C/2017 K2 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2017 K2 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-12-19T17:27:24.742080Z |
| Orbit solution date (soln_date, UTC) | 2026-07-28T14:12:17Z |
| Obs used | 3121 |
| NEO | - |
| M1 | 8.500 |
| K1 | 4.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2021-09-09.0000000 |
| e | 1.00061578 |
| q (au) | 1.797284 |
| a (au) | -2918.712175 |
| i (deg) | 87.554842 |
| Ω (om, deg) | 88.241136 |
| ω (w, deg) | 236.192325 |
| M (ma, deg) | -0.002917 |
Magnitude
Scatter + Global Linear
$$ M_a = (8.414 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.414 |
| n | 2.000 |
| gf | 1.000 |
| gb | -0.822 |
| k | 0.988 |
| 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 | +0.2827 | -0.719 |
| 2022-05-07 | 2022-12-13 | +8.2157 | -3.820 |
| 2022-12-20 | 2024-01-29 | +5.9928 | -3.789 |
| 2024-01-29 | 2026-09-19 | +3.1796 | -2.247 |
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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 06:16:39.38 | +34:02:26.2 | HIP 29835 | 12.54 |
| 2026-09-20 12:00 | 06:16:40.39 | +34:03:15.9 | HIP 29835 | 11.69 |
| 2026-09-21 00:00 | 06:16:41.30 | +34:04:05.7 | HIP 29835 | 10.84 |
| 2026-09-21 12:00 | 06:16:42.11 | +34:04:55.7 | HIP 29835 | 9.99 |
| 2026-09-22 00:00 | 06:16:42.83 | +34:05:45.7 | HIP 29835 | 9.15 |
| 2026-09-22 12:00 | 06:16:43.44 | +34:06:35.8 | HIP 29835 | 8.32 |
| 2026-09-23 00:00 | 06:16:43.96 | +34:07:26.0 | HIP 29835 | 7.49 |
| 2026-09-23 12:00 | 06:16:44.37 | +34:08:16.3 | HIP 29835 | 6.67 |
| 2026-09-24 00:00 | 06:16:44.69 | +34:09:06.8 | HIP 29835 | 5.87 |
| 2026-09-24 12:00 | 06:16:44.90 | +34:09:57.3 | HIP 29835 | 5.09 |
| 2026-09-25 00:00 | 06:16:45.02 | +34:10:47.9 | HIP 29835 | 4.34 |
| 2026-09-25 12:00 | 06:16:45.03 | +34:11:38.5 | HIP 29835 | 3.64 |
| 2026-09-26 00:00 | 06:16:44.94 | +34:12:29.3 | HIP 29835 | 3.04 |
| 2026-09-26 12:00 | 06:16:44.75 | +34:13:20.1 | HIP 29835 | 2.59 |
| 2026-09-27 00:00 | 06:16:44.46 | +34:14:11.1 | HIP 29835 | 2.40 |
| 2026-09-27 12:00 | 06:16:44.07 | +34:15:02.1 | HIP 29835 | 2.51 |
| 2026-09-28 00:00 | 06:16:43.58 | +34:15:53.2 | HIP 29835 | 2.91 |
| 2026-09-28 12:00 | 06:16:42.99 | +34:16:44.4 | HIP 29835 | 3.49 |
| 2026-09-29 00:00 | 06:16:42.29 | +34:17:35.6 | HIP 29835 | 4.19 |
| 2026-09-29 12:00 | 06:16:41.49 | +34:18:26.9 | HIP 29835 | 4.95 |
| 2026-09-30 00:00 | 06:16:40.59 | +34:19:18.3 | HIP 29835 | 5.76 |
| 2026-09-30 12:00 | 06:16:39.58 | +34:20:09.8 | HIP 29835 | 6.60 |
| 2026-10-01 00:00 | 06:16:38.48 | +34:21:01.3 | HIP 29835 | 7.45 |
| 2026-10-01 12:00 | 06:16:37.27 | +34:21:52.9 | HIP 29835 | 8.33 |
| 2026-10-02 00:00 | 06:16:35.95 | +34:22:44.5 | HIP 29835 | 9.22 |
| 2026-10-02 12:00 | 06:16:34.53 | +34:23:36.2 | HIP 29835 | 10.12 |
| 2026-10-03 00:00 | 06:16:33.01 | +34:24:28.0 | HIP 29835 | 11.04 |
| 2026-10-03 12:00 | 06:16:31.38 | +34:25:19.8 | HIP 29835 | 11.96 |
| 2026-10-04 00:00 | 06:16:29.65 | +34:26:11.7 | HIP 29835 | 12.89 |
| 2026-10-04 12:00 | 06:16:27.82 | +34:27:03.7 | HIP 29835 | 13.84 |
| 2026-10-05 00:00 | 06:16:25.88 | +34:27:55.6 | HIP 29835 | 14.79 |
| 2026-10-05 12:00 | 06:16:23.83 | +34:28:47.7 | HIP 29835 | 15.76 |
| 2026-10-06 00:00 | 06:16:21.68 | +34:29:39.7 | HIP 29835 | 16.73 |
| 2026-10-06 12:00 | 06:16:19.43 | +34:30:31.9 | HIP 29835 | 17.72 |
| 2026-10-07 00:00 | 06:16:17.07 | +34:31:24.0 | HIP 29835 | 18.71 |
| 2026-10-07 12:00 | 06:16:14.60 | +34:32:16.2 | HIP 29835 | 19.71 |
| 2026-10-08 00:00 | 06:16:12.03 | +34:33:08.4 | HIP 29835 | 20.73 |
| 2026-10-08 12:00 | 06:16:09.35 | +34:34:00.7 | HIP 29835 | 21.75 |
| 2026-10-09 00:00 | 06:16:06.57 | +34:34:52.9 | HIP 29835 | 22.79 |
| 2026-10-09 12:00 | 06:16:03.68 | +34:35:45.3 | HIP 29835 | 23.83 |
| 2026-10-10 00:00 | 06:16:00.69 | +34:36:37.6 | HIP 29835 | 24.89 |
| 2026-10-10 12:00 | 06:15:57.59 | +34:37:29.9 | HIP 29835 | 25.96 |
| 2026-10-11 00:00 | 06:15:54.38 | +34:38:22.3 | HIP 29835 | 27.04 |