C/1981 H1 (Bus)
| 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) |
| 2026-02-03 00:00 |
02:15:11.12 |
+09:25:34.1 |
HIP 10414 |
22.52 |
| 2026-02-03 12:00 |
02:15:11.28 |
+09:25:37.1 |
HIP 10414 |
22.58 |
| 2026-02-04 00:00 |
02:15:11.46 |
+09:25:40.2 |
HIP 10414 |
22.65 |
| 2026-02-04 12:00 |
02:15:11.66 |
+09:25:43.4 |
HIP 10414 |
22.72 |
| 2026-02-05 00:00 |
02:15:11.87 |
+09:25:46.6 |
HIP 10414 |
22.79 |
| 2026-02-05 12:00 |
02:15:12.09 |
+09:25:49.9 |
HIP 10414 |
22.87 |
| 2026-02-06 00:00 |
02:15:12.33 |
+09:25:53.3 |
HIP 10414 |
22.95 |
| 2026-02-06 12:00 |
02:15:12.58 |
+09:25:56.8 |
HIP 10414 |
23.04 |
| 2026-02-07 00:00 |
02:15:12.84 |
+09:26:00.3 |
HIP 10414 |
23.13 |
| 2026-02-07 12:00 |
02:15:13.12 |
+09:26:03.9 |
HIP 10414 |
23.22 |
| 2026-02-08 00:00 |
02:15:13.42 |
+09:26:07.6 |
HIP 10414 |
23.31 |
| 2026-02-08 12:00 |
02:15:13.73 |
+09:26:11.3 |
HIP 10414 |
23.41 |
| 2026-02-09 00:00 |
02:15:14.05 |
+09:26:15.1 |
HIP 10414 |
23.51 |
| 2026-02-09 12:00 |
02:15:14.39 |
+09:26:19.0 |
HIP 10414 |
23.61 |
| 2026-02-10 00:00 |
02:15:14.74 |
+09:26:22.9 |
HIP 10414 |
23.72 |
| 2026-02-10 12:00 |
02:15:15.10 |
+09:26:26.9 |
HIP 10414 |
23.83 |
| 2026-02-11 00:00 |
02:15:15.48 |
+09:26:31.0 |
HIP 10414 |
23.94 |
| 2026-02-11 12:00 |
02:15:15.88 |
+09:26:35.2 |
HIP 10414 |
24.06 |
| 2026-02-12 00:00 |
02:15:16.28 |
+09:26:39.4 |
HIP 10414 |
24.18 |
| 2026-02-12 12:00 |
02:15:16.70 |
+09:26:43.7 |
HIP 10414 |
24.30 |
| 2026-02-13 00:00 |
02:15:17.14 |
+09:26:48.0 |
HIP 10414 |
24.42 |
| 2026-02-13 12:00 |
02:15:17.59 |
+09:26:52.4 |
HIP 10414 |
24.55 |
| 2026-02-14 00:00 |
02:15:18.05 |
+09:26:56.9 |
HIP 10414 |
24.68 |
| 2026-02-14 12:00 |
02:15:18.53 |
+09:27:01.4 |
HIP 10414 |
24.82 |
| 2026-02-15 00:00 |
02:15:19.02 |
+09:27:06.1 |
HIP 10414 |
24.96 |
| 2026-02-15 12:00 |
02:15:19.52 |
+09:27:10.7 |
HIP 10414 |
25.10 |
| 2026-02-16 00:00 |
02:15:20.04 |
+09:27:15.5 |
HIP 10414 |
25.24 |
| 2026-02-16 12:00 |
02:15:20.57 |
+09:27:20.3 |
HIP 10414 |
25.39 |
| 2026-02-17 00:00 |
02:15:21.12 |
+09:27:25.1 |
HIP 10414 |
25.54 |
| 2026-02-17 12:00 |
02:15:21.67 |
+09:27:30.1 |
HIP 10414 |
25.70 |
| 2026-02-18 00:00 |
02:15:22.25 |
+09:27:35.1 |
HIP 10414 |
25.85 |
| 2026-02-18 12:00 |
02:15:22.83 |
+09:27:40.1 |
HIP 10414 |
26.01 |
| 2026-02-19 00:00 |
02:15:23.43 |
+09:27:45.2 |
HIP 10614 |
26.04 |
| 2026-02-19 12:00 |
02:15:24.04 |
+09:27:50.4 |
HIP 10614 |
25.87 |
| 2026-02-20 00:00 |
02:15:24.67 |
+09:27:55.6 |
HIP 10614 |
25.70 |
| 2026-02-20 12:00 |
02:15:25.30 |
+09:28:00.9 |
HIP 10614 |
25.53 |
| 2026-02-21 00:00 |
02:15:25.95 |
+09:28:06.3 |
HIP 10614 |
25.35 |
| 2026-02-21 12:00 |
02:15:26.62 |
+09:28:11.7 |
HIP 10614 |
25.17 |
| 2026-02-22 00:00 |
02:15:27.29 |
+09:28:17.2 |
HIP 10614 |
24.99 |
| 2026-02-22 12:00 |
02:15:27.98 |
+09:28:22.7 |
HIP 10614 |
24.80 |
| 2026-02-23 00:00 |
02:15:28.69 |
+09:28:28.3 |
HIP 10614 |
24.62 |
| 2026-02-23 12:00 |
02:15:29.40 |
+09:28:33.9 |
HIP 10614 |
24.42 |
| 2026-02-24 00:00 |
02:15:30.13 |
+09:28:39.6 |
HIP 10614 |
24.23 |