| Parameter |
Value |
| Designation |
2P/Encke |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2023-10-22T03:35:18.398400Z |
| Orbit solution date (soln_date, UTC) |
2025-12-15T09:34:26Z |
| Obs used |
640 |
| NEO |
Yes |
| M1 |
15.600 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-09-25.0000000 |
| e |
0.84774970 |
| q (au) |
0.337948 |
| a (au) |
2.219689 |
| i (deg) |
11.412278 |
| Ω (om, deg) |
334.193585 |
| ω (w, deg) |
187.134246 |
| M (ma, deg) |
243.126069 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.799 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.799 |
| n |
2.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
00:32:14.92 |
+07:46:01.5 |
HIP 2609 |
17.13 |
| 2026-05-12 12:00 |
00:32:43.68 |
+07:49:43.8 |
HIP 2609 |
15.82 |
| 2026-05-13 00:00 |
00:33:12.40 |
+07:53:26.0 |
HIP 2609 |
18.32 |
| 2026-05-13 12:00 |
00:33:41.09 |
+07:57:08.2 |
HIP 2594 |
22.84 |
| 2026-05-14 00:00 |
00:34:09.75 |
+08:00:50.4 |
HIP 2751 |
22.57 |
| 2026-05-14 12:00 |
00:34:38.37 |
+08:04:32.6 |
HIP 2751 |
22.35 |
| 2026-05-15 00:00 |
00:35:06.96 |
+08:08:14.7 |
HIP 2751 |
24.85 |
| 2026-05-15 12:00 |
00:35:35.52 |
+08:11:56.9 |
HIP 2751 |
29.38 |
| 2026-05-16 00:00 |
00:36:04.04 |
+08:15:39.0 |
HIP 2751 |
35.15 |
| 2026-05-16 12:00 |
00:36:32.52 |
+08:19:21.0 |
HIP 3017 |
32.43 |
| 2026-05-17 00:00 |
00:37:00.97 |
+08:23:03.0 |
HIP 3017 |
24.50 |
| 2026-05-17 12:00 |
00:37:29.38 |
+08:26:45.0 |
HIP 3017 |
16.60 |
| 2026-05-18 00:00 |
00:37:57.75 |
+08:30:27.0 |
HIP 3017 |
8.79 |
| 2026-05-18 12:00 |
00:38:26.08 |
+08:34:08.8 |
HIP 3017 |
2.18 |
| 2026-05-19 00:00 |
00:38:54.37 |
+08:37:50.7 |
HIP 3017 |
7.58 |
| 2026-05-19 12:00 |
00:39:22.62 |
+08:41:32.4 |
HIP 3017 |
15.33 |
| 2026-05-20 00:00 |
00:39:50.83 |
+08:45:14.2 |
HIP 3017 |
23.17 |
| 2026-05-20 12:00 |
00:40:19.00 |
+08:48:55.8 |
HIP 3017 |
31.03 |
| 2026-05-21 00:00 |
00:40:47.12 |
+08:52:37.4 |
HIP 3236 |
29.34 |
| 2026-05-21 12:00 |
00:41:15.21 |
+08:56:18.9 |
HIP 3236 |
25.02 |
| 2026-05-22 00:00 |
00:41:43.24 |
+09:00:00.4 |
HIP 3384 |
19.32 |
| 2026-05-22 12:00 |
00:42:11.23 |
+09:03:41.8 |
HIP 3384 |
12.64 |
| 2026-05-23 00:00 |
00:42:39.18 |
+09:07:23.1 |
HIP 3384 |
8.31 |
| 2026-05-23 12:00 |
00:43:07.08 |
+09:11:04.3 |
HIP 3384 |
10.04 |
| 2026-05-24 00:00 |
00:43:34.94 |
+09:14:45.5 |
HIP 3384 |
15.95 |
| 2026-05-24 12:00 |
00:44:02.75 |
+09:18:26.6 |
HIP 3384 |
23.01 |
| 2026-05-25 00:00 |
00:44:30.51 |
+09:22:07.6 |
HIP 3384 |
30.41 |
| 2026-05-25 12:00 |
00:44:58.22 |
+09:25:48.5 |
HIP 3384 |
37.96 |
| 2026-05-26 00:00 |
00:45:25.89 |
+09:29:29.3 |
HIP 3701 |
42.31 |
| 2026-05-26 12:00 |
00:45:53.50 |
+09:33:10.1 |
HIP 3701 |
34.92 |
| 2026-05-27 00:00 |
00:46:21.07 |
+09:36:50.8 |
HIP 3701 |
27.74 |
| 2026-05-27 12:00 |
00:46:48.58 |
+09:40:31.4 |
HIP 3701 |
20.95 |
| 2026-05-28 00:00 |
00:47:16.05 |
+09:44:11.9 |
HIP 3701 |
15.08 |
| 2026-05-28 12:00 |
00:47:43.46 |
+09:47:52.3 |
HIP 3701 |
11.60 |
| 2026-05-29 00:00 |
00:48:10.82 |
+09:51:32.6 |
HIP 3799 |
9.23 |
| 2026-05-29 12:00 |
00:48:38.13 |
+09:55:12.9 |
HIP 3799 |
5.22 |
| 2026-05-30 00:00 |
00:49:05.38 |
+09:58:53.0 |
HIP 3799 |
9.31 |
| 2026-05-30 12:00 |
00:49:32.58 |
+10:02:33.0 |
HIP 3799 |
16.21 |
| 2026-05-31 00:00 |
00:49:59.72 |
+10:06:13.0 |
HIP 3960 |
20.13 |
| 2026-05-31 12:00 |
00:50:26.81 |
+10:09:52.8 |
HIP 3960 |
13.39 |
| 2026-06-01 00:00 |
00:50:53.84 |
+10:13:32.6 |
HIP 3960 |
8.33 |
| 2026-06-01 12:00 |
00:51:20.82 |
+10:17:12.2 |
HIP 3960 |
8.63 |
| 2026-06-02 00:00 |
00:51:47.74 |
+10:20:51.8 |
HIP 3960 |
13.92 |