| 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) |
| 2026-09-20 00:00 |
02:20:00.33 |
+09:49:14.4 |
HIP 10937 |
17.07 |
| 2026-09-20 12:00 |
02:19:58.98 |
+09:49:06.7 |
HIP 10937 |
17.41 |
| 2026-09-21 00:00 |
02:19:57.63 |
+09:48:58.9 |
HIP 10937 |
17.74 |
| 2026-09-21 12:00 |
02:19:56.26 |
+09:48:51.1 |
HIP 10937 |
18.09 |
| 2026-09-22 00:00 |
02:19:54.89 |
+09:48:43.3 |
HIP 10937 |
18.43 |
| 2026-09-22 12:00 |
02:19:53.50 |
+09:48:35.4 |
HIP 10937 |
18.78 |
| 2026-09-23 00:00 |
02:19:52.11 |
+09:48:27.5 |
HIP 10937 |
19.13 |
| 2026-09-23 12:00 |
02:19:50.71 |
+09:48:19.5 |
HIP 10937 |
19.48 |
| 2026-09-24 00:00 |
02:19:49.30 |
+09:48:11.5 |
HIP 10764 |
19.36 |
| 2026-09-24 12:00 |
02:19:47.89 |
+09:48:03.5 |
HIP 10764 |
19.03 |
| 2026-09-25 00:00 |
02:19:46.46 |
+09:47:55.5 |
HIP 10764 |
18.71 |
| 2026-09-25 12:00 |
02:19:45.02 |
+09:47:47.4 |
HIP 10764 |
18.38 |
| 2026-09-26 00:00 |
02:19:43.58 |
+09:47:39.3 |
HIP 10764 |
18.06 |
| 2026-09-26 12:00 |
02:19:42.13 |
+09:47:31.2 |
HIP 10764 |
17.73 |
| 2026-09-27 00:00 |
02:19:40.67 |
+09:47:23.0 |
HIP 10764 |
17.40 |
| 2026-09-27 12:00 |
02:19:39.20 |
+09:47:14.9 |
HIP 10764 |
17.08 |
| 2026-09-28 00:00 |
02:19:37.73 |
+09:47:06.6 |
HIP 10764 |
16.76 |
| 2026-09-28 12:00 |
02:19:36.24 |
+09:46:58.4 |
HIP 10764 |
16.43 |
| 2026-09-29 00:00 |
02:19:34.75 |
+09:46:50.1 |
HIP 10764 |
16.11 |
| 2026-09-29 12:00 |
02:19:33.25 |
+09:46:41.8 |
HIP 10764 |
15.79 |
| 2026-09-30 00:00 |
02:19:31.75 |
+09:46:33.5 |
HIP 10764 |
15.47 |
| 2026-09-30 12:00 |
02:19:30.24 |
+09:46:25.2 |
HIP 10764 |
15.16 |
| 2026-10-01 00:00 |
02:19:28.71 |
+09:46:16.8 |
HIP 10764 |
14.84 |
| 2026-10-01 12:00 |
02:19:27.19 |
+09:46:08.4 |
HIP 10764 |
14.53 |
| 2026-10-02 00:00 |
02:19:25.65 |
+09:46:00.0 |
HIP 10764 |
14.22 |
| 2026-10-02 12:00 |
02:19:24.11 |
+09:45:51.6 |
HIP 10764 |
13.92 |
| 2026-10-03 00:00 |
02:19:22.56 |
+09:45:43.1 |
HIP 10764 |
13.62 |
| 2026-10-03 12:00 |
02:19:21.00 |
+09:45:34.6 |
HIP 10764 |
13.32 |
| 2026-10-04 00:00 |
02:19:19.44 |
+09:45:26.1 |
HIP 10764 |
13.03 |
| 2026-10-04 12:00 |
02:19:17.87 |
+09:45:17.6 |
HIP 10764 |
12.74 |
| 2026-10-05 00:00 |
02:19:16.29 |
+09:45:09.1 |
HIP 10764 |
12.46 |
| 2026-10-05 12:00 |
02:19:14.71 |
+09:45:00.5 |
HIP 10764 |
12.19 |
| 2026-10-06 00:00 |
02:19:13.12 |
+09:44:51.9 |
HIP 10764 |
11.92 |
| 2026-10-06 12:00 |
02:19:11.53 |
+09:44:43.3 |
HIP 10764 |
11.66 |
| 2026-10-07 00:00 |
02:19:09.93 |
+09:44:34.7 |
HIP 10764 |
11.40 |
| 2026-10-07 12:00 |
02:19:08.32 |
+09:44:26.1 |
HIP 10764 |
11.16 |
| 2026-10-08 00:00 |
02:19:06.71 |
+09:44:17.5 |
HIP 10764 |
10.93 |
| 2026-10-08 12:00 |
02:19:05.09 |
+09:44:08.8 |
HIP 10764 |
10.71 |
| 2026-10-09 00:00 |
02:19:03.46 |
+09:44:00.1 |
HIP 10764 |
10.49 |
| 2026-10-09 12:00 |
02:19:01.83 |
+09:43:51.5 |
HIP 10764 |
10.30 |
| 2026-10-10 00:00 |
02:19:00.20 |
+09:43:42.8 |
HIP 10764 |
10.11 |
| 2026-10-10 12:00 |
02:18:58.56 |
+09:43:34.1 |
HIP 10764 |
9.94 |
| 2026-10-11 00:00 |
02:18:56.91 |
+09:43:25.3 |
HIP 10764 |
9.78 |