217P/LINEAR
Metadata
| Parameter | Value |
|---|---|
| Designation | 217P/LINEAR |
| Type | P |
| Perihelion (tp_cal, UTC) | 2009-09-08T14:59:04.721280Z |
| Orbit solution date (soln_date, UTC) | 2026-07-07T05:52:40Z |
| Obs used | 3365 |
| NEO | Yes |
| M1 | 14.600 |
| K1 | 4.500 |
| PC | - |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2013-01-19.0000000 |
| e | 0.68879936 |
| q (au) | 1.229136 |
| a (au) | 3.949658 |
| i (deg) | 12.861360 |
| Ω (om, deg) | 125.535703 |
| ω (w, deg) | 246.944396 |
| M (ma, deg) | 154.239661 |
Magnitude
Scatter + Global Linear
$$ M_a = (10.106 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 10.106 |
| n | 6.000 |
| gf | 0.801 |
| gb | -0.500 |
| k | 0.874 |
| δ90 | 1.000 |
| 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 | -12.8918 | +1.338 |
| 2025-05-24 | 2025-11-02 | +5.5608 | -1.282 |
| 2025-11-02 | 2025-12-19 | +2.7111 | -0.241 |
| 2025-12-19 | 2026-02-15 | -32.1958 | +14.706 |
| 2026-02-15 | 2026-04-06 | +19.1139 | -10.797 |
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 | 10:40:26.51 | +13:35:55.1 | HIP 52249 | 2.50 |
| 2026-09-20 12:00 | 10:40:53.23 | +13:33:52.7 | HIP 52249 | 4.87 |
| 2026-09-21 00:00 | 10:41:19.88 | +13:31:50.8 | HIP 52249 | 11.55 |
| 2026-09-21 12:00 | 10:41:46.48 | +13:29:49.3 | HIP 52249 | 18.30 |
| 2026-09-22 00:00 | 10:42:13.01 | +13:27:48.1 | HIP 52249 | 25.04 |
| 2026-09-22 12:00 | 10:42:39.48 | +13:25:47.4 | HIP 52249 | 31.78 |
| 2026-09-23 00:00 | 10:43:05.88 | +13:23:47.1 | HIP 52519 | 29.76 |
| 2026-09-23 12:00 | 10:43:32.22 | +13:21:47.1 | HIP 52519 | 24.65 |
| 2026-09-24 00:00 | 10:43:58.49 | +13:19:47.6 | HIP 52519 | 20.50 |
| 2026-09-24 12:00 | 10:44:24.70 | +13:17:48.6 | HIP 52519 | 17.97 |
| 2026-09-25 00:00 | 10:44:50.84 | +13:15:49.9 | HIP 52519 | 17.74 |
| 2026-09-25 12:00 | 10:45:16.92 | +13:13:51.7 | HIP 52519 | 19.88 |
| 2026-09-26 00:00 | 10:45:42.92 | +13:11:54.0 | HIP 52744 | 21.35 |
| 2026-09-26 12:00 | 10:46:08.87 | +13:09:56.7 | HIP 52744 | 14.91 |
| 2026-09-27 00:00 | 10:46:34.74 | +13:07:59.8 | HIP 52746 | 8.69 |
| 2026-09-27 12:00 | 10:47:00.54 | +13:06:03.4 | HIP 52746 | 3.71 |
| 2026-09-28 00:00 | 10:47:26.28 | +13:04:07.4 | HIP 52746 | 6.19 |
| 2026-09-28 12:00 | 10:47:51.94 | +13:02:12.0 | HIP 52746 | 12.19 |
| 2026-09-29 00:00 | 10:48:17.54 | +13:00:17.0 | HIP 52915 | 18.01 |
| 2026-09-29 12:00 | 10:48:43.07 | +12:58:22.4 | HIP 52915 | 11.88 |
| 2026-09-30 00:00 | 10:49:08.52 | +12:56:28.4 | HIP 52915 | 6.51 |
| 2026-09-30 12:00 | 10:49:33.91 | +12:54:34.8 | HIP 52940 | 1.26 |
| 2026-10-01 00:00 | 10:49:59.22 | +12:52:41.7 | HIP 52942 | 6.19 |
| 2026-10-01 12:00 | 10:50:24.46 | +12:50:49.2 | HIP 52942 | 12.54 |
| 2026-10-02 00:00 | 10:50:49.63 | +12:48:57.1 | HIP 52942 | 18.93 |
| 2026-10-02 12:00 | 10:51:14.72 | +12:47:05.6 | HIP 52942 | 25.31 |
| 2026-10-03 00:00 | 10:51:39.74 | +12:45:14.6 | HIP 53234 | 25.05 |
| 2026-10-03 12:00 | 10:52:04.69 | +12:43:24.1 | HIP 53234 | 19.02 |
| 2026-10-04 00:00 | 10:52:29.56 | +12:41:34.1 | HIP 53234 | 13.30 |
| 2026-10-04 12:00 | 10:52:54.35 | +12:39:44.7 | HIP 53234 | 8.51 |
| 2026-10-05 00:00 | 10:53:19.07 | +12:37:55.8 | HIP 53234 | 6.90 |
| 2026-10-05 12:00 | 10:53:43.71 | +12:36:07.5 | HIP 53234 | 10.09 |
| 2026-10-06 00:00 | 10:54:08.27 | +12:34:19.7 | HIP 53315 | 12.27 |
| 2026-10-06 12:00 | 10:54:32.75 | +12:32:32.5 | HIP 53315 | 10.93 |
| 2026-10-07 00:00 | 10:54:57.15 | +12:30:45.9 | HIP 53315 | 12.88 |
| 2026-10-07 12:00 | 10:55:21.47 | +12:28:59.8 | HIP 53315 | 17.01 |
| 2026-10-08 00:00 | 10:55:45.72 | +12:27:14.4 | HIP 53315 | 22.10 |
| 2026-10-08 12:00 | 10:56:09.87 | +12:25:29.5 | HIP 53315 | 27.63 |
| 2026-10-09 00:00 | 10:56:33.95 | +12:23:45.3 | HIP 53315 | 33.35 |
| 2026-10-09 12:00 | 10:56:57.95 | +12:22:01.7 | HIP 53315 | 39.18 |
| 2026-10-10 00:00 | 10:57:21.85 | +12:20:18.6 | HIP 53716 | 40.37 |
| 2026-10-10 12:00 | 10:57:45.68 | +12:18:36.2 | HIP 53716 | 34.96 |
| 2026-10-11 00:00 | 10:58:09.42 | +12:16:54.5 | HIP 53716 | 29.82 |