| Parameter |
Value |
| Designation |
2P/Encke |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2023-10-22T12:38:24.702720Z |
| Orbit solution date (soln_date, UTC) |
2026-10-01T15:11:48Z |
| Obs used |
880 |
| NEO |
Yes |
| M1 |
15.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-07-22.0000000 |
| e |
0.84695324 |
| q (au) |
0.339591 |
| a (au) |
2.218871 |
| i (deg) |
11.337097 |
| Ω (om, deg) |
334.024066 |
| ω (w, deg) |
187.282041 |
| M (ma, deg) |
332.408652 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.171 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.171 |
| n |
2.000 |
| gf |
0.996 |
| gb |
-0.802 |
| k |
0.952 |
| δ90 |
9.998 |
| 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) |
| 2026-09-25 00:00 |
01:02:03.27 |
+20:23:39.8 |
HIP 4715 |
21.98 |
| 2026-09-25 12:00 |
01:01:10.32 |
+20:22:41.1 |
HIP 4715 |
10.10 |
| 2026-09-26 00:00 |
01:00:16.60 |
+20:21:37.1 |
HIP 4715 |
5.62 |
| 2026-09-26 12:00 |
00:59:22.12 |
+20:20:27.7 |
HIP 4596 |
14.20 |
| 2026-09-27 00:00 |
00:58:26.88 |
+20:19:13.0 |
HIP 4596 |
14.54 |
| 2026-09-27 12:00 |
00:57:30.87 |
+20:17:52.7 |
HIP 4596 |
23.85 |
| 2026-09-28 00:00 |
00:56:34.11 |
+20:16:26.9 |
HIP 4316 |
18.71 |
| 2026-09-28 12:00 |
00:55:36.61 |
+20:14:55.4 |
HIP 4316 |
6.05 |
| 2026-09-29 00:00 |
00:54:38.35 |
+20:13:18.3 |
HIP 4316 |
9.77 |
| 2026-09-29 12:00 |
00:53:39.36 |
+20:11:35.3 |
HIP 4243 |
9.77 |
| 2026-09-30 00:00 |
00:52:39.63 |
+20:09:46.5 |
HIP 4243 |
21.62 |
| 2026-09-30 12:00 |
00:51:39.17 |
+20:07:51.7 |
HIP 4061 |
27.56 |
| 2026-10-01 00:00 |
00:50:37.99 |
+20:05:51.0 |
HIP 3855 |
19.13 |
| 2026-10-01 12:00 |
00:49:36.09 |
+20:03:44.2 |
HIP 3855 |
4.48 |
| 2026-10-02 00:00 |
00:48:33.50 |
+20:01:31.2 |
HIP 3855 |
10.47 |
| 2026-10-02 12:00 |
00:47:30.20 |
+19:59:12.0 |
HIP 3636 |
18.38 |
| 2026-10-03 00:00 |
00:46:26.21 |
+19:56:46.6 |
HIP 3636 |
16.20 |
| 2026-10-03 12:00 |
00:45:21.55 |
+19:54:14.9 |
HIP 3636 |
25.68 |
| 2026-10-04 00:00 |
00:44:16.22 |
+19:51:36.8 |
HIP 3502 |
35.82 |
| 2026-10-04 12:00 |
00:43:10.23 |
+19:48:52.3 |
HIP 3272 |
28.38 |
| 2026-10-05 00:00 |
00:42:03.60 |
+19:46:01.3 |
HIP 3272 |
22.79 |
| 2026-10-05 12:00 |
00:40:56.33 |
+19:43:03.8 |
HIP 3244 |
19.61 |
| 2026-10-06 00:00 |
00:39:48.44 |
+19:39:59.8 |
HIP 3014 |
20.66 |
| 2026-10-06 12:00 |
00:38:39.95 |
+19:36:49.1 |
HIP 3014 |
7.04 |
| 2026-10-07 00:00 |
00:37:30.87 |
+19:33:31.9 |
HIP 3014 |
14.75 |
| 2026-10-07 12:00 |
00:36:21.21 |
+19:30:08.0 |
HIP 3014 |
30.77 |
| 2026-10-08 00:00 |
00:35:10.99 |
+19:26:37.5 |
HIP 2730 |
32.88 |
| 2026-10-08 12:00 |
00:34:00.22 |
+19:23:00.2 |
HIP 2730 |
31.60 |
| 2026-10-09 00:00 |
00:32:48.92 |
+19:19:16.3 |
HIP 2502 |
18.21 |
| 2026-10-09 12:00 |
00:31:37.11 |
+19:15:25.7 |
HIP 2502 |
13.58 |
| 2026-10-10 00:00 |
00:30:24.81 |
+19:11:28.4 |
HIP 2412 |
8.77 |
| 2026-10-10 12:00 |
00:29:12.03 |
+19:07:24.4 |
HIP 2316 |
7.24 |
| 2026-10-11 00:00 |
00:27:58.79 |
+19:03:13.7 |
HIP 2316 |
22.20 |
| 2026-10-11 12:00 |
00:26:45.11 |
+18:58:56.3 |
HIP 2048 |
12.56 |
| 2026-10-12 00:00 |
00:25:31.02 |
+18:54:32.2 |
HIP 2048 |
11.81 |
| 2026-10-12 12:00 |
00:24:16.53 |
+18:50:01.5 |
HIP 1888 |
16.34 |
| 2026-10-13 00:00 |
00:23:01.66 |
+18:45:24.2 |
HIP 1888 |
15.95 |
| 2026-10-13 12:00 |
00:21:46.43 |
+18:40:40.4 |
HIP 1664 |
17.78 |
| 2026-10-14 00:00 |
00:20:30.86 |
+18:35:49.9 |
HIP 1664 |
8.28 |
| 2026-10-14 12:00 |
00:19:14.98 |
+18:30:53.0 |
HIP 1664 |
22.64 |
| 2026-10-15 00:00 |
00:17:58.80 |
+18:25:49.7 |
HIP 1373 |
18.83 |
| 2026-10-15 12:00 |
00:16:42.35 |
+18:20:39.9 |
HIP 1373 |
12.13 |
| 2026-10-16 00:00 |
00:15:25.66 |
+18:15:23.8 |
HIP 1373 |
25.57 |