| 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) |
| 2026-05-12 00:00 |
03:06:58.30 |
+18:32:09.1 |
HIP 14391 |
20.86 |
| 2026-05-12 12:00 |
03:07:00.16 |
+18:32:17.2 |
HIP 14391 |
21.20 |
| 2026-05-13 00:00 |
03:07:02.03 |
+18:32:25.4 |
HIP 14391 |
21.54 |
| 2026-05-13 12:00 |
03:07:03.89 |
+18:32:33.5 |
HIP 14391 |
21.89 |
| 2026-05-14 00:00 |
03:07:05.76 |
+18:32:41.7 |
HIP 14391 |
22.24 |
| 2026-05-14 12:00 |
03:07:07.62 |
+18:32:49.9 |
HIP 14391 |
22.59 |
| 2026-05-15 00:00 |
03:07:09.48 |
+18:32:58.0 |
HIP 14586 |
22.47 |
| 2026-05-15 12:00 |
03:07:11.35 |
+18:33:06.1 |
HIP 14586 |
22.05 |
| 2026-05-16 00:00 |
03:07:13.21 |
+18:33:14.3 |
HIP 14586 |
21.63 |
| 2026-05-16 12:00 |
03:07:15.06 |
+18:33:22.4 |
HIP 14586 |
21.21 |
| 2026-05-17 00:00 |
03:07:16.92 |
+18:33:30.6 |
HIP 14586 |
20.80 |
| 2026-05-17 12:00 |
03:07:18.78 |
+18:33:38.7 |
HIP 14586 |
20.38 |
| 2026-05-18 00:00 |
03:07:20.63 |
+18:33:46.8 |
HIP 14586 |
19.97 |
| 2026-05-18 12:00 |
03:07:22.48 |
+18:33:54.9 |
HIP 14586 |
19.57 |
| 2026-05-19 00:00 |
03:07:24.33 |
+18:34:03.1 |
HIP 14586 |
19.16 |
| 2026-05-19 12:00 |
03:07:26.17 |
+18:34:11.2 |
HIP 14586 |
18.76 |
| 2026-05-20 00:00 |
03:07:28.02 |
+18:34:19.3 |
HIP 14586 |
18.36 |
| 2026-05-20 12:00 |
03:07:29.86 |
+18:34:27.4 |
HIP 14586 |
17.96 |
| 2026-05-21 00:00 |
03:07:31.70 |
+18:34:35.4 |
HIP 14586 |
17.57 |
| 2026-05-21 12:00 |
03:07:33.53 |
+18:34:43.5 |
HIP 14586 |
17.18 |
| 2026-05-22 00:00 |
03:07:35.37 |
+18:34:51.6 |
HIP 14586 |
16.80 |
| 2026-05-22 12:00 |
03:07:37.20 |
+18:34:59.6 |
HIP 14586 |
16.42 |
| 2026-05-23 00:00 |
03:07:39.02 |
+18:35:07.7 |
HIP 14586 |
16.04 |
| 2026-05-23 12:00 |
03:07:40.85 |
+18:35:15.7 |
HIP 14586 |
15.67 |
| 2026-05-24 00:00 |
03:07:42.67 |
+18:35:23.8 |
HIP 14586 |
15.31 |
| 2026-05-24 12:00 |
03:07:44.48 |
+18:35:31.8 |
HIP 14586 |
14.95 |
| 2026-05-25 00:00 |
03:07:46.29 |
+18:35:39.8 |
HIP 14586 |
14.59 |
| 2026-05-25 12:00 |
03:07:48.10 |
+18:35:47.8 |
HIP 14586 |
14.24 |
| 2026-05-26 00:00 |
03:07:49.91 |
+18:35:55.7 |
HIP 14586 |
13.90 |
| 2026-05-26 12:00 |
03:07:51.71 |
+18:36:03.7 |
HIP 14586 |
13.56 |
| 2026-05-27 00:00 |
03:07:53.50 |
+18:36:11.6 |
HIP 14586 |
13.24 |
| 2026-05-27 12:00 |
03:07:55.29 |
+18:36:19.6 |
HIP 14586 |
12.91 |
| 2026-05-28 00:00 |
03:07:57.08 |
+18:36:27.5 |
HIP 14586 |
12.60 |
| 2026-05-28 12:00 |
03:07:58.87 |
+18:36:35.4 |
HIP 14586 |
12.30 |
| 2026-05-29 00:00 |
03:08:00.64 |
+18:36:43.3 |
HIP 14586 |
12.00 |
| 2026-05-29 12:00 |
03:08:02.42 |
+18:36:51.2 |
HIP 14586 |
11.72 |
| 2026-05-30 00:00 |
03:08:04.19 |
+18:36:59.0 |
HIP 14586 |
11.44 |
| 2026-05-30 12:00 |
03:08:05.95 |
+18:37:06.9 |
HIP 14586 |
11.18 |
| 2026-05-31 00:00 |
03:08:07.71 |
+18:37:14.7 |
HIP 14586 |
10.93 |
| 2026-05-31 12:00 |
03:08:09.46 |
+18:37:22.5 |
HIP 14586 |
10.69 |
| 2026-06-01 00:00 |
03:08:11.21 |
+18:37:30.3 |
HIP 14586 |
10.47 |
| 2026-06-01 12:00 |
03:08:12.95 |
+18:37:38.0 |
HIP 14586 |
10.25 |
| 2026-06-02 00:00 |
03:08:14.69 |
+18:37:45.8 |
HIP 14586 |
10.06 |