| Parameter |
Value |
| Designation |
C/1966 R1 (Ikeya-Everhart) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1966-08-05T07:42:01.379520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:17Z |
| Obs used |
23 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1966-09-23.0000000 |
| e |
1.00004638 |
| q (au) |
0.881833 |
| a (au) |
-19014.652685 |
| i (deg) |
48.278876 |
| Ω (om, deg) |
107.658924 |
| ω (w, deg) |
50.044476 |
| M (ma, deg) |
0.000018 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.490 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.490 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
0.982 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
21:55:41.24 |
-42:28:02.5 |
HIP 108021 |
33.50 |
| 2026-07-29 12:00 |
21:55:39.62 |
-42:28:11.9 |
HIP 108021 |
33.32 |
| 2026-07-30 00:00 |
21:55:38.00 |
-42:28:21.3 |
HIP 108021 |
33.14 |
| 2026-07-30 12:00 |
21:55:36.37 |
-42:28:30.6 |
HIP 108021 |
32.96 |
| 2026-07-31 00:00 |
21:55:34.73 |
-42:28:39.8 |
HIP 108021 |
32.78 |
| 2026-07-31 12:00 |
21:55:33.09 |
-42:28:49.0 |
HIP 108021 |
32.61 |
| 2026-08-01 00:00 |
21:55:31.44 |
-42:28:58.1 |
HIP 108021 |
32.43 |
| 2026-08-01 12:00 |
21:55:29.79 |
-42:29:07.1 |
HIP 108021 |
32.26 |
| 2026-08-02 00:00 |
21:55:28.14 |
-42:29:16.1 |
HIP 108021 |
32.08 |
| 2026-08-02 12:00 |
21:55:26.48 |
-42:29:25.0 |
HIP 108021 |
31.91 |
| 2026-08-03 00:00 |
21:55:24.81 |
-42:29:33.8 |
HIP 108021 |
31.74 |
| 2026-08-03 12:00 |
21:55:23.15 |
-42:29:42.5 |
HIP 108021 |
31.57 |
| 2026-08-04 00:00 |
21:55:21.47 |
-42:29:51.2 |
HIP 108021 |
31.40 |
| 2026-08-04 12:00 |
21:55:19.80 |
-42:29:59.8 |
HIP 108021 |
31.24 |
| 2026-08-05 00:00 |
21:55:18.11 |
-42:30:08.4 |
HIP 108021 |
31.07 |
| 2026-08-05 12:00 |
21:55:16.43 |
-42:30:16.8 |
HIP 108021 |
30.91 |
| 2026-08-06 00:00 |
21:55:14.74 |
-42:30:25.2 |
HIP 108021 |
30.75 |
| 2026-08-06 12:00 |
21:55:13.05 |
-42:30:33.5 |
HIP 108021 |
30.59 |
| 2026-08-07 00:00 |
21:55:11.35 |
-42:30:41.8 |
HIP 108021 |
30.43 |
| 2026-08-07 12:00 |
21:55:09.66 |
-42:30:50.0 |
HIP 108021 |
30.27 |
| 2026-08-08 00:00 |
21:55:07.95 |
-42:30:58.0 |
HIP 108021 |
30.12 |
| 2026-08-08 12:00 |
21:55:06.25 |
-42:31:06.1 |
HIP 108021 |
29.97 |
| 2026-08-09 00:00 |
21:55:04.54 |
-42:31:14.0 |
HIP 108021 |
29.81 |
| 2026-08-09 12:00 |
21:55:02.83 |
-42:31:21.9 |
HIP 108021 |
29.67 |
| 2026-08-10 00:00 |
21:55:01.11 |
-42:31:29.6 |
HIP 108021 |
29.52 |
| 2026-08-10 12:00 |
21:54:59.40 |
-42:31:37.3 |
HIP 108021 |
29.37 |
| 2026-08-11 00:00 |
21:54:57.68 |
-42:31:44.9 |
HIP 108021 |
29.23 |
| 2026-08-11 12:00 |
21:54:55.96 |
-42:31:52.5 |
HIP 108021 |
29.09 |
| 2026-08-12 00:00 |
21:54:54.23 |
-42:32:00.0 |
HIP 108021 |
28.95 |
| 2026-08-12 12:00 |
21:54:52.51 |
-42:32:07.3 |
HIP 108021 |
28.82 |
| 2026-08-13 00:00 |
21:54:50.78 |
-42:32:14.6 |
HIP 108021 |
28.68 |
| 2026-08-13 12:00 |
21:54:49.05 |
-42:32:21.8 |
HIP 108021 |
28.55 |
| 2026-08-14 00:00 |
21:54:47.32 |
-42:32:28.9 |
HIP 108021 |
28.42 |
| 2026-08-14 12:00 |
21:54:45.59 |
-42:32:36.0 |
HIP 108021 |
28.29 |
| 2026-08-15 00:00 |
21:54:43.86 |
-42:32:42.9 |
HIP 108021 |
28.17 |
| 2026-08-15 12:00 |
21:54:42.12 |
-42:32:49.8 |
HIP 108021 |
28.05 |
| 2026-08-16 00:00 |
21:54:40.39 |
-42:32:56.6 |
HIP 108021 |
27.93 |
| 2026-08-16 12:00 |
21:54:38.65 |
-42:33:03.3 |
HIP 108021 |
27.81 |
| 2026-08-17 00:00 |
21:54:36.91 |
-42:33:09.9 |
HIP 107990 |
27.55 |
| 2026-08-17 12:00 |
21:54:35.17 |
-42:33:16.4 |
HIP 107990 |
27.23 |
| 2026-08-18 00:00 |
21:54:33.44 |
-42:33:22.8 |
HIP 107990 |
26.92 |
| 2026-08-18 12:00 |
21:54:31.70 |
-42:33:29.2 |
HIP 107990 |
26.60 |
| 2026-08-19 00:00 |
21:54:29.96 |
-42:33:35.4 |
HIP 107990 |
26.29 |