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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 17:34:25.19 | -13:15:04.0 | HIP 85939 | 17.34 |
| 2026-05-12 12:00 | 17:34:23.90 | -13:15:01.1 | HIP 85939 | 17.24 |
| 2026-05-13 00:00 | 17:34:22.61 | -13:14:58.2 | HIP 85939 | 17.14 |
| 2026-05-13 12:00 | 17:34:21.30 | -13:14:55.4 | HIP 85939 | 17.04 |
| 2026-05-14 00:00 | 17:34:20.00 | -13:14:52.6 | HIP 85939 | 16.95 |
| 2026-05-14 12:00 | 17:34:18.68 | -13:14:49.8 | HIP 85939 | 16.86 |
| 2026-05-15 00:00 | 17:34:17.36 | -13:14:47.0 | HIP 85939 | 16.77 |
| 2026-05-15 12:00 | 17:34:16.03 | -13:14:44.3 | HIP 85939 | 16.70 |
| 2026-05-16 00:00 | 17:34:14.69 | -13:14:41.6 | HIP 85939 | 16.62 |
| 2026-05-16 12:00 | 17:34:13.35 | -13:14:38.9 | HIP 85939 | 16.55 |
| 2026-05-17 00:00 | 17:34:12.00 | -13:14:36.2 | HIP 85939 | 16.49 |
| 2026-05-17 12:00 | 17:34:10.64 | -13:14:33.6 | HIP 85939 | 16.44 |
| 2026-05-18 00:00 | 17:34:09.28 | -13:14:30.9 | HIP 85939 | 16.38 |
| 2026-05-18 12:00 | 17:34:07.91 | -13:14:28.3 | HIP 85939 | 16.34 |
| 2026-05-19 00:00 | 17:34:06.54 | -13:14:25.8 | HIP 85939 | 16.30 |
| 2026-05-19 12:00 | 17:34:05.16 | -13:14:23.2 | HIP 85939 | 16.27 |
| 2026-05-20 00:00 | 17:34:03.77 | -13:14:20.7 | HIP 85939 | 16.24 |
| 2026-05-20 12:00 | 17:34:02.38 | -13:14:18.2 | HIP 85939 | 16.22 |
| 2026-05-21 00:00 | 17:34:00.99 | -13:14:15.7 | HIP 85939 | 16.21 |
| 2026-05-21 12:00 | 17:33:59.59 | -13:14:13.3 | HIP 85939 | 16.20 |
| 2026-05-22 00:00 | 17:33:58.18 | -13:14:10.9 | HIP 85939 | 16.20 |
| 2026-05-22 12:00 | 17:33:56.77 | -13:14:08.5 | HIP 85939 | 16.20 |
| 2026-05-23 00:00 | 17:33:55.35 | -13:14:06.1 | HIP 85939 | 16.22 |
| 2026-05-23 12:00 | 17:33:53.93 | -13:14:03.8 | HIP 85939 | 16.24 |
| 2026-05-24 00:00 | 17:33:52.50 | -13:14:01.5 | HIP 85939 | 16.26 |
| 2026-05-24 12:00 | 17:33:51.07 | -13:13:59.2 | HIP 85939 | 16.30 |
| 2026-05-25 00:00 | 17:33:49.63 | -13:13:57.0 | HIP 85939 | 16.34 |
| 2026-05-25 12:00 | 17:33:48.19 | -13:13:54.7 | HIP 85939 | 16.39 |
| 2026-05-26 00:00 | 17:33:46.75 | -13:13:52.5 | HIP 85939 | 16.44 |
| 2026-05-26 12:00 | 17:33:45.30 | -13:13:50.4 | HIP 85939 | 16.50 |
| 2026-05-27 00:00 | 17:33:43.84 | -13:13:48.2 | HIP 85939 | 16.57 |
| 2026-05-27 12:00 | 17:33:42.39 | -13:13:46.1 | HIP 85939 | 16.65 |
| 2026-05-28 00:00 | 17:33:40.92 | -13:13:44.0 | HIP 85939 | 16.73 |
| 2026-05-28 12:00 | 17:33:39.46 | -13:13:42.0 | HIP 85939 | 16.82 |
| 2026-05-29 00:00 | 17:33:37.99 | -13:13:39.9 | HIP 85939 | 16.92 |
| 2026-05-29 12:00 | 17:33:36.52 | -13:13:37.9 | HIP 85939 | 17.02 |
| 2026-05-30 00:00 | 17:33:35.04 | -13:13:36.0 | HIP 85939 | 17.13 |
| 2026-05-30 12:00 | 17:33:33.56 | -13:13:34.0 | HIP 85939 | 17.25 |
| 2026-05-31 00:00 | 17:33:32.08 | -13:13:32.1 | HIP 85939 | 17.37 |
| 2026-05-31 12:00 | 17:33:30.59 | -13:13:30.2 | HIP 85939 | 17.50 |
| 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 |