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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 17:29:45.22 | -13:19:00.6 | HIP 85691 | 14.25 |
| 2026-09-20 12:00 | 17:29:45.33 | -13:19:04.5 | HIP 85691 | 14.22 |
| 2026-09-21 00:00 | 17:29:45.45 | -13:19:08.5 | HIP 85691 | 14.18 |
| 2026-09-21 12:00 | 17:29:45.58 | -13:19:12.5 | HIP 85691 | 14.14 |
| 2026-09-22 00:00 | 17:29:45.73 | -13:19:16.4 | HIP 85691 | 14.10 |
| 2026-09-22 12:00 | 17:29:45.89 | -13:19:20.4 | HIP 85691 | 14.05 |
| 2026-09-23 00:00 | 17:29:46.06 | -13:19:24.4 | HIP 85691 | 14.01 |
| 2026-09-23 12:00 | 17:29:46.25 | -13:19:28.4 | HIP 85691 | 13.95 |
| 2026-09-24 00:00 | 17:29:46.44 | -13:19:32.4 | HIP 85691 | 13.90 |
| 2026-09-24 12:00 | 17:29:46.65 | -13:19:36.4 | HIP 85691 | 13.84 |
| 2026-09-25 00:00 | 17:29:46.88 | -13:19:40.4 | HIP 85691 | 13.78 |
| 2026-09-25 12:00 | 17:29:47.11 | -13:19:44.4 | HIP 85691 | 13.72 |
| 2026-09-26 00:00 | 17:29:47.36 | -13:19:48.4 | HIP 85691 | 13.66 |
| 2026-09-26 12:00 | 17:29:47.62 | -13:19:52.4 | HIP 85691 | 13.59 |
| 2026-09-27 00:00 | 17:29:47.89 | -13:19:56.4 | HIP 85691 | 13.52 |
| 2026-09-27 12:00 | 17:29:48.18 | -13:20:00.5 | HIP 85691 | 13.44 |
| 2026-09-28 00:00 | 17:29:48.48 | -13:20:04.5 | HIP 85691 | 13.37 |
| 2026-09-28 12:00 | 17:29:48.79 | -13:20:08.5 | HIP 85691 | 13.29 |
| 2026-09-29 00:00 | 17:29:49.11 | -13:20:12.5 | HIP 85691 | 13.20 |
| 2026-09-29 12:00 | 17:29:49.45 | -13:20:16.6 | HIP 85691 | 13.12 |
| 2026-09-30 00:00 | 17:29:49.80 | -13:20:20.6 | HIP 85691 | 13.03 |
| 2026-09-30 12:00 | 17:29:50.16 | -13:20:24.6 | HIP 85691 | 12.94 |
| 2026-10-01 00:00 | 17:29:50.53 | -13:20:28.7 | HIP 85691 | 12.85 |
| 2026-10-01 12:00 | 17:29:50.92 | -13:20:32.7 | HIP 85691 | 12.75 |
| 2026-10-02 00:00 | 17:29:51.31 | -13:20:36.7 | HIP 85691 | 12.66 |
| 2026-10-02 12:00 | 17:29:51.72 | -13:20:40.8 | HIP 85691 | 12.56 |
| 2026-10-03 00:00 | 17:29:52.15 | -13:20:44.8 | HIP 85691 | 12.45 |
| 2026-10-03 12:00 | 17:29:52.58 | -13:20:48.8 | HIP 85691 | 12.35 |
| 2026-10-04 00:00 | 17:29:53.03 | -13:20:52.9 | HIP 85691 | 12.24 |
| 2026-10-04 12:00 | 17:29:53.49 | -13:20:56.9 | HIP 85691 | 12.12 |
| 2026-10-05 00:00 | 17:29:53.96 | -13:21:00.9 | HIP 85691 | 12.01 |
| 2026-10-05 12:00 | 17:29:54.45 | -13:21:05.0 | HIP 85691 | 11.89 |
| 2026-10-06 00:00 | 17:29:54.94 | -13:21:09.0 | HIP 85691 | 11.78 |
| 2026-10-06 12:00 | 17:29:55.45 | -13:21:13.0 | HIP 85691 | 11.65 |
| 2026-10-07 00:00 | 17:29:55.97 | -13:21:17.0 | HIP 85691 | 11.53 |
| 2026-10-07 12:00 | 17:29:56.51 | -13:21:21.0 | HIP 85691 | 11.40 |
| 2026-10-08 00:00 | 17:29:57.05 | -13:21:25.1 | HIP 85691 | 11.27 |
| 2026-10-08 12:00 | 17:29:57.61 | -13:21:29.1 | HIP 85691 | 11.14 |
| 2026-10-09 00:00 | 17:29:58.18 | -13:21:33.1 | HIP 85691 | 11.01 |
| 2026-10-09 12:00 | 17:29:58.76 | -13:21:37.1 | HIP 85691 | 10.87 |
| 2026-10-10 00:00 | 17:29:59.36 | -13:21:41.1 | HIP 85691 | 10.73 |
| 2026-10-10 12:00 | 17:29:59.96 | -13:21:45.1 | HIP 85691 | 10.59 |
| 2026-10-11 00:00 | 17:30:00.58 | -13:21:49.1 | HIP 85691 | 10.45 |