217P/LINEAR
Metadata
| Parameter | Value |
|---|---|
| Designation | 217P/LINEAR |
| Type | P |
| Perihelion (tp_cal, UTC) | 2009-09-08T16:04:53.149440Z |
| Orbit solution date (soln_date, UTC) | 2026-03-31T13:33:22Z |
| Obs used | 3339 |
| NEO | Yes |
| M1 | 14.500 |
| K1 | 4.750 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2012-12-22.0000000 |
| e | 0.68884715 |
| q (au) | 1.228911 |
| a (au) | 3.949540 |
| i (deg) | 12.861819 |
| Ω (om, deg) | 125.539247 |
| ω (w, deg) | 246.939807 |
| M (ma, deg) | 150.724894 |
Magnitude
Scatter + Global Linear
$$ M_a = (9.170 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 9.170 |
| n | 6.000 |
| gf | 0.987 |
| gb | -0.500 |
| k | 1.000 |
| δ90 | 9.996 |
| 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 | +4.3332 | -1.059 |
| 2025-11-02 | 2025-12-19 | +3.0862 | -0.542 |
| 2025-12-19 | 2026-02-14 | -38.2612 | +17.064 |
| 2026-02-14 | 2026-03-21 | +21.2517 | -12.231 |
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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 08:08:54.76 | +22:54:03.8 | HIP 39788 | 16.37 |
| 2026-03-26 12:00 | 08:08:59.26 | +22:54:26.2 | HIP 39788 | 17.46 |
| 2026-03-27 00:00 | 08:09:04.07 | +22:54:47.2 | HIP 39788 | 18.61 |
| 2026-03-27 12:00 | 08:09:09.19 | +22:55:06.9 | HIP 39788 | 19.82 |
| 2026-03-28 00:00 | 08:09:14.62 | +22:55:25.4 | HIP 39788 | 21.09 |
| 2026-03-28 12:00 | 08:09:20.35 | +22:55:42.5 | HIP 39788 | 22.42 |
| 2026-03-29 00:00 | 08:09:26.38 | +22:55:58.5 | HIP 39788 | 23.80 |
| 2026-03-29 12:00 | 08:09:32.71 | +22:56:13.1 | HIP 39788 | 25.24 |
| 2026-03-30 00:00 | 08:09:39.33 | +22:56:26.5 | HIP 39788 | 26.75 |
| 2026-03-30 12:00 | 08:09:46.25 | +22:56:38.7 | HIP 39788 | 28.31 |
| 2026-03-31 00:00 | 08:09:53.45 | +22:56:49.7 | HIP 39788 | 29.94 |
| 2026-03-31 12:00 | 08:10:00.95 | +22:56:59.5 | HIP 39788 | 31.62 |
| 2026-04-01 00:00 | 08:10:08.73 | +22:57:08.0 | HIP 39788 | 33.37 |
| 2026-04-01 12:00 | 08:10:16.79 | +22:57:15.4 | HIP 39788 | 35.18 |
| 2026-04-02 00:00 | 08:10:25.14 | +22:57:21.6 | HIP 40102 | 34.99 |
| 2026-04-02 12:00 | 08:10:33.76 | +22:57:26.6 | HIP 40102 | 34.10 |
| 2026-04-03 00:00 | 08:10:42.66 | +22:57:30.5 | HIP 40102 | 33.31 |
| 2026-04-03 12:00 | 08:10:51.84 | +22:57:33.2 | HIP 40102 | 32.63 |
| 2026-04-04 00:00 | 08:11:01.28 | +22:57:34.7 | HIP 40102 | 32.08 |
| 2026-04-04 12:00 | 08:11:11.00 | +22:57:35.1 | HIP 40102 | 31.68 |
| 2026-04-05 00:00 | 08:11:20.98 | +22:57:34.4 | HIP 40102 | 31.44 |
| 2026-04-05 12:00 | 08:11:31.23 | +22:57:32.6 | HIP 40102 | 31.39 |
| 2026-04-06 00:00 | 08:11:41.74 | +22:57:29.6 | HIP 40293 | 29.63 |
| 2026-04-06 12:00 | 08:11:52.51 | +22:57:25.6 | HIP 40293 | 27.36 |
| 2026-04-07 00:00 | 08:12:03.54 | +22:57:20.4 | HIP 40293 | 25.09 |
| 2026-04-07 12:00 | 08:12:14.83 | +22:57:14.1 | HIP 40293 | 22.83 |
| 2026-04-08 00:00 | 08:12:26.37 | +22:57:06.8 | HIP 40293 | 20.61 |
| 2026-04-08 12:00 | 08:12:38.16 | +22:56:58.4 | HIP 40293 | 18.47 |
| 2026-04-09 00:00 | 08:12:50.20 | +22:56:48.9 | HIP 40293 | 16.48 |
| 2026-04-09 12:00 | 08:13:02.49 | +22:56:38.3 | HIP 40293 | 14.72 |
| 2026-04-10 00:00 | 08:13:15.03 | +22:56:26.7 | HIP 40293 | 13.32 |
| 2026-04-10 12:00 | 08:13:27.81 | +22:56:14.1 | HIP 40293 | 12.45 |
| 2026-04-11 00:00 | 08:13:40.83 | +22:56:00.4 | HIP 40293 | 12.26 |
| 2026-04-11 12:00 | 08:13:54.09 | +22:55:45.6 | HIP 40293 | 12.83 |
| 2026-04-12 00:00 | 08:14:07.59 | +22:55:29.8 | HIP 40293 | 14.09 |
| 2026-04-12 12:00 | 08:14:21.32 | +22:55:13.0 | HIP 40293 | 15.92 |
| 2026-04-13 00:00 | 08:14:35.29 | +22:54:55.2 | HIP 40293 | 18.17 |
| 2026-04-13 12:00 | 08:14:49.49 | +22:54:36.4 | HIP 40293 | 20.73 |
| 2026-04-14 00:00 | 08:15:03.91 | +22:54:16.5 | HIP 40529 | 20.36 |
| 2026-04-14 12:00 | 08:15:18.57 | +22:53:55.7 | HIP 40529 | 17.06 |
| 2026-04-15 00:00 | 08:15:33.45 | +22:53:33.9 | HIP 40529 | 13.75 |
| 2026-04-15 12:00 | 08:15:48.55 | +22:53:11.0 | HIP 40529 | 10.48 |
| 2026-04-16 00:00 | 08:16:03.88 | +22:52:47.2 | HIP 40529 | 7.40 |