C/1973 E1 (Kohoutek)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/1973 E1 (Kohoutek) |
| Type | C |
| Perihelion (tp_cal, UTC) | 1973-12-28T10:20:11.054400Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:29:22Z |
| Obs used | 812 |
| NEO | - |
| M1 | 5.800 |
| K1 | 9.000 |
| PC | 0.030 |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 1973-12-06.0000000 |
| e | 1.00000781 |
| q (au) | 0.142425 |
| a (au) | -18236.507048 |
| i (deg) | 14.304145 |
| Ω (om, deg) | 258.489491 |
| ω (w, deg) | 37.797569 |
| M (ma, deg) | -0.000009 |
Magnitude
Scatter + Global Linear
$$ M_a = (6.623 + 3.235\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 6.623 |
| n | 3.235 |
| gf | 0.800 |
| gb | -0.633 |
| k | 0.800 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) | End (UTC) | a | b |
|---|---|---|---|
| 1973-01-28 | 1973-05-13 | +16.7992 | -9.089 |
| 1973-05-13 | 1973-10-27 | +2.0895 | -0.432 |
| 1973-10-27 | 1973-12-11 | +1.8010 | -0.605 |
| 1973-12-11 | 1973-12-22 | -4.2228 | -1.803 |
| 1974-01-03 | 1974-01-31 | -1.4588 | -0.127 |
| 1974-01-31 | 1974-02-24 | +4.7312 | +0.049 |
| 1974-02-24 | 1974-03-23 | +12.3726 | -1.280 |
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 | 07:22:37.70 | +14:22:22.8 | HIP 35772 | 5.41 |
| 2026-06-01 12:00 | 07:22:38.88 | +14:22:22.2 | HIP 35772 | 5.31 |
| 2026-06-02 00:00 | 07:22:40.06 | +14:22:21.6 | HIP 35772 | 5.23 |
| 2026-06-02 12:00 | 07:22:41.26 | +14:22:21.0 | HIP 35772 | 5.16 |
| 2026-06-03 00:00 | 07:22:42.46 | +14:22:20.3 | HIP 35772 | 5.11 |
| 2026-06-03 12:00 | 07:22:43.68 | +14:22:19.6 | HIP 35772 | 5.07 |
| 2026-06-04 00:00 | 07:22:44.89 | +14:22:18.8 | HIP 35772 | 5.05 |
| 2026-06-04 12:00 | 07:22:46.12 | +14:22:18.0 | HIP 35772 | 5.04 |
| 2026-06-05 00:00 | 07:22:47.35 | +14:22:17.2 | HIP 35772 | 5.06 |
| 2026-06-05 12:00 | 07:22:48.59 | +14:22:16.3 | HIP 35772 | 5.08 |
| 2026-06-06 00:00 | 07:22:49.84 | +14:22:15.5 | HIP 35772 | 5.13 |
| 2026-06-06 12:00 | 07:22:51.09 | +14:22:14.5 | HIP 35772 | 5.19 |
| 2026-06-07 00:00 | 07:22:52.35 | +14:22:13.6 | HIP 35772 | 5.27 |
| 2026-06-07 12:00 | 07:22:53.62 | +14:22:12.6 | HIP 35772 | 5.37 |
| 2026-06-08 00:00 | 07:22:54.90 | +14:22:11.5 | HIP 35772 | 5.48 |
| 2026-06-08 12:00 | 07:22:56.18 | +14:22:10.5 | HIP 35772 | 5.61 |
| 2026-06-09 00:00 | 07:22:57.47 | +14:22:09.3 | HIP 35772 | 5.75 |
| 2026-06-09 12:00 | 07:22:58.76 | +14:22:08.2 | HIP 35772 | 5.91 |
| 2026-06-10 00:00 | 07:23:00.06 | +14:22:07.0 | HIP 35772 | 6.08 |
| 2026-06-10 12:00 | 07:23:01.37 | +14:22:05.8 | HIP 35772 | 6.26 |
| 2026-06-11 00:00 | 07:23:02.68 | +14:22:04.6 | HIP 35772 | 6.45 |
| 2026-06-11 12:00 | 07:23:04.00 | +14:22:03.3 | HIP 35772 | 6.65 |
| 2026-06-12 00:00 | 07:23:05.33 | +14:22:02.0 | HIP 35772 | 6.86 |
| 2026-06-12 12:00 | 07:23:06.66 | +14:22:00.6 | HIP 35772 | 7.08 |
| 2026-06-13 00:00 | 07:23:07.99 | +14:21:59.2 | HIP 35772 | 7.31 |
| 2026-06-13 12:00 | 07:23:09.34 | +14:21:57.8 | HIP 35772 | 7.54 |
| 2026-06-14 00:00 | 07:23:10.69 | +14:21:56.3 | HIP 35772 | 7.79 |
| 2026-06-14 12:00 | 07:23:12.04 | +14:21:54.8 | HIP 35772 | 8.04 |
| 2026-06-15 00:00 | 07:23:13.40 | +14:21:53.3 | HIP 35772 | 8.30 |
| 2026-06-15 12:00 | 07:23:14.77 | +14:21:51.8 | HIP 35772 | 8.56 |
| 2026-06-16 00:00 | 07:23:16.14 | +14:21:50.2 | HIP 35772 | 8.83 |
| 2026-06-16 12:00 | 07:23:17.51 | +14:21:48.5 | HIP 35772 | 9.10 |
| 2026-06-17 00:00 | 07:23:18.89 | +14:21:46.9 | HIP 35772 | 9.38 |
| 2026-06-17 12:00 | 07:23:20.28 | +14:21:45.2 | HIP 35772 | 9.66 |
| 2026-06-18 00:00 | 07:23:21.67 | +14:21:43.4 | HIP 35772 | 9.95 |
| 2026-06-18 12:00 | 07:23:23.06 | +14:21:41.7 | HIP 35772 | 10.24 |
| 2026-06-19 00:00 | 07:23:24.46 | +14:21:39.9 | HIP 35772 | 10.53 |
| 2026-06-19 12:00 | 07:23:25.87 | +14:21:38.0 | HIP 35772 | 10.83 |
| 2026-06-20 00:00 | 07:23:27.28 | +14:21:36.2 | HIP 35772 | 11.13 |
| 2026-06-20 12:00 | 07:23:28.69 | +14:21:34.3 | HIP 35772 | 11.43 |
| 2026-06-21 00:00 | 07:23:30.11 | +14:21:32.3 | HIP 35772 | 11.74 |
| 2026-06-21 12:00 | 07:23:31.53 | +14:21:30.4 | HIP 35772 | 12.05 |
| 2026-06-22 00:00 | 07:23:32.95 | +14:21:28.4 | HIP 35772 | 12.36 |