C/1972 U1 (Kojima)
| Parameter |
Value |
| Designation |
C/1972 U1 (Kojima) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1973-02-12T06:40:27.632640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:22Z |
| Obs used |
267 |
| NEO |
- |
| M1 |
6.400 |
| K1 |
12.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1973-01-19.0000000 |
| e |
1.00104251 |
| q (au) |
2.147034 |
| a (au) |
-2059.482629 |
| i (deg) |
141.855558 |
| Ω (om, deg) |
43.188266 |
| ω (w, deg) |
334.305975 |
| M (ma, deg) |
-0.000256 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.867 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.867 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.559 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
17:31:00.15 |
+02:21:26.4 |
HIP 85798 |
14.68 |
| 2026-02-03 12:00 |
17:31:01.10 |
+02:21:33.2 |
HIP 85798 |
14.52 |
| 2026-02-04 00:00 |
17:31:02.04 |
+02:21:40.0 |
HIP 85798 |
14.36 |
| 2026-02-04 12:00 |
17:31:02.96 |
+02:21:46.9 |
HIP 85798 |
14.21 |
| 2026-02-05 00:00 |
17:31:03.88 |
+02:21:53.8 |
HIP 85798 |
14.06 |
| 2026-02-05 12:00 |
17:31:04.78 |
+02:22:00.9 |
HIP 85798 |
13.92 |
| 2026-02-06 00:00 |
17:31:05.68 |
+02:22:07.9 |
HIP 85798 |
13.78 |
| 2026-02-06 12:00 |
17:31:06.56 |
+02:22:15.1 |
HIP 85798 |
13.65 |
| 2026-02-07 00:00 |
17:31:07.43 |
+02:22:22.3 |
HIP 85798 |
13.53 |
| 2026-02-07 12:00 |
17:31:08.29 |
+02:22:29.5 |
HIP 85798 |
13.41 |
| 2026-02-08 00:00 |
17:31:09.15 |
+02:22:36.8 |
HIP 85798 |
13.30 |
| 2026-02-08 12:00 |
17:31:09.99 |
+02:22:44.2 |
HIP 85798 |
13.20 |
| 2026-02-09 00:00 |
17:31:10.82 |
+02:22:51.6 |
HIP 85798 |
13.10 |
| 2026-02-09 12:00 |
17:31:11.63 |
+02:22:59.1 |
HIP 85798 |
13.01 |
| 2026-02-10 00:00 |
17:31:12.44 |
+02:23:06.6 |
HIP 85798 |
12.93 |
| 2026-02-10 12:00 |
17:31:13.24 |
+02:23:14.2 |
HIP 85798 |
12.85 |
| 2026-02-11 00:00 |
17:31:14.02 |
+02:23:21.9 |
HIP 85798 |
12.78 |
| 2026-02-11 12:00 |
17:31:14.80 |
+02:23:29.6 |
HIP 85798 |
12.71 |
| 2026-02-12 00:00 |
17:31:15.56 |
+02:23:37.3 |
HIP 85798 |
12.65 |
| 2026-02-12 12:00 |
17:31:16.31 |
+02:23:45.2 |
HIP 85798 |
12.60 |
| 2026-02-13 00:00 |
17:31:17.05 |
+02:23:53.0 |
HIP 85798 |
12.56 |
| 2026-02-13 12:00 |
17:31:17.78 |
+02:24:00.9 |
HIP 85798 |
12.52 |
| 2026-02-14 00:00 |
17:31:18.49 |
+02:24:08.9 |
HIP 85798 |
12.49 |
| 2026-02-14 12:00 |
17:31:19.20 |
+02:24:16.9 |
HIP 85798 |
12.46 |
| 2026-02-15 00:00 |
17:31:19.89 |
+02:24:25.0 |
HIP 85798 |
12.45 |
| 2026-02-15 12:00 |
17:31:20.57 |
+02:24:33.1 |
HIP 85798 |
12.43 |
| 2026-02-16 00:00 |
17:31:21.24 |
+02:24:41.3 |
HIP 85798 |
12.43 |
| 2026-02-16 12:00 |
17:31:21.90 |
+02:24:49.5 |
HIP 85798 |
12.43 |
| 2026-02-17 00:00 |
17:31:22.54 |
+02:24:57.8 |
HIP 85798 |
12.44 |
| 2026-02-17 12:00 |
17:31:23.17 |
+02:25:06.1 |
HIP 85798 |
12.45 |
| 2026-02-18 00:00 |
17:31:23.79 |
+02:25:14.5 |
HIP 85798 |
12.47 |
| 2026-02-18 12:00 |
17:31:24.40 |
+02:25:22.9 |
HIP 85798 |
12.49 |
| 2026-02-19 00:00 |
17:31:25.00 |
+02:25:31.3 |
HIP 85798 |
12.52 |
| 2026-02-19 12:00 |
17:31:25.58 |
+02:25:39.8 |
HIP 85798 |
12.56 |
| 2026-02-20 00:00 |
17:31:26.15 |
+02:25:48.4 |
HIP 85798 |
12.60 |
| 2026-02-20 12:00 |
17:31:26.71 |
+02:25:57.0 |
HIP 85798 |
12.65 |
| 2026-02-21 00:00 |
17:31:27.26 |
+02:26:05.6 |
HIP 85798 |
12.70 |
| 2026-02-21 12:00 |
17:31:27.79 |
+02:26:14.3 |
HIP 85798 |
12.76 |
| 2026-02-22 00:00 |
17:31:28.32 |
+02:26:23.0 |
HIP 85798 |
12.82 |
| 2026-02-22 12:00 |
17:31:28.83 |
+02:26:31.7 |
HIP 85798 |
12.88 |
| 2026-02-23 00:00 |
17:31:29.32 |
+02:26:40.5 |
HIP 85798 |
12.96 |
| 2026-02-23 12:00 |
17:31:29.81 |
+02:26:49.3 |
HIP 85798 |
13.03 |
| 2026-02-24 00:00 |
17:31:30.28 |
+02:26:58.2 |
HIP 85798 |
13.11 |