| 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) |
| 2026-05-12 00:00 |
02:04:55.84 |
+54:15:52.4 |
HIP 9852 |
16.14 |
| 2026-05-12 12:00 |
02:04:58.51 |
+54:16:03.1 |
HIP 9852 |
15.73 |
| 2026-05-13 00:00 |
02:05:01.17 |
+54:16:13.9 |
HIP 9852 |
15.32 |
| 2026-05-13 12:00 |
02:05:03.83 |
+54:16:24.8 |
HIP 9852 |
14.91 |
| 2026-05-14 00:00 |
02:05:06.48 |
+54:16:35.9 |
HIP 9852 |
14.50 |
| 2026-05-14 12:00 |
02:05:09.12 |
+54:16:47.0 |
HIP 9852 |
14.10 |
| 2026-05-15 00:00 |
02:05:11.75 |
+54:16:58.3 |
HIP 9852 |
13.69 |
| 2026-05-15 12:00 |
02:05:14.37 |
+54:17:09.7 |
HIP 9852 |
13.29 |
| 2026-05-16 00:00 |
02:05:16.99 |
+54:17:21.3 |
HIP 9852 |
12.89 |
| 2026-05-16 12:00 |
02:05:19.60 |
+54:17:32.9 |
HIP 9852 |
12.50 |
| 2026-05-17 00:00 |
02:05:22.20 |
+54:17:44.6 |
HIP 9852 |
12.11 |
| 2026-05-17 12:00 |
02:05:24.79 |
+54:17:56.5 |
HIP 9852 |
11.72 |
| 2026-05-18 00:00 |
02:05:27.37 |
+54:18:08.5 |
HIP 9852 |
11.34 |
| 2026-05-18 12:00 |
02:05:29.94 |
+54:18:20.6 |
HIP 9852 |
10.96 |
| 2026-05-19 00:00 |
02:05:32.51 |
+54:18:32.8 |
HIP 9852 |
10.59 |
| 2026-05-19 12:00 |
02:05:35.06 |
+54:18:45.1 |
HIP 9852 |
10.22 |
| 2026-05-20 00:00 |
02:05:37.61 |
+54:18:57.5 |
HIP 9852 |
9.86 |
| 2026-05-20 12:00 |
02:05:40.14 |
+54:19:10.0 |
HIP 9852 |
9.50 |
| 2026-05-21 00:00 |
02:05:42.66 |
+54:19:22.6 |
HIP 9852 |
9.15 |
| 2026-05-21 12:00 |
02:05:45.18 |
+54:19:35.3 |
HIP 9852 |
8.81 |
| 2026-05-22 00:00 |
02:05:47.68 |
+54:19:48.2 |
HIP 9852 |
8.49 |
| 2026-05-22 12:00 |
02:05:50.18 |
+54:20:01.1 |
HIP 9852 |
8.17 |
| 2026-05-23 00:00 |
02:05:52.66 |
+54:20:14.1 |
HIP 9852 |
7.86 |
| 2026-05-23 12:00 |
02:05:55.13 |
+54:20:27.3 |
HIP 9852 |
7.57 |
| 2026-05-24 00:00 |
02:05:57.59 |
+54:20:40.5 |
HIP 9852 |
7.29 |
| 2026-05-24 12:00 |
02:06:00.04 |
+54:20:53.8 |
HIP 9852 |
7.02 |
| 2026-05-25 00:00 |
02:06:02.48 |
+54:21:07.3 |
HIP 9852 |
6.78 |
| 2026-05-25 12:00 |
02:06:04.90 |
+54:21:20.8 |
HIP 9852 |
6.55 |
| 2026-05-26 00:00 |
02:06:07.32 |
+54:21:34.4 |
HIP 9852 |
6.35 |
| 2026-05-26 12:00 |
02:06:09.72 |
+54:21:48.1 |
HIP 9852 |
6.17 |
| 2026-05-27 00:00 |
02:06:12.11 |
+54:22:01.9 |
HIP 9852 |
6.02 |
| 2026-05-27 12:00 |
02:06:14.49 |
+54:22:15.8 |
HIP 9852 |
5.89 |
| 2026-05-28 00:00 |
02:06:16.86 |
+54:22:29.8 |
HIP 9852 |
5.80 |
| 2026-05-28 12:00 |
02:06:19.21 |
+54:22:43.9 |
HIP 9852 |
5.74 |
| 2026-05-29 00:00 |
02:06:21.55 |
+54:22:58.1 |
HIP 9852 |
5.71 |
| 2026-05-29 12:00 |
02:06:23.88 |
+54:23:12.3 |
HIP 9852 |
5.71 |
| 2026-05-30 00:00 |
02:06:26.20 |
+54:23:26.7 |
HIP 9852 |
5.74 |
| 2026-05-30 12:00 |
02:06:28.50 |
+54:23:41.1 |
HIP 9852 |
5.80 |
| 2026-05-31 00:00 |
02:06:30.79 |
+54:23:55.6 |
HIP 9852 |
5.90 |
| 2026-05-31 12:00 |
02:06:33.07 |
+54:24:10.3 |
HIP 9852 |
6.02 |
| 2026-06-01 00:00 |
02:06:35.33 |
+54:24:24.9 |
HIP 9852 |
6.17 |
| 2026-06-01 12:00 |
02:06:37.58 |
+54:24:39.7 |
HIP 9852 |
6.35 |
| 2026-06-02 00:00 |
02:06:39.81 |
+54:24:54.6 |
HIP 9852 |
6.55 |