C/1973 D1 (Kohoutek)
| Parameter |
Value |
| Designation |
C/1973 D1 (Kohoutek) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1973-06-07T04:20:15.918720Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:22Z |
| Obs used |
42 |
| NEO |
- |
| M1 |
9.700 |
| K1 |
18.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1973-04-20.0000000 |
| e |
0.99874973 |
| q (au) |
1.382021 |
| a (au) |
1105.378577 |
| i (deg) |
121.598063 |
| Ω (om, deg) |
164.817374 |
| ω (w, deg) |
74.859255 |
| M (ma, deg) |
359.998708 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.986 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.986 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
21:48:54.89 |
-63:33:11.6 |
HIP 107584 |
15.30 |
| 2026-02-03 12:00 |
21:48:58.09 |
-63:33:03.7 |
HIP 107584 |
15.63 |
| 2026-02-04 00:00 |
21:49:01.30 |
-63:32:55.9 |
HIP 107584 |
15.97 |
| 2026-02-04 12:00 |
21:49:04.51 |
-63:32:48.3 |
HIP 107584 |
16.31 |
| 2026-02-05 00:00 |
21:49:07.73 |
-63:32:40.7 |
HIP 107853 |
16.00 |
| 2026-02-05 12:00 |
21:49:10.95 |
-63:32:33.4 |
HIP 107853 |
15.64 |
| 2026-02-06 00:00 |
21:49:14.17 |
-63:32:26.1 |
HIP 107853 |
15.28 |
| 2026-02-06 12:00 |
21:49:17.40 |
-63:32:19.1 |
HIP 107853 |
14.92 |
| 2026-02-07 00:00 |
21:49:20.63 |
-63:32:12.1 |
HIP 107853 |
14.56 |
| 2026-02-07 12:00 |
21:49:23.87 |
-63:32:05.3 |
HIP 107853 |
14.21 |
| 2026-02-08 00:00 |
21:49:27.11 |
-63:31:58.7 |
HIP 107853 |
13.85 |
| 2026-02-08 12:00 |
21:49:30.35 |
-63:31:52.2 |
HIP 107853 |
13.50 |
| 2026-02-09 00:00 |
21:49:33.59 |
-63:31:45.8 |
HIP 107853 |
13.16 |
| 2026-02-09 12:00 |
21:49:36.84 |
-63:31:39.6 |
HIP 107853 |
12.81 |
| 2026-02-10 00:00 |
21:49:40.09 |
-63:31:33.5 |
HIP 107853 |
12.47 |
| 2026-02-10 12:00 |
21:49:43.34 |
-63:31:27.6 |
HIP 107853 |
12.14 |
| 2026-02-11 00:00 |
21:49:46.59 |
-63:31:21.9 |
HIP 107853 |
11.80 |
| 2026-02-11 12:00 |
21:49:49.84 |
-63:31:16.2 |
HIP 107853 |
11.48 |
| 2026-02-12 00:00 |
21:49:53.10 |
-63:31:10.8 |
HIP 107853 |
11.15 |
| 2026-02-12 12:00 |
21:49:56.35 |
-63:31:05.5 |
HIP 107853 |
10.83 |
| 2026-02-13 00:00 |
21:49:59.61 |
-63:31:00.3 |
HIP 107853 |
10.52 |
| 2026-02-13 12:00 |
21:50:02.87 |
-63:30:55.3 |
HIP 107853 |
10.21 |
| 2026-02-14 00:00 |
21:50:06.12 |
-63:30:50.4 |
HIP 107853 |
9.91 |
| 2026-02-14 12:00 |
21:50:09.38 |
-63:30:45.7 |
HIP 107853 |
9.62 |
| 2026-02-15 00:00 |
21:50:12.64 |
-63:30:41.2 |
HIP 107853 |
9.33 |
| 2026-02-15 12:00 |
21:50:15.89 |
-63:30:36.8 |
HIP 107853 |
9.05 |
| 2026-02-16 00:00 |
21:50:19.15 |
-63:30:32.5 |
HIP 107853 |
8.79 |
| 2026-02-16 12:00 |
21:50:22.41 |
-63:30:28.4 |
HIP 107853 |
8.53 |
| 2026-02-17 00:00 |
21:50:25.66 |
-63:30:24.5 |
HIP 107853 |
8.28 |
| 2026-02-17 12:00 |
21:50:28.91 |
-63:30:20.7 |
HIP 107853 |
8.04 |
| 2026-02-18 00:00 |
21:50:32.16 |
-63:30:17.0 |
HIP 107853 |
7.82 |
| 2026-02-18 12:00 |
21:50:35.41 |
-63:30:13.6 |
HIP 107853 |
7.61 |
| 2026-02-19 00:00 |
21:50:38.66 |
-63:30:10.2 |
HIP 107853 |
7.41 |
| 2026-02-19 12:00 |
21:50:41.90 |
-63:30:07.1 |
HIP 107853 |
7.23 |
| 2026-02-20 00:00 |
21:50:45.14 |
-63:30:04.0 |
HIP 107853 |
7.07 |
| 2026-02-20 12:00 |
21:50:48.38 |
-63:30:01.2 |
HIP 107853 |
6.92 |
| 2026-02-21 00:00 |
21:50:51.61 |
-63:29:58.5 |
HIP 107853 |
6.80 |
| 2026-02-21 12:00 |
21:50:54.85 |
-63:29:55.9 |
HIP 107853 |
6.69 |
| 2026-02-22 00:00 |
21:50:58.07 |
-63:29:53.6 |
HIP 107853 |
6.61 |
| 2026-02-22 12:00 |
21:51:01.30 |
-63:29:51.3 |
HIP 107853 |
6.54 |
| 2026-02-23 00:00 |
21:51:04.52 |
-63:29:49.2 |
HIP 107853 |
6.50 |
| 2026-02-23 12:00 |
21:51:07.73 |
-63:29:47.3 |
HIP 107853 |
6.48 |
| 2026-02-24 00:00 |
21:51:10.94 |
-63:29:45.6 |
HIP 107853 |
6.49 |