218P/LINEAR
| Parameter |
Value |
| Designation |
218P/LINEAR |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2015-04-23T05:31:04.025280Z |
| Orbit solution date (soln_date, UTC) |
2026-01-07T20:37:06Z |
| Obs used |
481 |
| NEO |
Yes |
| M1 |
16.200 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-08-01.0000000 |
| e |
0.62174189 |
| q (au) |
1.171193 |
| a (au) |
3.096280 |
| i (deg) |
2.725205 |
| Ω (om, deg) |
176.026188 |
| ω (w, deg) |
59.665530 |
| M (ma, deg) |
84.258819 |
Magnitude
Scatter + Global Linear
$$
M_a = (18.233 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
18.233 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.785 |
| k |
0.800 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
16:46:19.02 |
-21:02:01.7 |
HIP 82244 |
27.02 |
| 2026-02-03 12:00 |
16:48:40.32 |
-21:05:06.3 |
HIP 82244 |
10.49 |
| 2026-02-04 00:00 |
16:51:01.79 |
-21:08:03.4 |
HIP 82519 |
17.34 |
| 2026-02-04 12:00 |
16:53:23.42 |
-21:10:53.0 |
HIP 82519 |
22.16 |
| 2026-02-05 00:00 |
16:55:45.20 |
-21:13:35.2 |
HIP 82822 |
20.79 |
| 2026-02-05 12:00 |
16:58:07.12 |
-21:16:09.8 |
HIP 83070 |
29.44 |
| 2026-02-06 00:00 |
17:00:29.17 |
-21:18:36.8 |
HIP 83224 |
9.08 |
| 2026-02-06 12:00 |
17:02:51.33 |
-21:20:56.2 |
HIP 83482 |
12.47 |
| 2026-02-07 00:00 |
17:05:13.59 |
-21:23:08.0 |
HIP 83679 |
13.88 |
| 2026-02-07 12:00 |
17:07:35.94 |
-21:25:12.0 |
HIP 83679 |
20.87 |
| 2026-02-08 00:00 |
17:09:58.37 |
-21:27:08.4 |
HIP 83969 |
20.47 |
| 2026-02-08 12:00 |
17:12:20.87 |
-21:28:57.1 |
HIP 84198 |
8.59 |
| 2026-02-09 00:00 |
17:14:43.42 |
-21:30:38.0 |
HIP 84198 |
29.38 |
| 2026-02-09 12:00 |
17:17:06.02 |
-21:32:11.1 |
HIP 84491 |
21.61 |
| 2026-02-10 00:00 |
17:19:28.64 |
-21:33:36.5 |
HIP 84798 |
7.15 |
| 2026-02-10 12:00 |
17:21:51.28 |
-21:34:54.0 |
HIP 84798 |
26.41 |
| 2026-02-11 00:00 |
17:24:13.92 |
-21:36:03.8 |
HIP 85121 |
6.42 |
| 2026-02-11 12:00 |
17:26:36.56 |
-21:37:05.7 |
HIP 85376 |
9.04 |
| 2026-02-12 00:00 |
17:28:59.18 |
-21:37:59.9 |
HIP 85724 |
30.23 |
| 2026-02-12 12:00 |
17:31:21.76 |
-21:38:46.2 |
HIP 85724 |
10.55 |
| 2026-02-13 00:00 |
17:33:44.30 |
-21:39:24.7 |
HIP 85908 |
21.85 |
| 2026-02-13 12:00 |
17:36:06.78 |
-21:39:55.5 |
HIP 86060 |
25.32 |
| 2026-02-14 00:00 |
17:38:29.19 |
-21:40:18.4 |
HIP 86352 |
14.90 |
| 2026-02-14 12:00 |
17:40:51.52 |
-21:40:33.5 |
HIP 86352 |
32.65 |
| 2026-02-15 00:00 |
17:43:13.76 |
-21:40:40.9 |
HIP 86736 |
2.83 |
| 2026-02-15 12:00 |
17:45:35.88 |
-21:40:40.5 |
HIP 86998 |
18.01 |
| 2026-02-16 00:00 |
17:47:57.89 |
-21:40:32.4 |
HIP 86998 |
20.55 |
| 2026-02-16 12:00 |
17:50:19.76 |
-21:40:16.5 |
HIP 87332 |
16.22 |
| 2026-02-17 00:00 |
17:52:41.50 |
-21:39:53.0 |
HIP 87578 |
12.77 |
| 2026-02-17 12:00 |
17:55:03.07 |
-21:39:21.9 |
HIP 87578 |
22.76 |
| 2026-02-18 00:00 |
17:57:24.48 |
-21:38:43.1 |
HIP 87925 |
5.86 |
| 2026-02-18 12:00 |
17:59:45.71 |
-21:37:56.7 |
HIP 87925 |
29.45 |
| 2026-02-19 00:00 |
18:02:06.75 |
-21:37:02.7 |
HIP 88325 |
21.04 |
| 2026-02-19 12:00 |
18:04:27.59 |
-21:36:01.2 |
HIP 88595 |
13.54 |
| 2026-02-20 00:00 |
18:06:48.21 |
-21:34:52.3 |
HIP 88730 |
4.60 |
| 2026-02-20 12:00 |
18:09:08.61 |
-21:33:35.9 |
HIP 88876 |
9.63 |
| 2026-02-21 00:00 |
18:11:28.77 |
-21:32:12.1 |
HIP 89029 |
21.44 |
| 2026-02-21 12:00 |
18:13:48.69 |
-21:30:41.0 |
HIP 89369 |
13.66 |
| 2026-02-22 00:00 |
18:16:08.35 |
-21:29:02.6 |
HIP 89369 |
29.53 |
| 2026-02-22 12:00 |
18:18:27.74 |
-21:27:17.0 |
HIP 89744 |
5.92 |
| 2026-02-23 00:00 |
18:20:46.85 |
-21:25:24.2 |
HIP 89744 |
26.56 |
| 2026-02-23 12:00 |
18:23:05.68 |
-21:23:24.2 |
HIP 90145 |
11.36 |
| 2026-02-24 00:00 |
18:25:24.21 |
-21:21:17.2 |
HIP 90145 |
22.88 |