217P/LINEAR
Metadata
| Parameter | Value |
|---|---|
| Designation | 217P/LINEAR |
| Type | P |
| Perihelion (tp_cal, UTC) | 2009-09-08T20:48:22.847040Z |
| Orbit solution date (soln_date, UTC) | 2026-01-13T17:41:01Z |
| Obs used | 3182 |
| NEO | Yes |
| M1 | 14.300 |
| K1 | 6.000 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2012-06-24.0000000 |
| e | 0.68914848 |
| q (au) | 1.227442 |
| a (au) | 3.948642 |
| i (deg) | 12.865833 |
| Ω (om, deg) | 125.566275 |
| ω (w, deg) | 246.899356 |
| M (ma, deg) | 128.015708 |
Magnitude
Scatter + Global Linear
$$ M_a = (9.028 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 9.028 |
| n | 6.000 |
| gf | 1.000 |
| gb | -0.510 |
| k | 1.000 |
| 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 |
|---|---|---|---|
| 2024-05-01 | 2025-05-24 | -11.7875 | +1.198 |
| 2025-05-24 | 2026-01-05 | +3.9061 | -0.915 |
| 2026-01-05 | 2026-01-22 | -2.9532 | +1.780 |
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) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 08:31:50.73 | +19:51:13.5 | HIP 41903 | 21.00 |
| 2026-02-03 12:00 | 08:31:21.06 | +19:54:34.4 | HIP 41903 | 23.28 |
| 2026-02-04 00:00 | 08:30:51.60 | +19:57:53.6 | HIP 41903 | 27.59 |
| 2026-02-04 12:00 | 08:30:22.35 | +20:01:11.2 | HIP 41638 | 27.78 |
| 2026-02-05 00:00 | 08:29:53.30 | +20:04:27.0 | HIP 41638 | 22.19 |
| 2026-02-05 12:00 | 08:29:24.48 | +20:07:41.0 | HIP 41638 | 18.11 |
| 2026-02-06 00:00 | 08:28:55.89 | +20:10:53.4 | HIP 41638 | 16.62 |
| 2026-02-06 12:00 | 08:28:27.52 | +20:14:03.9 | HIP 41638 | 18.27 |
| 2026-02-07 00:00 | 08:27:59.39 | +20:17:12.6 | HIP 41638 | 22.32 |
| 2026-02-07 12:00 | 08:27:31.51 | +20:20:19.5 | HIP 41334 | 23.33 |
| 2026-02-08 00:00 | 08:27:03.88 | +20:23:24.6 | HIP 41334 | 19.21 |
| 2026-02-08 12:00 | 08:26:36.50 | +20:26:27.8 | HIP 41334 | 17.23 |
| 2026-02-09 00:00 | 08:26:09.38 | +20:29:29.2 | HIP 41334 | 18.04 |
| 2026-02-09 12:00 | 08:25:42.53 | +20:32:28.7 | HIP 41334 | 21.24 |
| 2026-02-10 00:00 | 08:25:15.95 | +20:35:26.3 | HIP 41334 | 25.90 |
| 2026-02-10 12:00 | 08:24:49.65 | +20:38:22.1 | HIP 41083 | 26.80 |
| 2026-02-11 00:00 | 08:24:23.63 | +20:41:15.9 | HIP 41083 | 21.58 |
| 2026-02-11 12:00 | 08:23:57.89 | +20:44:07.8 | HIP 41083 | 17.47 |
| 2026-02-12 00:00 | 08:23:32.45 | +20:46:57.7 | HIP 41083 | 15.31 |
| 2026-02-12 12:00 | 08:23:07.30 | +20:49:45.7 | HIP 41083 | 15.80 |
| 2026-02-13 00:00 | 08:22:42.46 | +20:52:31.8 | HIP 41083 | 18.66 |
| 2026-02-13 12:00 | 08:22:17.92 | +20:55:15.9 | HIP 41083 | 22.95 |
| 2026-02-14 00:00 | 08:21:53.69 | +20:57:58.1 | HIP 40866 | 25.32 |
| 2026-02-14 12:00 | 08:21:29.78 | +21:00:38.3 | HIP 40866 | 22.52 |
| 2026-02-15 00:00 | 08:21:06.19 | +21:03:16.5 | HIP 40807 | 20.93 |
| 2026-02-15 12:00 | 08:20:42.91 | +21:05:52.7 | HIP 40807 | 17.54 |
| 2026-02-16 00:00 | 08:20:19.97 | +21:08:27.0 | HIP 40781 | 14.80 |
| 2026-02-16 12:00 | 08:19:57.35 | +21:10:59.2 | HIP 40781 | 8.96 |
| 2026-02-17 00:00 | 08:19:35.07 | +21:13:29.5 | HIP 40781 | 3.24 |
| 2026-02-17 12:00 | 08:19:13.13 | +21:15:57.8 | HIP 40781 | 2.58 |
| 2026-02-18 00:00 | 08:18:51.53 | +21:18:24.1 | HIP 40781 | 8.12 |
| 2026-02-18 12:00 | 08:18:30.27 | +21:20:48.4 | HIP 40650 | 13.46 |
| 2026-02-19 00:00 | 08:18:09.36 | +21:23:10.7 | HIP 40650 | 13.13 |
| 2026-02-19 12:00 | 08:17:48.80 | +21:25:31.0 | HIP 40650 | 14.88 |
| 2026-02-20 00:00 | 08:17:28.60 | +21:27:49.3 | HIP 40544 | 17.19 |
| 2026-02-20 12:00 | 08:17:08.75 | +21:30:05.6 | HIP 40544 | 17.11 |
| 2026-02-21 00:00 | 08:16:49.25 | +21:32:19.9 | HIP 40544 | 18.49 |
| 2026-02-21 12:00 | 08:16:30.12 | +21:34:32.3 | HIP 40544 | 20.98 |
| 2026-02-22 00:00 | 08:16:11.35 | +21:36:42.6 | HIP 40565 | 21.26 |
| 2026-02-22 12:00 | 08:15:52.95 | +21:38:51.0 | HIP 40565 | 22.04 |
| 2026-02-23 00:00 | 08:15:34.91 | +21:40:57.4 | HIP 40325 | 21.42 |
| 2026-02-23 12:00 | 08:15:17.24 | +21:43:01.8 | HIP 40325 | 17.54 |
| 2026-02-24 00:00 | 08:14:59.93 | +21:45:04.3 | HIP 40325 | 14.18 |