C/1963 A1 (Ikeya)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/1963 A1 (Ikeya) |
| Type | C |
| Perihelion (tp_cal, UTC) | 1963-03-21T11:23:55.291200Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:29:16Z |
| Obs used | 33 |
| NEO | - |
| M1 | - |
| K1 | - |
| PC | 0.030 |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 1963-04-26.0000000 |
| e | 0.99338425 |
| q (au) | 0.632140 |
| a (au) | 95.550699 |
| i (deg) | 160.648837 |
| Ω (om, deg) | 53.219499 |
| ω (w, deg) | 336.302578 |
| M (ma, deg) | 0.037488 |
Magnitude
Scatter + Global Linear
$$ M_a = (6.550 + 5.309\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 6.550 |
| n | 5.309 |
| gf | 0.800 |
| gb | -1.000 |
| k | 0.883 |
| δ90 | 5.499 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) | End (UTC) | a | b |
|---|---|---|---|
| 1963-01-14 | 1963-03-21 | +1.7201 | +0.327 |
| 1963-03-21 | 1963-10-12 | -1.6935 | +2.278 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-06-01 00:00 | 17:33:29.10 | -13:13:28.4 | HIP 85939 | 17.64 |
| 2026-06-01 12:00 | 17:33:27.61 | -13:13:26.5 | HIP 85939 | 17.78 |
| 2026-06-02 00:00 | 17:33:26.11 | -13:13:24.7 | HIP 85871 | 17.74 |
| 2026-06-02 12:00 | 17:33:24.61 | -13:13:23.0 | HIP 85871 | 17.59 |
| 2026-06-03 00:00 | 17:33:23.11 | -13:13:21.2 | HIP 85871 | 17.45 |
| 2026-06-03 12:00 | 17:33:21.60 | -13:13:19.5 | HIP 85871 | 17.31 |
| 2026-06-04 00:00 | 17:33:20.10 | -13:13:17.8 | HIP 85871 | 17.18 |
| 2026-06-04 12:00 | 17:33:18.59 | -13:13:16.2 | HIP 85871 | 17.06 |
| 2026-06-05 00:00 | 17:33:17.08 | -13:13:14.5 | HIP 85871 | 16.94 |
| 2026-06-05 12:00 | 17:33:15.56 | -13:13:12.9 | HIP 85871 | 16.83 |
| 2026-06-06 00:00 | 17:33:14.05 | -13:13:11.4 | HIP 85871 | 16.73 |
| 2026-06-06 12:00 | 17:33:12.53 | -13:13:09.9 | HIP 85871 | 16.63 |
| 2026-06-07 00:00 | 17:33:11.01 | -13:13:08.4 | HIP 85871 | 16.54 |
| 2026-06-07 12:00 | 17:33:09.49 | -13:13:06.9 | HIP 85871 | 16.45 |
| 2026-06-08 00:00 | 17:33:07.96 | -13:13:05.4 | HIP 85871 | 16.38 |
| 2026-06-08 12:00 | 17:33:06.44 | -13:13:04.0 | HIP 85871 | 16.31 |
| 2026-06-09 00:00 | 17:33:04.91 | -13:13:02.7 | HIP 85871 | 16.25 |
| 2026-06-09 12:00 | 17:33:03.38 | -13:13:01.3 | HIP 85871 | 16.20 |
| 2026-06-10 00:00 | 17:33:01.85 | -13:13:00.0 | HIP 85871 | 16.15 |
| 2026-06-10 12:00 | 17:33:00.32 | -13:12:58.7 | HIP 85871 | 16.12 |
| 2026-06-11 00:00 | 17:32:58.79 | -13:12:57.5 | HIP 85871 | 16.09 |
| 2026-06-11 12:00 | 17:32:57.26 | -13:12:56.2 | HIP 85871 | 16.07 |
| 2026-06-12 00:00 | 17:32:55.72 | -13:12:55.1 | HIP 85871 | 16.05 |
| 2026-06-12 12:00 | 17:32:54.19 | -13:12:53.9 | HIP 85871 | 16.05 |
| 2026-06-13 00:00 | 17:32:52.65 | -13:12:52.8 | HIP 85871 | 16.05 |
| 2026-06-13 12:00 | 17:32:51.12 | -13:12:51.7 | HIP 85871 | 16.06 |
| 2026-06-14 00:00 | 17:32:49.58 | -13:12:50.6 | HIP 85871 | 16.08 |
| 2026-06-14 12:00 | 17:32:48.05 | -13:12:49.6 | HIP 85871 | 16.11 |
| 2026-06-15 00:00 | 17:32:46.51 | -13:12:48.6 | HIP 85871 | 16.15 |
| 2026-06-15 12:00 | 17:32:44.97 | -13:12:47.6 | HIP 85871 | 16.19 |
| 2026-06-16 00:00 | 17:32:43.44 | -13:12:46.7 | HIP 85871 | 16.24 |
| 2026-06-16 12:00 | 17:32:41.90 | -13:12:45.8 | HIP 85871 | 16.30 |
| 2026-06-17 00:00 | 17:32:40.37 | -13:12:44.9 | HIP 85871 | 16.37 |
| 2026-06-17 12:00 | 17:32:38.83 | -13:12:44.1 | HIP 85871 | 16.44 |
| 2026-06-18 00:00 | 17:32:37.30 | -13:12:43.3 | HIP 85871 | 16.53 |
| 2026-06-18 12:00 | 17:32:35.76 | -13:12:42.5 | HIP 85871 | 16.62 |
| 2026-06-19 00:00 | 17:32:34.23 | -13:12:41.8 | HIP 85871 | 16.72 |
| 2026-06-19 12:00 | 17:32:32.70 | -13:12:41.1 | HIP 85871 | 16.82 |
| 2026-06-20 00:00 | 17:32:31.17 | -13:12:40.4 | HIP 85871 | 16.93 |
| 2026-06-20 12:00 | 17:32:29.64 | -13:12:39.8 | HIP 85871 | 17.05 |
| 2026-06-21 00:00 | 17:32:28.11 | -13:12:39.2 | HIP 85871 | 17.17 |
| 2026-06-21 12:00 | 17:32:26.58 | -13:12:38.6 | HIP 85871 | 17.31 |
| 2026-06-22 00:00 | 17:32:25.06 | -13:12:38.1 | HIP 85871 | 17.44 |