| 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) |
| 2026-07-29 00:00 |
02:08:52.25 |
+54:57:17.6 |
HIP 10104 |
33.28 |
| 2026-07-29 12:00 |
02:08:52.13 |
+54:57:34.1 |
HIP 10104 |
33.02 |
| 2026-07-30 00:00 |
02:08:51.99 |
+54:57:50.6 |
HIP 10104 |
32.76 |
| 2026-07-30 12:00 |
02:08:51.82 |
+54:58:07.0 |
HIP 10104 |
32.50 |
| 2026-07-31 00:00 |
02:08:51.63 |
+54:58:23.3 |
HIP 10104 |
32.25 |
| 2026-07-31 12:00 |
02:08:51.41 |
+54:58:39.6 |
HIP 10104 |
32.00 |
| 2026-08-01 00:00 |
02:08:51.17 |
+54:58:55.9 |
HIP 10104 |
31.75 |
| 2026-08-01 12:00 |
02:08:50.90 |
+54:59:12.0 |
HIP 10104 |
31.51 |
| 2026-08-02 00:00 |
02:08:50.62 |
+54:59:28.1 |
HIP 10104 |
31.26 |
| 2026-08-02 12:00 |
02:08:50.30 |
+54:59:44.1 |
HIP 10104 |
31.02 |
| 2026-08-03 00:00 |
02:08:49.96 |
+55:00:00.1 |
HIP 10104 |
30.78 |
| 2026-08-03 12:00 |
02:08:49.60 |
+55:00:16.0 |
HIP 10104 |
30.55 |
| 2026-08-04 00:00 |
02:08:49.21 |
+55:00:31.8 |
HIP 10104 |
30.32 |
| 2026-08-04 12:00 |
02:08:48.80 |
+55:00:47.6 |
HIP 10104 |
30.09 |
| 2026-08-05 00:00 |
02:08:48.37 |
+55:01:03.3 |
HIP 10104 |
29.86 |
| 2026-08-05 12:00 |
02:08:47.91 |
+55:01:18.9 |
HIP 10104 |
29.63 |
| 2026-08-06 00:00 |
02:08:47.42 |
+55:01:34.4 |
HIP 10104 |
29.41 |
| 2026-08-06 12:00 |
02:08:46.91 |
+55:01:49.9 |
HIP 10104 |
29.20 |
| 2026-08-07 00:00 |
02:08:46.38 |
+55:02:05.3 |
HIP 10104 |
28.98 |
| 2026-08-07 12:00 |
02:08:45.82 |
+55:02:20.6 |
HIP 10104 |
28.77 |
| 2026-08-08 00:00 |
02:08:45.24 |
+55:02:35.8 |
HIP 10104 |
28.56 |
| 2026-08-08 12:00 |
02:08:44.64 |
+55:02:51.0 |
HIP 10104 |
28.36 |
| 2026-08-09 00:00 |
02:08:44.01 |
+55:03:06.1 |
HIP 10104 |
28.16 |
| 2026-08-09 12:00 |
02:08:43.35 |
+55:03:21.1 |
HIP 10104 |
27.96 |
| 2026-08-10 00:00 |
02:08:42.67 |
+55:03:36.0 |
HIP 10104 |
27.77 |
| 2026-08-10 12:00 |
02:08:41.97 |
+55:03:50.8 |
HIP 10104 |
27.58 |
| 2026-08-11 00:00 |
02:08:41.24 |
+55:04:05.5 |
HIP 10104 |
27.39 |
| 2026-08-11 12:00 |
02:08:40.49 |
+55:04:20.2 |
HIP 10104 |
27.21 |
| 2026-08-12 00:00 |
02:08:39.71 |
+55:04:34.7 |
HIP 10104 |
27.04 |
| 2026-08-12 12:00 |
02:08:38.91 |
+55:04:49.2 |
HIP 10104 |
26.86 |
| 2026-08-13 00:00 |
02:08:38.09 |
+55:05:03.6 |
HIP 10104 |
26.69 |
| 2026-08-13 12:00 |
02:08:37.24 |
+55:05:17.9 |
HIP 10104 |
26.53 |
| 2026-08-14 00:00 |
02:08:36.37 |
+55:05:32.1 |
HIP 10104 |
26.37 |
| 2026-08-14 12:00 |
02:08:35.47 |
+55:05:46.2 |
HIP 10104 |
26.22 |
| 2026-08-15 00:00 |
02:08:34.55 |
+55:06:00.2 |
HIP 10104 |
26.07 |
| 2026-08-15 12:00 |
02:08:33.60 |
+55:06:14.1 |
HIP 10104 |
25.92 |
| 2026-08-16 00:00 |
02:08:32.64 |
+55:06:27.9 |
HIP 10104 |
25.78 |
| 2026-08-16 12:00 |
02:08:31.64 |
+55:06:41.6 |
HIP 10104 |
25.65 |
| 2026-08-17 00:00 |
02:08:30.63 |
+55:06:55.2 |
HIP 10104 |
25.52 |
| 2026-08-17 12:00 |
02:08:29.59 |
+55:07:08.7 |
HIP 10104 |
25.39 |
| 2026-08-18 00:00 |
02:08:28.52 |
+55:07:22.1 |
HIP 10104 |
25.27 |
| 2026-08-18 12:00 |
02:08:27.44 |
+55:07:35.3 |
HIP 10104 |
25.16 |
| 2026-08-19 00:00 |
02:08:26.33 |
+55:07:48.5 |
HIP 10104 |
25.05 |