| Parameter |
Value |
| Designation |
C/1983 H1 (IRAS-Araki-Alcock) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1983-05-21T06:06:31.124160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:29Z |
| Obs used |
347 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1983-05-13.0000000 |
| e |
0.98988782 |
| q (au) |
0.991341 |
| a (au) |
98.034357 |
| i (deg) |
73.251379 |
| Ω (om, deg) |
49.102458 |
| ω (w, deg) |
192.850689 |
| M (ma, deg) |
359.991618 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.784 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.784 |
| n |
6.000 |
| gf |
0.800 |
| gb |
-0.513 |
| k |
0.800 |
| δ90 |
1.000 |
| 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) |
| 2026-07-29 00:00 |
03:10:30.15 |
+18:48:36.2 |
HIP 14675 |
18.48 |
| 2026-07-29 12:00 |
03:10:30.59 |
+18:48:39.1 |
HIP 14675 |
18.52 |
| 2026-07-30 00:00 |
03:10:31.03 |
+18:48:41.9 |
HIP 14675 |
18.56 |
| 2026-07-30 12:00 |
03:10:31.45 |
+18:48:44.7 |
HIP 14675 |
18.60 |
| 2026-07-31 00:00 |
03:10:31.85 |
+18:48:47.4 |
HIP 14675 |
18.63 |
| 2026-07-31 12:00 |
03:10:32.23 |
+18:48:50.1 |
HIP 14675 |
18.67 |
| 2026-08-01 00:00 |
03:10:32.61 |
+18:48:52.7 |
HIP 14675 |
18.70 |
| 2026-08-01 12:00 |
03:10:32.96 |
+18:48:55.2 |
HIP 14675 |
18.73 |
| 2026-08-02 00:00 |
03:10:33.30 |
+18:48:57.7 |
HIP 14675 |
18.76 |
| 2026-08-02 12:00 |
03:10:33.63 |
+18:49:00.1 |
HIP 14675 |
18.79 |
| 2026-08-03 00:00 |
03:10:33.94 |
+18:49:02.4 |
HIP 14675 |
18.81 |
| 2026-08-03 12:00 |
03:10:34.23 |
+18:49:04.7 |
HIP 14675 |
18.84 |
| 2026-08-04 00:00 |
03:10:34.51 |
+18:49:07.0 |
HIP 14675 |
18.86 |
| 2026-08-04 12:00 |
03:10:34.77 |
+18:49:09.1 |
HIP 14675 |
18.88 |
| 2026-08-05 00:00 |
03:10:35.02 |
+18:49:11.2 |
HIP 14675 |
18.90 |
| 2026-08-05 12:00 |
03:10:35.25 |
+18:49:13.3 |
HIP 14675 |
18.92 |
| 2026-08-06 00:00 |
03:10:35.46 |
+18:49:15.3 |
HIP 14675 |
18.94 |
| 2026-08-06 12:00 |
03:10:35.66 |
+18:49:17.2 |
HIP 14675 |
18.95 |
| 2026-08-07 00:00 |
03:10:35.85 |
+18:49:19.0 |
HIP 14675 |
18.96 |
| 2026-08-07 12:00 |
03:10:36.02 |
+18:49:20.8 |
HIP 14675 |
18.97 |
| 2026-08-08 00:00 |
03:10:36.17 |
+18:49:22.6 |
HIP 14675 |
18.98 |
| 2026-08-08 12:00 |
03:10:36.30 |
+18:49:24.3 |
HIP 14675 |
18.98 |
| 2026-08-09 00:00 |
03:10:36.42 |
+18:49:25.9 |
HIP 14675 |
18.99 |
| 2026-08-09 12:00 |
03:10:36.53 |
+18:49:27.4 |
HIP 14675 |
18.99 |
| 2026-08-10 00:00 |
03:10:36.62 |
+18:49:28.9 |
HIP 14675 |
18.99 |
| 2026-08-10 12:00 |
03:10:36.69 |
+18:49:30.3 |
HIP 14675 |
18.99 |
| 2026-08-11 00:00 |
03:10:36.75 |
+18:49:31.7 |
HIP 14675 |
18.98 |
| 2026-08-11 12:00 |
03:10:36.79 |
+18:49:33.0 |
HIP 14675 |
18.97 |
| 2026-08-12 00:00 |
03:10:36.81 |
+18:49:34.2 |
HIP 14675 |
18.97 |
| 2026-08-12 12:00 |
03:10:36.82 |
+18:49:35.4 |
HIP 14675 |
18.95 |
| 2026-08-13 00:00 |
03:10:36.81 |
+18:49:36.5 |
HIP 14675 |
18.94 |
| 2026-08-13 12:00 |
03:10:36.78 |
+18:49:37.6 |
HIP 14675 |
18.93 |
| 2026-08-14 00:00 |
03:10:36.74 |
+18:49:38.5 |
HIP 14675 |
18.91 |
| 2026-08-14 12:00 |
03:10:36.69 |
+18:49:39.5 |
HIP 14675 |
18.89 |
| 2026-08-15 00:00 |
03:10:36.61 |
+18:49:40.3 |
HIP 14675 |
18.86 |
| 2026-08-15 12:00 |
03:10:36.53 |
+18:49:41.1 |
HIP 14675 |
18.84 |
| 2026-08-16 00:00 |
03:10:36.42 |
+18:49:41.8 |
HIP 14675 |
18.81 |
| 2026-08-16 12:00 |
03:10:36.30 |
+18:49:42.5 |
HIP 14675 |
18.78 |
| 2026-08-17 00:00 |
03:10:36.16 |
+18:49:43.1 |
HIP 14675 |
18.75 |
| 2026-08-17 12:00 |
03:10:36.01 |
+18:49:43.6 |
HIP 14675 |
18.72 |
| 2026-08-18 00:00 |
03:10:35.84 |
+18:49:44.1 |
HIP 14675 |
18.68 |
| 2026-08-18 12:00 |
03:10:35.65 |
+18:49:44.5 |
HIP 14675 |
18.65 |
| 2026-08-19 00:00 |
03:10:35.45 |
+18:49:44.8 |
HIP 14675 |
18.61 |