| 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) |
| 2026-03-26 00:00 |
03:04:18.25 |
+18:20:37.6 |
HIP 14403 |
23.33 |
| 2026-03-26 12:00 |
03:04:19.62 |
+18:20:43.5 |
HIP 14403 |
23.08 |
| 2026-03-27 00:00 |
03:04:20.99 |
+18:20:49.4 |
HIP 14403 |
22.83 |
| 2026-03-27 12:00 |
03:04:22.38 |
+18:20:55.4 |
HIP 14403 |
22.58 |
| 2026-03-28 00:00 |
03:04:23.77 |
+18:21:01.3 |
HIP 14403 |
22.33 |
| 2026-03-28 12:00 |
03:04:25.18 |
+18:21:07.4 |
HIP 14403 |
22.08 |
| 2026-03-29 00:00 |
03:04:26.59 |
+18:21:13.5 |
HIP 14403 |
21.83 |
| 2026-03-29 12:00 |
03:04:28.02 |
+18:21:19.6 |
HIP 14403 |
21.59 |
| 2026-03-30 00:00 |
03:04:29.46 |
+18:21:25.8 |
HIP 14403 |
21.34 |
| 2026-03-30 12:00 |
03:04:30.91 |
+18:21:32.0 |
HIP 14403 |
21.10 |
| 2026-03-31 00:00 |
03:04:32.36 |
+18:21:38.2 |
HIP 14403 |
20.85 |
| 2026-03-31 12:00 |
03:04:33.83 |
+18:21:44.5 |
HIP 14403 |
20.61 |
| 2026-04-01 00:00 |
03:04:35.30 |
+18:21:50.9 |
HIP 14403 |
20.37 |
| 2026-04-01 12:00 |
03:04:36.79 |
+18:21:57.3 |
HIP 14403 |
20.14 |
| 2026-04-02 00:00 |
03:04:38.29 |
+18:22:03.7 |
HIP 14403 |
19.90 |
| 2026-04-02 12:00 |
03:04:39.79 |
+18:22:10.1 |
HIP 14403 |
19.67 |
| 2026-04-03 00:00 |
03:04:41.30 |
+18:22:16.6 |
HIP 14403 |
19.44 |
| 2026-04-03 12:00 |
03:04:42.83 |
+18:22:23.2 |
HIP 14403 |
19.22 |
| 2026-04-04 00:00 |
03:04:44.36 |
+18:22:29.8 |
HIP 14403 |
19.00 |
| 2026-04-04 12:00 |
03:04:45.90 |
+18:22:36.4 |
HIP 14403 |
18.78 |
| 2026-04-05 00:00 |
03:04:47.45 |
+18:22:43.1 |
HIP 14403 |
18.57 |
| 2026-04-05 12:00 |
03:04:49.01 |
+18:22:49.8 |
HIP 14403 |
18.36 |
| 2026-04-06 00:00 |
03:04:50.58 |
+18:22:56.5 |
HIP 14403 |
18.15 |
| 2026-04-06 12:00 |
03:04:52.15 |
+18:23:03.3 |
HIP 14403 |
17.95 |
| 2026-04-07 00:00 |
03:04:53.74 |
+18:23:10.1 |
HIP 14403 |
17.76 |
| 2026-04-07 12:00 |
03:04:55.33 |
+18:23:16.9 |
HIP 14403 |
17.57 |
| 2026-04-08 00:00 |
03:04:56.93 |
+18:23:23.8 |
HIP 14403 |
17.39 |
| 2026-04-08 12:00 |
03:04:58.54 |
+18:23:30.8 |
HIP 14403 |
17.21 |
| 2026-04-09 00:00 |
03:05:00.16 |
+18:23:37.7 |
HIP 14403 |
17.04 |
| 2026-04-09 12:00 |
03:05:01.79 |
+18:23:44.7 |
HIP 14403 |
16.88 |
| 2026-04-10 00:00 |
03:05:03.42 |
+18:23:51.7 |
HIP 14403 |
16.73 |
| 2026-04-10 12:00 |
03:05:05.06 |
+18:23:58.8 |
HIP 14403 |
16.58 |
| 2026-04-11 00:00 |
03:05:06.71 |
+18:24:05.9 |
HIP 14403 |
16.44 |
| 2026-04-11 12:00 |
03:05:08.36 |
+18:24:13.0 |
HIP 14403 |
16.31 |
| 2026-04-12 00:00 |
03:05:10.03 |
+18:24:20.2 |
HIP 14403 |
16.19 |
| 2026-04-12 12:00 |
03:05:11.70 |
+18:24:27.4 |
HIP 14403 |
16.08 |
| 2026-04-13 00:00 |
03:05:13.37 |
+18:24:34.6 |
HIP 14403 |
15.98 |
| 2026-04-13 12:00 |
03:05:15.06 |
+18:24:41.8 |
HIP 14403 |
15.88 |
| 2026-04-14 00:00 |
03:05:16.75 |
+18:24:49.1 |
HIP 14403 |
15.80 |
| 2026-04-14 12:00 |
03:05:18.44 |
+18:24:56.4 |
HIP 14403 |
15.73 |
| 2026-04-15 00:00 |
03:05:20.15 |
+18:25:03.8 |
HIP 14403 |
15.67 |
| 2026-04-15 12:00 |
03:05:21.86 |
+18:25:11.1 |
HIP 14403 |
15.62 |
| 2026-04-16 00:00 |
03:05:23.58 |
+18:25:18.5 |
HIP 14403 |
15.58 |