| Parameter |
Value |
| Designation |
C/1981 H1 (Bus) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1981-07-30T18:36:24.347520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:29Z |
| Obs used |
26 |
| NEO |
- |
| M1 |
10.700 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1981-06-01.0000000 |
| e |
0.99886154 |
| q (au) |
2.458094 |
| a (au) |
2159.137236 |
| i (deg) |
160.663680 |
| Ω (om, deg) |
24.264517 |
| ω (w, deg) |
189.851632 |
| M (ma, deg) |
359.999413 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.833 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.833 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.864 |
| 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) |
| 2026-06-01 00:00 |
02:19:53.30 |
+09:53:23.3 |
HIP 10937 |
16.24 |
| 2026-06-01 12:00 |
02:19:54.60 |
+09:53:29.3 |
HIP 10937 |
15.90 |
| 2026-06-02 00:00 |
02:19:55.90 |
+09:53:35.2 |
HIP 10937 |
15.57 |
| 2026-06-02 12:00 |
02:19:57.19 |
+09:53:41.0 |
HIP 10937 |
15.25 |
| 2026-06-03 00:00 |
02:19:58.48 |
+09:53:46.8 |
HIP 10937 |
14.92 |
| 2026-06-03 12:00 |
02:19:59.75 |
+09:53:52.6 |
HIP 10937 |
14.59 |
| 2026-06-04 00:00 |
02:20:01.02 |
+09:53:58.3 |
HIP 10937 |
14.27 |
| 2026-06-04 12:00 |
02:20:02.28 |
+09:54:03.9 |
HIP 10937 |
13.95 |
| 2026-06-05 00:00 |
02:20:03.54 |
+09:54:09.5 |
HIP 10937 |
13.64 |
| 2026-06-05 12:00 |
02:20:04.78 |
+09:54:15.0 |
HIP 10937 |
13.32 |
| 2026-06-06 00:00 |
02:20:06.02 |
+09:54:20.5 |
HIP 10937 |
13.01 |
| 2026-06-06 12:00 |
02:20:07.25 |
+09:54:26.0 |
HIP 10937 |
12.70 |
| 2026-06-07 00:00 |
02:20:08.47 |
+09:54:31.3 |
HIP 10937 |
12.39 |
| 2026-06-07 12:00 |
02:20:09.68 |
+09:54:36.7 |
HIP 10937 |
12.09 |
| 2026-06-08 00:00 |
02:20:10.89 |
+09:54:41.9 |
HIP 10937 |
11.79 |
| 2026-06-08 12:00 |
02:20:12.08 |
+09:54:47.1 |
HIP 10937 |
11.49 |
| 2026-06-09 00:00 |
02:20:13.27 |
+09:54:52.3 |
HIP 10937 |
11.19 |
| 2026-06-09 12:00 |
02:20:14.45 |
+09:54:57.4 |
HIP 10937 |
10.90 |
| 2026-06-10 00:00 |
02:20:15.62 |
+09:55:02.4 |
HIP 10937 |
10.60 |
| 2026-06-10 12:00 |
02:20:16.78 |
+09:55:07.4 |
HIP 10937 |
10.32 |
| 2026-06-11 00:00 |
02:20:17.93 |
+09:55:12.4 |
HIP 10937 |
10.03 |
| 2026-06-11 12:00 |
02:20:19.07 |
+09:55:17.2 |
HIP 10937 |
9.75 |
| 2026-06-12 00:00 |
02:20:20.20 |
+09:55:22.0 |
HIP 10937 |
9.47 |
| 2026-06-12 12:00 |
02:20:21.33 |
+09:55:26.8 |
HIP 10937 |
9.19 |
| 2026-06-13 00:00 |
02:20:22.44 |
+09:55:31.5 |
HIP 10937 |
8.92 |
| 2026-06-13 12:00 |
02:20:23.55 |
+09:55:36.1 |
HIP 10937 |
8.65 |
| 2026-06-14 00:00 |
02:20:24.64 |
+09:55:40.7 |
HIP 10937 |
8.38 |
| 2026-06-14 12:00 |
02:20:25.73 |
+09:55:45.2 |
HIP 10937 |
8.12 |
| 2026-06-15 00:00 |
02:20:26.81 |
+09:55:49.7 |
HIP 10937 |
7.86 |
| 2026-06-15 12:00 |
02:20:27.87 |
+09:55:54.1 |
HIP 10937 |
7.61 |
| 2026-06-16 00:00 |
02:20:28.93 |
+09:55:58.4 |
HIP 10937 |
7.35 |
| 2026-06-16 12:00 |
02:20:29.98 |
+09:56:02.7 |
HIP 10937 |
7.11 |
| 2026-06-17 00:00 |
02:20:31.01 |
+09:56:06.9 |
HIP 10937 |
6.86 |
| 2026-06-17 12:00 |
02:20:32.04 |
+09:56:11.0 |
HIP 10937 |
6.62 |
| 2026-06-18 00:00 |
02:20:33.06 |
+09:56:15.1 |
HIP 10937 |
6.39 |
| 2026-06-18 12:00 |
02:20:34.06 |
+09:56:19.2 |
HIP 10937 |
6.16 |
| 2026-06-19 00:00 |
02:20:35.06 |
+09:56:23.1 |
HIP 10937 |
5.93 |
| 2026-06-19 12:00 |
02:20:36.04 |
+09:56:27.0 |
HIP 10937 |
5.71 |
| 2026-06-20 00:00 |
02:20:37.02 |
+09:56:30.9 |
HIP 10937 |
5.49 |
| 2026-06-20 12:00 |
02:20:37.98 |
+09:56:34.6 |
HIP 10937 |
5.28 |
| 2026-06-21 00:00 |
02:20:38.93 |
+09:56:38.3 |
HIP 10937 |
5.08 |
| 2026-06-21 12:00 |
02:20:39.88 |
+09:56:42.0 |
HIP 10937 |
4.88 |
| 2026-06-22 00:00 |
02:20:40.81 |
+09:56:45.6 |
HIP 10937 |
4.68 |