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) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 17:30:43.57 | -13:13:29.7 | HIP 85691 | 7.34 |
| 2026-07-29 12:00 | 17:30:42.45 | -13:13:31.6 | HIP 85691 | 7.31 |
| 2026-07-30 00:00 | 17:30:41.33 | -13:13:33.5 | HIP 85691 | 7.29 |
| 2026-07-30 12:00 | 17:30:40.23 | -13:13:35.5 | HIP 85691 | 7.28 |
| 2026-07-31 00:00 | 17:30:39.13 | -13:13:37.4 | HIP 85691 | 7.28 |
| 2026-07-31 12:00 | 17:30:38.04 | -13:13:39.4 | HIP 85691 | 7.29 |
| 2026-08-01 00:00 | 17:30:36.96 | -13:13:41.5 | HIP 85691 | 7.31 |
| 2026-08-01 12:00 | 17:30:35.89 | -13:13:43.5 | HIP 85691 | 7.33 |
| 2026-08-02 00:00 | 17:30:34.83 | -13:13:45.6 | HIP 85691 | 7.37 |
| 2026-08-02 12:00 | 17:30:33.78 | -13:13:47.8 | HIP 85691 | 7.41 |
| 2026-08-03 00:00 | 17:30:32.74 | -13:13:49.9 | HIP 85691 | 7.46 |
| 2026-08-03 12:00 | 17:30:31.70 | -13:13:52.1 | HIP 85691 | 7.52 |
| 2026-08-04 00:00 | 17:30:30.68 | -13:13:54.3 | HIP 85691 | 7.58 |
| 2026-08-04 12:00 | 17:30:29.67 | -13:13:56.5 | HIP 85691 | 7.65 |
| 2026-08-05 00:00 | 17:30:28.66 | -13:13:58.8 | HIP 85691 | 7.73 |
| 2026-08-05 12:00 | 17:30:27.67 | -13:14:01.1 | HIP 85691 | 7.81 |
| 2026-08-06 00:00 | 17:30:26.69 | -13:14:03.4 | HIP 85691 | 7.89 |
| 2026-08-06 12:00 | 17:30:25.71 | -13:14:05.7 | HIP 85691 | 7.98 |
| 2026-08-07 00:00 | 17:30:24.75 | -13:14:08.1 | HIP 85691 | 8.08 |
| 2026-08-07 12:00 | 17:30:23.79 | -13:14:10.5 | HIP 85691 | 8.18 |
| 2026-08-08 00:00 | 17:30:22.85 | -13:14:12.9 | HIP 85691 | 8.28 |
| 2026-08-08 12:00 | 17:30:21.92 | -13:14:15.4 | HIP 85691 | 8.39 |
| 2026-08-09 00:00 | 17:30:20.99 | -13:14:17.9 | HIP 85691 | 8.50 |
| 2026-08-09 12:00 | 17:30:20.08 | -13:14:20.4 | HIP 85691 | 8.61 |
| 2026-08-10 00:00 | 17:30:19.18 | -13:14:22.9 | HIP 85691 | 8.73 |
| 2026-08-10 12:00 | 17:30:18.29 | -13:14:25.5 | HIP 85691 | 8.84 |
| 2026-08-11 00:00 | 17:30:17.40 | -13:14:28.1 | HIP 85691 | 8.96 |
| 2026-08-11 12:00 | 17:30:16.53 | -13:14:30.7 | HIP 85691 | 9.08 |
| 2026-08-12 00:00 | 17:30:15.67 | -13:14:33.3 | HIP 85691 | 9.20 |
| 2026-08-12 12:00 | 17:30:14.82 | -13:14:36.0 | HIP 85691 | 9.32 |
| 2026-08-13 00:00 | 17:30:13.99 | -13:14:38.7 | HIP 85691 | 9.45 |
| 2026-08-13 12:00 | 17:30:13.16 | -13:14:41.4 | HIP 85691 | 9.57 |
| 2026-08-14 00:00 | 17:30:12.34 | -13:14:44.1 | HIP 85691 | 9.70 |
| 2026-08-14 12:00 | 17:30:11.54 | -13:14:46.9 | HIP 85691 | 9.82 |
| 2026-08-15 00:00 | 17:30:10.74 | -13:14:49.7 | HIP 85691 | 9.95 |
| 2026-08-15 12:00 | 17:30:09.96 | -13:14:52.5 | HIP 85691 | 10.07 |
| 2026-08-16 00:00 | 17:30:09.19 | -13:14:55.3 | HIP 85691 | 10.19 |
| 2026-08-16 12:00 | 17:30:08.43 | -13:14:58.2 | HIP 85691 | 10.32 |
| 2026-08-17 00:00 | 17:30:07.68 | -13:15:01.1 | HIP 85691 | 10.44 |
| 2026-08-17 12:00 | 17:30:06.94 | -13:15:04.0 | HIP 85691 | 10.57 |
| 2026-08-18 00:00 | 17:30:06.21 | -13:15:06.9 | HIP 85691 | 10.69 |
| 2026-08-18 12:00 | 17:30:05.50 | -13:15:09.9 | HIP 85691 | 10.81 |
| 2026-08-19 00:00 | 17:30:04.79 | -13:15:12.9 | HIP 85691 | 10.93 |