31:49:46.9 | HIP 27066 | 22.05 |
| 2026-05-28 12:00 | 05:45:10.61 | +31:50:08.1 | HIP 27066 | 22.64 |
| 2026-05-29 00:00 | 05:45:21.31 | +31:50:29.4 | HIP 27163 | 23.24 |
| 2026-05-29 12:00 | 05:45:32.04 | +31:50:50.8 | HIP 27163 | 22.83 |
| 2026-05-30 00:00 | 05:45:42.78 | +31:51:12.3 | HIP 27163 | 22.64 |
| 2026-05-30 12:00 | 05:45:53.55 | +31:51:33.9 | HIP 27163 | 22.69 |
| 2026-05-31 00:00 | 05:46:04.34 | +31:51:55.7 | HIP 27163 | 22.97 |
| 2026-05-31 12:00 | 05:46:15.15 | +31:52:17.5 | HIP 27163 | 23.48 |
| 2026-06-01 00:00 | 05:46:25.97 | +31:52:39.4 | HIP 27163 | 24.20 |
| 2026-06-01 12:00 | 05:46:36.82 | +31:53:01.4 | HIP 27163 | 25.11 |
| 2026-06-02 00:00 | 05:46:47.68 | +31:53:23.5 | HIP 27163 | 26.20 |