218P/LINEAR
Metadata
| Parameter | Value |
|---|---|
| Designation | 218P/LINEAR |
| Type | P |
| Perihelion (tp_cal, UTC) | 2015-04-23T12:22:13.497600Z |
| Orbit solution date (soln_date, UTC) | 2026-05-11T09:35:38Z |
| Obs used | 517 |
| NEO | Yes |
| M1 | 15.500 |
| K1 | 13.500 |
| PC | 0.030 |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2017-10-09.0000000 |
| e | 0.62196566 |
| q (au) | 1.170562 |
| a (au) | 3.096443 |
| i (deg) | 2.725398 |
| Ω (om, deg) | 176.027605 |
| ω (w, deg) | 59.673629 |
| M (ma, deg) | 162.705828 |
Magnitude
Scatter + Global Linear
$$ M_a = (14.634 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 14.634 |
| n | 6.000 |
| gf | 1.000 |
| gb | -0.500 |
| 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 |
|---|---|---|---|
| 2023-12-21 | 2026-05-15 | -9.4317 | +1.112 |
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) |
|---|---|---|---|---|
| 2026-06-01 00:00 | 23:18:06.17 | -02:06:39.0 | HIP 115091 | 13.80 |
| 2026-06-01 12:00 | 23:18:50.19 | -02:02:14.4 | HIP 115091 | 7.26 |
| 2026-06-02 00:00 | 23:19:33.77 | -01:57:52.4 | HIP 115091 | 13.89 |
| 2026-06-02 12:00 | 23:20:16.90 | -01:53:33.1 | HIP 115302 | 22.44 |
| 2026-06-03 00:00 | 23:20:59.60 | -01:49:16.5 | HIP 115302 | 13.89 |
| 2026-06-03 12:00 | 23:21:41.85 | -01:45:02.6 | HIP 115302 | 12.06 |
| 2026-06-04 00:00 | 23:22:23.65 | -01:40:51.4 | HIP 115302 | 18.80 |
| 2026-06-04 12:00 | 23:23:05.01 | -01:36:43.0 | HIP 115572 | 24.70 |
| 2026-06-05 00:00 | 23:23:45.93 | -01:32:37.3 | HIP 115572 | 17.76 |
| 2026-06-05 12:00 | 23:24:26.40 | -01:28:34.4 | HIP 115572 | 16.21 |
| 2026-06-06 00:00 | 23:25:06.42 | -01:24:34.3 | HIP 115572 | 21.06 |
| 2026-06-06 12:00 | 23:25:45.99 | -01:20:37.0 | HIP 115752 | 19.95 |
| 2026-06-07 00:00 | 23:26:25.10 | -01:16:42.6 | HIP 115752 | 9.89 |
| 2026-06-07 12:00 | 23:27:03.77 | -01:12:50.9 | HIP 115752 | 4.36 |
| 2026-06-08 00:00 | 23:27:41.99 | -01:09:02.2 | HIP 115752 | 12.41 |
| 2026-06-08 12:00 | 23:28:19.74 | -01:05:16.3 | HIP 115891 | 16.54 |
| 2026-06-09 00:00 | 23:28:57.05 | -01:01:33.3 | HIP 115951 | 8.34 |
| 2026-06-09 12:00 | 23:29:33.89 | -00:57:53.1 | HIP 115951 | 4.36 |
| 2026-06-10 00:00 | 23:30:10.28 | -00:54:16.0 | HIP 115951 | 12.72 |
| 2026-06-10 12:00 | 23:30:46.20 | -00:50:41.7 | HIP 116062 | 15.44 |
| 2026-06-11 00:00 | 23:31:21.66 | -00:47:10.4 | HIP 116062 | 12.45 |
| 2026-06-11 12:00 | 23:31:56.66 | -00:43:42.1 | HIP 116209 | 14.28 |
| 2026-06-12 00:00 | 23:32:31.19 | -00:40:16.8 | HIP 116209 | 11.00 |
| 2026-06-12 12:00 | 23:33:05.26 | -00:36:54.5 | HIP 116209 | 14.42 |
| 2026-06-13 00:00 | 23:33:38.85 | -00:33:35.2 | HIP 116320 | 10.83 |
| 2026-06-13 12:00 | 23:34:11.98 | -00:30:19.0 | HIP 116320 | 5.03 |
| 2026-06-14 00:00 | 23:34:44.63 | -00:27:05.8 | HIP 116320 | 9.48 |
| 2026-06-14 12:00 | 23:35:16.81 | -00:23:55.7 | HIP 116320 | 17.44 |
| 2026-06-15 00:00 | 23:35:48.51 | -00:20:48.7 | HIP 116320 | 25.72 |
| 2026-06-15 12:00 | 23:36:19.74 | -00:17:44.8 | HIP 116320 | 33.99 |
| 2026-06-16 00:00 | 23:36:50.48 | -00:14:44.0 | HIP 116320 | 42.17 |
| 2026-06-16 12:00 | 23:37:20.75 | -00:11:46.3 | HIP 116643 | 42.63 |
| 2026-06-17 00:00 | 23:37:50.53 | -00:08:51.8 | HIP 116643 | 43.71 |
| 2026-06-17 12:00 | 23:38:19.84 | -00:06:00.5 | HIP 116826 | 39.51 |
| 2026-06-18 00:00 | 23:38:48.66 | -00:03:12.3 | HIP 116826 | 34.67 |
| 2026-06-18 12:00 | 23:39:16.99 | -00:00:27.3 | HIP 116826 | 31.07 |
| 2026-06-19 00:00 | 23:39:44.84 | +00:02:14.5 | HIP 116823 | 26.61 |
| 2026-06-19 12:00 | 23:40:12.20 | +00:04:53.1 | HIP 116823 | 21.27 |
| 2026-06-20 00:00 | 23:40:39.08 | +00:07:28.4 | HIP 116823 | 17.49 |
| 2026-06-20 12:00 | 23:41:05.46 | +00:10:00.6 | HIP 116914 | 15.88 |
| 2026-06-21 00:00 | 23:41:31.36 | +00:12:29.5 | HIP 116914 | 13.72 |
| 2026-06-21 12:00 | 23:41:56.76 | +00:14:55.2 | HIP 116914 | 14.78 |
| 2026-06-22 00:00 | 23:42:21.67 | +00:17:17.6 | HIP 116984 | 9.19 |