| 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) |
| 2026-05-12 00:00 |
17:30:13.09 |
+02:49:43.8 |
HIP 85601 |
15.01 |
| 2026-05-12 12:00 |
17:30:11.76 |
+02:49:49.9 |
HIP 85601 |
14.71 |
| 2026-05-13 00:00 |
17:30:10.43 |
+02:49:55.9 |
HIP 85601 |
14.41 |
| 2026-05-13 12:00 |
17:30:09.10 |
+02:50:01.8 |
HIP 85601 |
14.11 |
| 2026-05-14 00:00 |
17:30:07.76 |
+02:50:07.6 |
HIP 85601 |
13.81 |
| 2026-05-14 12:00 |
17:30:06.41 |
+02:50:13.4 |
HIP 85601 |
13.52 |
| 2026-05-15 00:00 |
17:30:05.05 |
+02:50:19.1 |
HIP 85601 |
13.22 |
| 2026-05-15 12:00 |
17:30:03.69 |
+02:50:24.8 |
HIP 85601 |
12.94 |
| 2026-05-16 00:00 |
17:30:02.32 |
+02:50:30.3 |
HIP 85601 |
12.65 |
| 2026-05-16 12:00 |
17:30:00.94 |
+02:50:35.8 |
HIP 85601 |
12.37 |
| 2026-05-17 00:00 |
17:29:59.56 |
+02:50:41.3 |
HIP 85601 |
12.09 |
| 2026-05-17 12:00 |
17:29:58.17 |
+02:50:46.6 |
HIP 85601 |
11.81 |
| 2026-05-18 00:00 |
17:29:56.78 |
+02:50:51.9 |
HIP 85601 |
11.54 |
| 2026-05-18 12:00 |
17:29:55.38 |
+02:50:57.1 |
HIP 85601 |
11.28 |
| 2026-05-19 00:00 |
17:29:53.97 |
+02:51:02.2 |
HIP 85601 |
11.02 |
| 2026-05-19 12:00 |
17:29:52.56 |
+02:51:07.3 |
HIP 85601 |
10.77 |
| 2026-05-20 00:00 |
17:29:51.14 |
+02:51:12.3 |
HIP 85601 |
10.52 |
| 2026-05-20 12:00 |
17:29:49.72 |
+02:51:17.2 |
HIP 85601 |
10.28 |
| 2026-05-21 00:00 |
17:29:48.29 |
+02:51:22.0 |
HIP 85601 |
10.05 |
| 2026-05-21 12:00 |
17:29:46.86 |
+02:51:26.8 |
HIP 85601 |
9.83 |
| 2026-05-22 00:00 |
17:29:45.42 |
+02:51:31.5 |
HIP 85601 |
9.62 |
| 2026-05-22 12:00 |
17:29:43.98 |
+02:51:36.1 |
HIP 85601 |
9.42 |
| 2026-05-23 00:00 |
17:29:42.53 |
+02:51:40.6 |
HIP 85601 |
9.23 |
| 2026-05-23 12:00 |
17:29:41.08 |
+02:51:45.1 |
HIP 85601 |
9.05 |
| 2026-05-24 00:00 |
17:29:39.62 |
+02:51:49.5 |
HIP 85601 |
8.88 |
| 2026-05-24 12:00 |
17:29:38.16 |
+02:51:53.8 |
HIP 85601 |
8.73 |
| 2026-05-25 00:00 |
17:29:36.70 |
+02:51:58.0 |
HIP 85601 |
8.60 |
| 2026-05-25 12:00 |
17:29:35.23 |
+02:52:02.2 |
HIP 85601 |
8.47 |
| 2026-05-26 00:00 |
17:29:33.75 |
+02:52:06.2 |
HIP 85601 |
8.37 |
| 2026-05-26 12:00 |
17:29:32.27 |
+02:52:10.2 |
HIP 85601 |
8.28 |
| 2026-05-27 00:00 |
17:29:30.79 |
+02:52:14.1 |
HIP 85601 |
8.21 |
| 2026-05-27 12:00 |
17:29:29.31 |
+02:52:18.0 |
HIP 85601 |
8.15 |
| 2026-05-28 00:00 |
17:29:27.82 |
+02:52:21.7 |
HIP 85601 |
8.12 |
| 2026-05-28 12:00 |
17:29:26.32 |
+02:52:25.4 |
HIP 85601 |
8.10 |
| 2026-05-29 00:00 |
17:29:24.82 |
+02:52:29.0 |
HIP 85601 |
8.10 |
| 2026-05-29 12:00 |
17:29:23.32 |
+02:52:32.5 |
HIP 85601 |
8.13 |
| 2026-05-30 00:00 |
17:29:21.82 |
+02:52:36.0 |
HIP 85601 |
8.17 |
| 2026-05-30 12:00 |
17:29:20.31 |
+02:52:39.3 |
HIP 85601 |
8.23 |
| 2026-05-31 00:00 |
17:29:18.80 |
+02:52:42.6 |
HIP 85601 |
8.31 |
| 2026-05-31 12:00 |
17:29:17.29 |
+02:52:45.8 |
HIP 85601 |
8.40 |
| 2026-06-01 00:00 |
17:29:15.77 |
+02:52:48.9 |
HIP 85601 |
8.52 |
| 2026-06-01 12:00 |
17:29:14.25 |
+02:52:52.0 |
HIP 85601 |
8.65 |
| 2026-06-02 00:00 |
17:29:12.73 |
+02:52:54.9 |
HIP 85601 |
8.80 |