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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 07:21:57.72 | +14:22:15.8 | HIP 35772 | 12.49 |
| 2026-05-12 12:00 | 07:21:58.52 | +14:22:16.7 | HIP 35772 | 12.32 |
| 2026-05-13 00:00 | 07:21:59.34 | +14:22:17.5 | HIP 35772 | 12.14 |
| 2026-05-13 12:00 | 07:22:00.17 | +14:22:18.3 | HIP 35772 | 11.97 |
| 2026-05-14 00:00 | 07:22:01.01 | +14:22:19.1 | HIP 35772 | 11.79 |
| 2026-05-14 12:00 | 07:22:01.86 | +14:22:19.9 | HIP 35772 | 11.61 |
| 2026-05-15 00:00 | 07:22:02.72 | +14:22:20.6 | HIP 35772 | 11.42 |
| 2026-05-15 12:00 | 07:22:03.59 | +14:22:21.2 | HIP 35772 | 11.24 |
| 2026-05-16 00:00 | 07:22:04.47 | +14:22:21.9 | HIP 35772 | 11.06 |
| 2026-05-16 12:00 | 07:22:05.36 | +14:22:22.5 | HIP 35772 | 10.87 |
| 2026-05-17 00:00 | 07:22:06.26 | +14:22:23.0 | HIP 35772 | 10.68 |
| 2026-05-17 12:00 | 07:22:07.18 | +14:22:23.6 | HIP 35772 | 10.49 |
| 2026-05-18 00:00 | 07:22:08.10 | +14:22:24.0 | HIP 35772 | 10.30 |
| 2026-05-18 12:00 | 07:22:09.03 | +14:22:24.5 | HIP 35772 | 10.11 |
| 2026-05-19 00:00 | 07:22:09.97 | +14:22:24.9 | HIP 35772 | 9.92 |
| 2026-05-19 12:00 | 07:22:10.92 | +14:22:25.3 | HIP 35772 | 9.73 |
| 2026-05-20 00:00 | 07:22:11.89 | +14:22:25.6 | HIP 35772 | 9.53 |
| 2026-05-20 12:00 | 07:22:12.86 | +14:22:25.9 | HIP 35772 | 9.34 |
| 2026-05-21 00:00 | 07:22:13.84 | +14:22:26.2 | HIP 35772 | 9.14 |
| 2026-05-21 12:00 | 07:22:14.83 | +14:22:26.4 | HIP 35772 | 8.95 |
| 2026-05-22 00:00 | 07:22:15.83 | +14:22:26.6 | HIP 35772 | 8.75 |
| 2026-05-22 12:00 | 07:22:16.84 | +14:22:26.8 | HIP 35772 | 8.56 |
| 2026-05-23 00:00 | 07:22:17.86 | +14:22:26.9 | HIP 35772 | 8.37 |
| 2026-05-23 12:00 | 07:22:18.89 | +14:22:27.0 | HIP 35772 | 8.17 |
| 2026-05-24 00:00 | 07:22:19.92 | +14:22:27.0 | HIP 35772 | 7.98 |
| 2026-05-24 12:00 | 07:22:20.97 | +14:22:27.0 | HIP 35772 | 7.79 |
| 2026-05-25 00:00 | 07:22:22.02 | +14:22:27.0 | HIP 35772 | 7.60 |
| 2026-05-25 12:00 | 07:22:23.09 | +14:22:26.9 | HIP 35772 | 7.41 |
| 2026-05-26 00:00 | 07:22:24.16 | +14:22:26.8 | HIP 35772 | 7.23 |
| 2026-05-26 12:00 | 07:22:25.24 | +14:22:26.7 | HIP 35772 | 7.05 |
| 2026-05-27 00:00 | 07:22:26.33 | +14:22:26.5 | HIP 35772 | 6.87 |
| 2026-05-27 12:00 | 07:22:27.43 | +14:22:26.3 | HIP 35772 | 6.69 |
| 2026-05-28 00:00 | 07:22:28.54 | +14:22:26.1 | HIP 35772 | 6.52 |
| 2026-05-28 12:00 | 07:22:29.66 | +14:22:25.8 | HIP 35772 | 6.36 |
| 2026-05-29 00:00 | 07:22:30.78 | +14:22:25.5 | HIP 35772 | 6.20 |
| 2026-05-29 12:00 | 07:22:31.91 | +14:22:25.1 | HIP 35772 | 6.05 |
| 2026-05-30 00:00 | 07:22:33.05 | +14:22:24.7 | HIP 35772 | 5.90 |
| 2026-05-30 12:00 | 07:22:34.20 | +14:22:24.3 | HIP 35772 | 5.76 |
| 2026-05-31 00:00 | 07:22:35.36 | +14:22:23.8 | HIP 35772 | 5.64 |
| 2026-05-31 12:00 | 07:22:36.52 | +14:22:23.3 | HIP 35772 | 5.52 |
| 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 |