| 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) |
| 2026-09-20 00:00 |
21:52:44.06 |
-42:36:54.9 |
HIP 107990 |
13.81 |
| 2026-09-20 12:00 |
21:52:42.58 |
-42:36:54.7 |
HIP 107990 |
13.81 |
| 2026-09-21 00:00 |
21:52:41.11 |
-42:36:54.4 |
HIP 107990 |
13.81 |
| 2026-09-21 12:00 |
21:52:39.65 |
-42:36:54.0 |
HIP 107990 |
13.82 |
| 2026-09-22 00:00 |
21:52:38.19 |
-42:36:53.5 |
HIP 107990 |
13.84 |
| 2026-09-22 12:00 |
21:52:36.75 |
-42:36:52.9 |
HIP 107990 |
13.86 |
| 2026-09-23 00:00 |
21:52:35.31 |
-42:36:52.1 |
HIP 107990 |
13.89 |
| 2026-09-23 12:00 |
21:52:33.89 |
-42:36:51.3 |
HIP 107990 |
13.93 |
| 2026-09-24 00:00 |
21:52:32.47 |
-42:36:50.4 |
HIP 107990 |
13.97 |
| 2026-09-24 12:00 |
21:52:31.06 |
-42:36:49.4 |
HIP 107990 |
14.02 |
| 2026-09-25 00:00 |
21:52:29.66 |
-42:36:48.3 |
HIP 107990 |
14.08 |
| 2026-09-25 12:00 |
21:52:28.26 |
-42:36:47.0 |
HIP 107990 |
14.14 |
| 2026-09-26 00:00 |
21:52:26.88 |
-42:36:45.7 |
HIP 107990 |
14.21 |
| 2026-09-26 12:00 |
21:52:25.51 |
-42:36:44.3 |
HIP 107990 |
14.28 |
| 2026-09-27 00:00 |
21:52:24.14 |
-42:36:42.7 |
HIP 107990 |
14.36 |
| 2026-09-27 12:00 |
21:52:22.79 |
-42:36:41.1 |
HIP 107990 |
14.44 |
| 2026-09-28 00:00 |
21:52:21.45 |
-42:36:39.4 |
HIP 107990 |
14.53 |
| 2026-09-28 12:00 |
21:52:20.11 |
-42:36:37.5 |
HIP 107990 |
14.62 |
| 2026-09-29 00:00 |
21:52:18.79 |
-42:36:35.6 |
HIP 107990 |
14.72 |
| 2026-09-29 12:00 |
21:52:17.47 |
-42:36:33.5 |
HIP 107990 |
14.82 |
| 2026-09-30 00:00 |
21:52:16.17 |
-42:36:31.4 |
HIP 107990 |
14.93 |
| 2026-09-30 12:00 |
21:52:14.87 |
-42:36:29.1 |
HIP 107990 |
15.04 |
| 2026-10-01 00:00 |
21:52:13.59 |
-42:36:26.8 |
HIP 107990 |
15.16 |
| 2026-10-01 12:00 |
21:52:12.31 |
-42:36:24.3 |
HIP 107990 |
15.27 |
| 2026-10-02 00:00 |
21:52:11.05 |
-42:36:21.8 |
HIP 107990 |
15.40 |
| 2026-10-02 12:00 |
21:52:09.79 |
-42:36:19.1 |
HIP 107990 |
15.52 |
| 2026-10-03 00:00 |
21:52:08.55 |
-42:36:16.4 |
HIP 107990 |
15.65 |
| 2026-10-03 12:00 |
21:52:07.32 |
-42:36:13.5 |
HIP 107990 |
15.78 |
| 2026-10-04 00:00 |
21:52:06.10 |
-42:36:10.5 |
HIP 107990 |
15.92 |
| 2026-10-04 12:00 |
21:52:04.89 |
-42:36:07.5 |
HIP 107990 |
16.06 |
| 2026-10-05 00:00 |
21:52:03.69 |
-42:36:04.3 |
HIP 107990 |
16.20 |
| 2026-10-05 12:00 |
21:52:02.50 |
-42:36:01.1 |
HIP 107990 |
16.34 |
| 2026-10-06 00:00 |
21:52:01.32 |
-42:35:57.7 |
HIP 107990 |
16.49 |
| 2026-10-06 12:00 |
21:52:00.16 |
-42:35:54.3 |
HIP 107990 |
16.63 |
| 2026-10-07 00:00 |
21:51:59.00 |
-42:35:50.7 |
HIP 107990 |
16.78 |
| 2026-10-07 12:00 |
21:51:57.86 |
-42:35:47.0 |
HIP 107990 |
16.94 |
| 2026-10-08 00:00 |
21:51:56.73 |
-42:35:43.3 |
HIP 107990 |
17.09 |
| 2026-10-08 12:00 |
21:51:55.61 |
-42:35:39.4 |
HIP 107990 |
17.25 |
| 2026-10-09 00:00 |
21:51:54.50 |
-42:35:35.5 |
HIP 107990 |
17.40 |
| 2026-10-09 12:00 |
21:51:53.41 |
-42:35:31.4 |
HIP 107990 |
17.56 |
| 2026-10-10 00:00 |
21:51:52.32 |
-42:35:27.3 |
HIP 107990 |
17.72 |
| 2026-10-10 12:00 |
21:51:51.25 |
-42:35:23.0 |
HIP 107990 |
17.88 |
| 2026-10-11 00:00 |
21:51:50.19 |
-42:35:18.7 |
HIP 107990 |
18.05 |