| Parameter |
Value |
| Designation |
C/1983 O2 (IRAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1983-11-28T00:05:51.535680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
35 |
| NEO |
- |
| M1 |
9.400 |
| K1 |
10.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1984-02-25.0000000 |
| e |
1.00012977 |
| q (au) |
2.254797 |
| a (au) |
-17374.673642 |
| i (deg) |
120.736009 |
| Ω (om, deg) |
201.257657 |
| ω (w, deg) |
333.980548 |
| M (ma, deg) |
0.000038 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.786 + 5.716\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.786 |
| n |
5.716 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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) |
| 2026-09-25 00:00 |
02:06:05.92 |
+55:18:05.8 |
HIP 9723 |
21.16 |
| 2026-09-25 12:00 |
02:06:03.35 |
+55:18:08.5 |
HIP 9723 |
20.97 |
| 2026-09-26 00:00 |
02:06:00.78 |
+55:18:11.1 |
HIP 9723 |
20.79 |
| 2026-09-26 12:00 |
02:05:58.19 |
+55:18:13.5 |
HIP 9723 |
20.61 |
| 2026-09-27 00:00 |
02:05:55.58 |
+55:18:15.7 |
HIP 9723 |
20.44 |
| 2026-09-27 12:00 |
02:05:52.97 |
+55:18:17.7 |
HIP 9723 |
20.28 |
| 2026-09-28 00:00 |
02:05:50.34 |
+55:18:19.6 |
HIP 9723 |
20.13 |
| 2026-09-28 12:00 |
02:05:47.70 |
+55:18:21.4 |
HIP 9723 |
19.98 |
| 2026-09-29 00:00 |
02:05:45.04 |
+55:18:22.9 |
HIP 9723 |
19.84 |
| 2026-09-29 12:00 |
02:05:42.38 |
+55:18:24.3 |
HIP 9723 |
19.71 |
| 2026-09-30 00:00 |
02:05:39.70 |
+55:18:25.5 |
HIP 9723 |
19.59 |
| 2026-09-30 12:00 |
02:05:37.01 |
+55:18:26.6 |
HIP 9723 |
19.48 |
| 2026-10-01 00:00 |
02:05:34.31 |
+55:18:27.5 |
HIP 9723 |
19.37 |
| 2026-10-01 12:00 |
02:05:31.59 |
+55:18:28.2 |
HIP 9723 |
19.28 |
| 2026-10-02 00:00 |
02:05:28.87 |
+55:18:28.8 |
HIP 9723 |
19.19 |
| 2026-10-02 12:00 |
02:05:26.13 |
+55:18:29.1 |
HIP 9723 |
19.12 |
| 2026-10-03 00:00 |
02:05:23.39 |
+55:18:29.4 |
HIP 9723 |
19.06 |
| 2026-10-03 12:00 |
02:05:20.63 |
+55:18:29.4 |
HIP 9723 |
19.00 |
| 2026-10-04 00:00 |
02:05:17.86 |
+55:18:29.3 |
HIP 9582 |
18.86 |
| 2026-10-04 12:00 |
02:05:15.08 |
+55:18:29.0 |
HIP 9582 |
18.47 |
| 2026-10-05 00:00 |
02:05:12.29 |
+55:18:28.5 |
HIP 9582 |
18.09 |
| 2026-10-05 12:00 |
02:05:09.49 |
+55:18:27.9 |
HIP 9582 |
17.70 |
| 2026-10-06 00:00 |
02:05:06.68 |
+55:18:27.0 |
HIP 9582 |
17.31 |
| 2026-10-06 12:00 |
02:05:03.87 |
+55:18:26.1 |
HIP 9582 |
16.92 |
| 2026-10-07 00:00 |
02:05:01.04 |
+55:18:24.9 |
HIP 9582 |
16.52 |
| 2026-10-07 12:00 |
02:04:58.20 |
+55:18:23.6 |
HIP 9582 |
16.13 |
| 2026-10-08 00:00 |
02:04:55.36 |
+55:18:22.1 |
HIP 9582 |
15.73 |
| 2026-10-08 12:00 |
02:04:52.50 |
+55:18:20.4 |
HIP 9582 |
15.33 |
| 2026-10-09 00:00 |
02:04:49.64 |
+55:18:18.5 |
HIP 9582 |
14.94 |
| 2026-10-09 12:00 |
02:04:46.77 |
+55:18:16.5 |
HIP 9582 |
14.53 |
| 2026-10-10 00:00 |
02:04:43.89 |
+55:18:14.3 |
HIP 9582 |
14.13 |
| 2026-10-10 12:00 |
02:04:41.00 |
+55:18:12.0 |
HIP 9582 |
13.73 |
| 2026-10-11 00:00 |
02:04:38.11 |
+55:18:09.4 |
HIP 9582 |
13.32 |
| 2026-10-11 12:00 |
02:04:35.21 |
+55:18:06.7 |
HIP 9582 |
12.92 |
| 2026-10-12 00:00 |
02:04:32.30 |
+55:18:03.8 |
HIP 9582 |
12.51 |
| 2026-10-12 12:00 |
02:04:29.39 |
+55:18:00.8 |
HIP 9582 |
12.10 |
| 2026-10-13 00:00 |
02:04:26.47 |
+55:17:57.6 |
HIP 9582 |
11.69 |
| 2026-10-13 12:00 |
02:04:23.54 |
+55:17:54.2 |
HIP 9582 |
11.28 |
| 2026-10-14 00:00 |
02:04:20.61 |
+55:17:50.6 |
HIP 9582 |
10.87 |
| 2026-10-14 12:00 |
02:04:17.67 |
+55:17:46.8 |
HIP 9582 |
10.46 |
| 2026-10-15 00:00 |
02:04:14.72 |
+55:17:42.9 |
HIP 9582 |
10.05 |
| 2026-10-15 12:00 |
02:04:11.77 |
+55:17:38.8 |
HIP 9582 |
9.63 |
| 2026-10-16 00:00 |
02:04:08.82 |
+55:17:34.6 |
HIP 9582 |
9.22 |