217P/LINEAR
Metadata
| Parameter | Value |
|---|---|
| Designation | 217P/LINEAR |
| Type | P |
| Perihelion (tp_cal, UTC) | 2009-09-08T15:10:27.419520Z |
| Orbit solution date (soln_date, UTC) | 2026-04-30T15:30:22Z |
| Obs used | 3359 |
| NEO | Yes |
| M1 | 14.500 |
| K1 | 4.750 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2013-01-14.0000000 |
| e | 0.68880769 |
| q (au) | 1.229097 |
| a (au) | 3.949637 |
| i (deg) | 12.861440 |
| Ω (om, deg) | 125.536330 |
| ω (w, deg) | 246.943590 |
| M (ma, deg) | 153.612051 |
Magnitude
Scatter + Global Linear
$$ M_a = (9.156 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 9.156 |
| n | 6.000 |
| gf | 1.000 |
| gb | -1.000 |
| 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 | 2025-11-02 | +4.3232 | -1.044 |
| 2025-11-02 | 2025-12-19 | +3.3275 | -0.618 |
| 2025-12-19 | 2026-02-14 | -38.2327 | +17.066 |
| 2026-02-14 | 2026-04-06 | +21.1541 | -12.161 |
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 | 08:33:33.85 | +22:12:00.1 | HIP 41891 | 19.02 |
| 2026-05-12 12:00 | 08:33:58.01 | +22:10:52.2 | HIP 42056 | 20.26 |
| 2026-05-13 00:00 | 08:34:22.29 | +22:09:43.7 | HIP 42056 | 20.77 |
| 2026-05-13 12:00 | 08:34:46.69 | +22:08:34.4 | HIP 42056 | 22.77 |
| 2026-05-14 00:00 | 08:35:11.22 | +22:07:24.3 | HIP 42235 | 20.77 |
| 2026-05-14 12:00 | 08:35:35.85 | +22:06:13.6 | HIP 42235 | 15.42 |
| 2026-05-15 00:00 | 08:36:00.61 | +22:05:02.2 | HIP 42235 | 10.57 |
| 2026-05-15 12:00 | 08:36:25.48 | +22:03:50.1 | HIP 42235 | 7.36 |
| 2026-05-16 00:00 | 08:36:50.46 | +22:02:37.3 | HIP 42293 | 8.08 |
| 2026-05-16 12:00 | 08:37:15.55 | +22:01:23.8 | HIP 42293 | 2.90 |
| 2026-05-17 00:00 | 08:37:40.75 | +22:00:09.7 | HIP 42293 | 4.74 |
| 2026-05-17 12:00 | 08:38:06.07 | +21:58:54.8 | HIP 42293 | 10.41 |
| 2026-05-18 00:00 | 08:38:31.48 | +21:57:39.3 | HIP 42293 | 16.34 |
| 2026-05-18 12:00 | 08:38:57.01 | +21:56:23.1 | HIP 42293 | 22.35 |
| 2026-05-19 00:00 | 08:39:22.64 | +21:55:06.2 | HIP 42293 | 28.40 |
| 2026-05-19 12:00 | 08:39:48.37 | +21:53:48.7 | HIP 42293 | 34.49 |
| 2026-05-20 00:00 | 08:40:14.20 | +21:52:30.5 | HIP 42743 | 36.72 |
| 2026-05-20 12:00 | 08:40:40.13 | +21:51:11.7 | HIP 42743 | 31.86 |
| 2026-05-21 00:00 | 08:41:06.16 | +21:49:52.2 | HIP 42743 | 27.52 |
| 2026-05-21 12:00 | 08:41:32.29 | +21:48:32.1 | HIP 42743 | 23.98 |
| 2026-05-22 00:00 | 08:41:58.51 | +21:47:11.3 | HIP 42743 | 21.67 |
| 2026-05-22 12:00 | 08:42:24.82 | +21:45:49.9 | HIP 42743 | 21.03 |
| 2026-05-23 00:00 | 08:42:51.23 | +21:44:27.9 | HIP 42806 | 17.43 |
| 2026-05-23 12:00 | 08:43:17.72 | +21:43:05.2 | HIP 42806 | 14.97 |
| 2026-05-24 00:00 | 08:43:44.31 | +21:41:42.0 | HIP 42806 | 14.97 |
| 2026-05-24 12:00 | 08:44:10.98 | +21:40:18.1 | HIP 42927 | 15.05 |
| 2026-05-25 00:00 | 08:44:37.74 | +21:38:53.6 | HIP 42965 | 11.67 |
| 2026-05-25 12:00 | 08:45:04.59 | +21:37:28.4 | HIP 42965 | 5.71 |
| 2026-05-26 00:00 | 08:45:31.52 | +21:36:02.7 | HIP 42965 | 3.28 |
| 2026-05-26 12:00 | 08:45:58.53 | +21:34:36.4 | HIP 42965 | 8.47 |
| 2026-05-27 00:00 | 08:46:25.62 | +21:33:09.5 | HIP 42965 | 14.71 |
| 2026-05-27 12:00 | 08:46:52.79 | +21:31:42.0 | HIP 43188 | 15.29 |
| 2026-05-28 00:00 | 08:47:20.05 | +21:30:13.9 | HIP 43188 | 8.86 |
| 2026-05-28 12:00 | 08:47:47.38 | +21:28:45.2 | HIP 43188 | 2.78 |
| 2026-05-29 00:00 | 08:48:14.78 | +21:27:16.0 | HIP 43188 | 4.73 |
| 2026-05-29 12:00 | 08:48:42.27 | +21:25:46.1 | HIP 43259 | 7.73 |
| 2026-05-30 00:00 | 08:49:09.82 | +21:24:15.7 | HIP 43259 | 11.05 |
| 2026-05-30 12:00 | 08:49:37.45 | +21:22:44.7 | HIP 43259 | 16.49 |
| 2026-05-31 00:00 | 08:50:05.15 | +21:21:13.2 | HIP 43259 | 22.58 |
| 2026-05-31 12:00 | 08:50:32.93 | +21:19:41.1 | HIP 43479 | 18.84 |
| 2026-06-01 00:00 | 08:51:00.77 | +21:18:08.4 | HIP 43479 | 14.25 |
| 2026-06-01 12:00 | 08:51:28.68 | +21:16:35.2 | HIP 43479 | 11.85 |
| 2026-06-02 00:00 | 08:51:56.67 | +21:15:01.4 | HIP 43479 | 12.92 |