| 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) |
| 2026-03-26 00:00 |
17:31:34.70 |
+02:36:32.2 |
HIP 85749 |
7.69 |
| 2026-03-26 12:00 |
17:31:34.37 |
+02:36:42.0 |
HIP 85749 |
7.51 |
| 2026-03-27 00:00 |
17:31:34.03 |
+02:36:51.8 |
HIP 85749 |
7.33 |
| 2026-03-27 12:00 |
17:31:33.68 |
+02:37:01.6 |
HIP 85749 |
7.14 |
| 2026-03-28 00:00 |
17:31:33.31 |
+02:37:11.3 |
HIP 85749 |
6.95 |
| 2026-03-28 12:00 |
17:31:32.93 |
+02:37:21.1 |
HIP 85749 |
6.77 |
| 2026-03-29 00:00 |
17:31:32.53 |
+02:37:30.8 |
HIP 85749 |
6.58 |
| 2026-03-29 12:00 |
17:31:32.13 |
+02:37:40.6 |
HIP 85749 |
6.39 |
| 2026-03-30 00:00 |
17:31:31.71 |
+02:37:50.3 |
HIP 85749 |
6.20 |
| 2026-03-30 12:00 |
17:31:31.27 |
+02:38:00.0 |
HIP 85749 |
6.00 |
| 2026-03-31 00:00 |
17:31:30.83 |
+02:38:09.7 |
HIP 85749 |
5.81 |
| 2026-03-31 12:00 |
17:31:30.37 |
+02:38:19.4 |
HIP 85749 |
5.62 |
| 2026-04-01 00:00 |
17:31:29.90 |
+02:38:29.1 |
HIP 85749 |
5.42 |
| 2026-04-01 12:00 |
17:31:29.42 |
+02:38:38.7 |
HIP 85749 |
5.23 |
| 2026-04-02 00:00 |
17:31:28.92 |
+02:38:48.4 |
HIP 85749 |
5.03 |
| 2026-04-02 12:00 |
17:31:28.42 |
+02:38:58.0 |
HIP 85749 |
4.83 |
| 2026-04-03 00:00 |
17:31:27.89 |
+02:39:07.6 |
HIP 85749 |
4.64 |
| 2026-04-03 12:00 |
17:31:27.36 |
+02:39:17.2 |
HIP 85749 |
4.44 |
| 2026-04-04 00:00 |
17:31:26.82 |
+02:39:26.8 |
HIP 85749 |
4.25 |
| 2026-04-04 12:00 |
17:31:26.26 |
+02:39:36.3 |
HIP 85749 |
4.05 |
| 2026-04-05 00:00 |
17:31:25.69 |
+02:39:45.8 |
HIP 85749 |
3.86 |
| 2026-04-05 12:00 |
17:31:25.11 |
+02:39:55.3 |
HIP 85749 |
3.67 |
| 2026-04-06 00:00 |
17:31:24.51 |
+02:40:04.8 |
HIP 85749 |
3.48 |
| 2026-04-06 12:00 |
17:31:23.90 |
+02:40:14.3 |
HIP 85749 |
3.29 |
| 2026-04-07 00:00 |
17:31:23.28 |
+02:40:23.7 |
HIP 85749 |
3.11 |
| 2026-04-07 12:00 |
17:31:22.65 |
+02:40:33.1 |
HIP 85749 |
2.93 |
| 2026-04-08 00:00 |
17:31:22.01 |
+02:40:42.5 |
HIP 85749 |
2.76 |
| 2026-04-08 12:00 |
17:31:21.35 |
+02:40:51.8 |
HIP 85749 |
2.60 |
| 2026-04-09 00:00 |
17:31:20.69 |
+02:41:01.2 |
HIP 85749 |
2.45 |
| 2026-04-09 12:00 |
17:31:20.01 |
+02:41:10.5 |
HIP 85749 |
2.32 |
| 2026-04-10 00:00 |
17:31:19.31 |
+02:41:19.7 |
HIP 85749 |
2.20 |
| 2026-04-10 12:00 |
17:31:18.61 |
+02:41:29.0 |
HIP 85749 |
2.10 |
| 2026-04-11 00:00 |
17:31:17.89 |
+02:41:38.2 |
HIP 85749 |
2.02 |
| 2026-04-11 12:00 |
17:31:17.17 |
+02:41:47.4 |
HIP 85749 |
1.98 |
| 2026-04-12 00:00 |
17:31:16.43 |
+02:41:56.6 |
HIP 85749 |
1.96 |
| 2026-04-12 12:00 |
17:31:15.68 |
+02:42:05.7 |
HIP 85749 |
1.97 |
| 2026-04-13 00:00 |
17:31:14.91 |
+02:42:14.8 |
HIP 85749 |
2.02 |
| 2026-04-13 12:00 |
17:31:14.14 |
+02:42:23.8 |
HIP 85749 |
2.09 |
| 2026-04-14 00:00 |
17:31:13.35 |
+02:42:32.9 |
HIP 85749 |
2.20 |
| 2026-04-14 12:00 |
17:31:12.56 |
+02:42:41.8 |
HIP 85749 |
2.33 |
| 2026-04-15 00:00 |
17:31:11.75 |
+02:42:50.8 |
HIP 85749 |
2.48 |
| 2026-04-15 12:00 |
17:31:10.93 |
+02:42:59.7 |
HIP 85749 |
2.64 |
| 2026-04-16 00:00 |
17:31:10.10 |
+02:43:08.6 |
HIP 85749 |
2.83 |