| 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) |
| 2026-03-26 00:00 |
02:16:33.82 |
+09:35:45.6 |
HIP 10614 |
10.24 |
| 2026-03-26 12:00 |
02:16:35.16 |
+09:35:53.8 |
HIP 10614 |
10.07 |
| 2026-03-27 00:00 |
02:16:36.51 |
+09:36:02.0 |
HIP 10614 |
9.90 |
| 2026-03-27 12:00 |
02:16:37.87 |
+09:36:10.2 |
HIP 10614 |
9.75 |
| 2026-03-28 00:00 |
02:16:39.23 |
+09:36:18.4 |
HIP 10614 |
9.61 |
| 2026-03-28 12:00 |
02:16:40.60 |
+09:36:26.6 |
HIP 10614 |
9.48 |
| 2026-03-29 00:00 |
02:16:41.97 |
+09:36:34.9 |
HIP 10614 |
9.36 |
| 2026-03-29 12:00 |
02:16:43.35 |
+09:36:43.1 |
HIP 10614 |
9.25 |
| 2026-03-30 00:00 |
02:16:44.74 |
+09:36:51.4 |
HIP 10614 |
9.16 |
| 2026-03-30 12:00 |
02:16:46.13 |
+09:36:59.8 |
HIP 10614 |
9.08 |
| 2026-03-31 00:00 |
02:16:47.53 |
+09:37:08.1 |
HIP 10614 |
9.02 |
| 2026-03-31 12:00 |
02:16:48.94 |
+09:37:16.4 |
HIP 10614 |
8.97 |
| 2026-04-01 00:00 |
02:16:50.35 |
+09:37:24.8 |
HIP 10614 |
8.94 |
| 2026-04-01 12:00 |
02:16:51.77 |
+09:37:33.2 |
HIP 10614 |
8.92 |
| 2026-04-02 00:00 |
02:16:53.19 |
+09:37:41.6 |
HIP 10614 |
8.92 |
| 2026-04-02 12:00 |
02:16:54.62 |
+09:37:50.0 |
HIP 10614 |
8.94 |
| 2026-04-03 00:00 |
02:16:56.05 |
+09:37:58.4 |
HIP 10614 |
8.97 |
| 2026-04-03 12:00 |
02:16:57.50 |
+09:38:06.8 |
HIP 10614 |
9.02 |
| 2026-04-04 00:00 |
02:16:58.94 |
+09:38:15.3 |
HIP 10634 |
9.01 |
| 2026-04-04 12:00 |
02:17:00.39 |
+09:38:23.7 |
HIP 10634 |
8.94 |
| 2026-04-05 00:00 |
02:17:01.85 |
+09:38:32.2 |
HIP 10634 |
8.89 |
| 2026-04-05 12:00 |
02:17:03.31 |
+09:38:40.7 |
HIP 10634 |
8.85 |
| 2026-04-06 00:00 |
02:17:04.78 |
+09:38:49.1 |
HIP 10634 |
8.84 |
| 2026-04-06 12:00 |
02:17:06.25 |
+09:38:57.6 |
HIP 10634 |
8.83 |
| 2026-04-07 00:00 |
02:17:07.72 |
+09:39:06.2 |
HIP 10634 |
8.85 |
| 2026-04-07 12:00 |
02:17:09.20 |
+09:39:14.7 |
HIP 10634 |
8.88 |
| 2026-04-08 00:00 |
02:17:10.69 |
+09:39:23.2 |
HIP 10634 |
8.93 |
| 2026-04-08 12:00 |
02:17:12.18 |
+09:39:31.7 |
HIP 10634 |
9.00 |
| 2026-04-09 00:00 |
02:17:13.67 |
+09:39:40.3 |
HIP 10634 |
9.09 |
| 2026-04-09 12:00 |
02:17:15.17 |
+09:39:48.8 |
HIP 10634 |
9.19 |
| 2026-04-10 00:00 |
02:17:16.67 |
+09:39:57.4 |
HIP 10634 |
9.31 |
| 2026-04-10 12:00 |
02:17:18.18 |
+09:40:05.9 |
HIP 10634 |
9.44 |
| 2026-04-11 00:00 |
02:17:19.69 |
+09:40:14.5 |
HIP 10634 |
9.59 |
| 2026-04-11 12:00 |
02:17:21.20 |
+09:40:23.1 |
HIP 10634 |
9.76 |
| 2026-04-12 00:00 |
02:17:22.72 |
+09:40:31.6 |
HIP 10634 |
9.93 |
| 2026-04-12 12:00 |
02:17:24.24 |
+09:40:40.2 |
HIP 10634 |
10.13 |
| 2026-04-13 00:00 |
02:17:25.76 |
+09:40:48.8 |
HIP 10634 |
10.33 |
| 2026-04-13 12:00 |
02:17:27.29 |
+09:40:57.3 |
HIP 10634 |
10.55 |
| 2026-04-14 00:00 |
02:17:28.82 |
+09:41:05.9 |
HIP 10634 |
10.77 |
| 2026-04-14 12:00 |
02:17:30.36 |
+09:41:14.5 |
HIP 10634 |
11.01 |
| 2026-04-15 00:00 |
02:17:31.89 |
+09:41:23.1 |
HIP 10634 |
11.26 |
| 2026-04-15 12:00 |
02:17:33.43 |
+09:41:31.6 |
HIP 10634 |
11.52 |
| 2026-04-16 00:00 |
02:17:34.98 |
+09:41:40.2 |
HIP 10634 |
11.78 |