| 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 |
1.000 |
| 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) |
| 2026-05-12 00:00 |
21:57:47.86 |
-41:58:59.3 |
HIP 108479 |
17.59 |
| 2026-05-12 12:00 |
21:57:48.09 |
-41:59:08.8 |
HIP 108479 |
17.71 |
| 2026-05-13 00:00 |
21:57:48.31 |
-41:59:18.4 |
HIP 108479 |
17.84 |
| 2026-05-13 12:00 |
21:57:48.51 |
-41:59:28.0 |
HIP 108479 |
17.97 |
| 2026-05-14 00:00 |
21:57:48.70 |
-41:59:37.7 |
HIP 108479 |
18.10 |
| 2026-05-14 12:00 |
21:57:48.87 |
-41:59:47.5 |
HIP 108479 |
18.23 |
| 2026-05-15 00:00 |
21:57:49.03 |
-41:59:57.3 |
HIP 108479 |
18.37 |
| 2026-05-15 12:00 |
21:57:49.17 |
-42:00:07.2 |
HIP 108479 |
18.51 |
| 2026-05-16 00:00 |
21:57:49.30 |
-42:00:17.1 |
HIP 108479 |
18.65 |
| 2026-05-16 12:00 |
21:57:49.41 |
-42:00:27.1 |
HIP 108479 |
18.79 |
| 2026-05-17 00:00 |
21:57:49.51 |
-42:00:37.1 |
HIP 108479 |
18.94 |
| 2026-05-17 12:00 |
21:57:49.59 |
-42:00:47.2 |
HIP 108479 |
19.08 |
| 2026-05-18 00:00 |
21:57:49.66 |
-42:00:57.4 |
HIP 108479 |
19.24 |
| 2026-05-18 12:00 |
21:57:49.71 |
-42:01:07.6 |
HIP 108479 |
19.39 |
| 2026-05-19 00:00 |
21:57:49.75 |
-42:01:17.9 |
HIP 108479 |
19.54 |
| 2026-05-19 12:00 |
21:57:49.78 |
-42:01:28.2 |
HIP 108479 |
19.70 |
| 2026-05-20 00:00 |
21:57:49.79 |
-42:01:38.6 |
HIP 108479 |
19.86 |
| 2026-05-20 12:00 |
21:57:49.78 |
-42:01:49.0 |
HIP 108479 |
20.02 |
| 2026-05-21 00:00 |
21:57:49.76 |
-42:01:59.5 |
HIP 108479 |
20.18 |
| 2026-05-21 12:00 |
21:57:49.73 |
-42:02:10.0 |
HIP 108479 |
20.35 |
| 2026-05-22 00:00 |
21:57:49.68 |
-42:02:20.6 |
HIP 108479 |
20.52 |
| 2026-05-22 12:00 |
21:57:49.61 |
-42:02:31.2 |
HIP 108479 |
20.69 |
| 2026-05-23 00:00 |
21:57:49.53 |
-42:02:41.9 |
HIP 108479 |
20.86 |
| 2026-05-23 12:00 |
21:57:49.44 |
-42:02:52.6 |
HIP 108479 |
21.03 |
| 2026-05-24 00:00 |
21:57:49.33 |
-42:03:03.3 |
HIP 108479 |
21.20 |
| 2026-05-24 12:00 |
21:57:49.20 |
-42:03:14.1 |
HIP 108479 |
21.38 |
| 2026-05-25 00:00 |
21:57:49.06 |
-42:03:25.0 |
HIP 108479 |
21.56 |
| 2026-05-25 12:00 |
21:57:48.91 |
-42:03:35.9 |
HIP 108479 |
21.74 |
| 2026-05-26 00:00 |
21:57:48.74 |
-42:03:46.8 |
HIP 108479 |
21.92 |
| 2026-05-26 12:00 |
21:57:48.56 |
-42:03:57.8 |
HIP 108479 |
22.10 |
| 2026-05-27 00:00 |
21:57:48.36 |
-42:04:08.8 |
HIP 108479 |
22.29 |
| 2026-05-27 12:00 |
21:57:48.15 |
-42:04:19.9 |
HIP 108479 |
22.47 |
| 2026-05-28 00:00 |
21:57:47.92 |
-42:04:31.0 |
HIP 108479 |
22.66 |
| 2026-05-28 12:00 |
21:57:47.68 |
-42:04:42.1 |
HIP 108479 |
22.85 |
| 2026-05-29 00:00 |
21:57:47.43 |
-42:04:53.3 |
HIP 108479 |
23.04 |
| 2026-05-29 12:00 |
21:57:47.16 |
-42:05:04.5 |
HIP 108479 |
23.24 |
| 2026-05-30 00:00 |
21:57:46.87 |
-42:05:15.8 |
HIP 108479 |
23.43 |
| 2026-05-30 12:00 |
21:57:46.57 |
-42:05:27.1 |
HIP 108479 |
23.63 |
| 2026-05-31 00:00 |
21:57:46.26 |
-42:05:38.4 |
HIP 108479 |
23.82 |
| 2026-05-31 12:00 |
21:57:45.93 |
-42:05:49.7 |
HIP 108479 |
24.02 |
| 2026-06-01 00:00 |
21:57:45.59 |
-42:06:01.1 |
HIP 108479 |
24.22 |
| 2026-06-01 12:00 |
21:57:45.23 |
-42:06:12.5 |
HIP 108479 |
24.42 |
| 2026-06-02 00:00 |
21:57:44.86 |
-42:06:24.0 |
HIP 108479 |
24.63 |