| Parameter |
Value |
| Designation |
C/1983 J2 (IRAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1983-01-18T15:30:12.680640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
7 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1983-05-30.0000000 |
| e |
0.99471612 |
| q (au) |
1.416663 |
| a (au) |
268.110599 |
| i (deg) |
152.173465 |
| Ω (om, deg) |
119.690042 |
| ω (w, deg) |
227.019078 |
| M (ma, deg) |
0.029490 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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) |
| 2026-09-20 00:00 |
06:11:40.35 |
+37:25:38.1 |
HIP 29238 |
23.13 |
| 2026-09-20 12:00 |
06:11:40.48 |
+37:25:44.7 |
HIP 29238 |
23.11 |
| 2026-09-21 00:00 |
06:11:40.59 |
+37:25:51.4 |
HIP 29238 |
23.09 |
| 2026-09-21 12:00 |
06:11:40.68 |
+37:25:58.1 |
HIP 29238 |
23.07 |
| 2026-09-22 00:00 |
06:11:40.76 |
+37:26:04.7 |
HIP 29238 |
23.04 |
| 2026-09-22 12:00 |
06:11:40.81 |
+37:26:11.4 |
HIP 29238 |
23.01 |
| 2026-09-23 00:00 |
06:11:40.85 |
+37:26:18.1 |
HIP 29238 |
22.98 |
| 2026-09-23 12:00 |
06:11:40.87 |
+37:26:24.9 |
HIP 29238 |
22.95 |
| 2026-09-24 00:00 |
06:11:40.86 |
+37:26:31.6 |
HIP 29238 |
22.91 |
| 2026-09-24 12:00 |
06:11:40.84 |
+37:26:38.3 |
HIP 29238 |
22.87 |
| 2026-09-25 00:00 |
06:11:40.80 |
+37:26:45.0 |
HIP 29238 |
22.82 |
| 2026-09-25 12:00 |
06:11:40.74 |
+37:26:51.8 |
HIP 29238 |
22.77 |
| 2026-09-26 00:00 |
06:11:40.67 |
+37:26:58.5 |
HIP 29238 |
22.72 |
| 2026-09-26 12:00 |
06:11:40.57 |
+37:27:05.3 |
HIP 29238 |
22.67 |
| 2026-09-27 00:00 |
06:11:40.45 |
+37:27:12.0 |
HIP 29238 |
22.61 |
| 2026-09-27 12:00 |
06:11:40.32 |
+37:27:18.8 |
HIP 29238 |
22.55 |
| 2026-09-28 00:00 |
06:11:40.16 |
+37:27:25.6 |
HIP 29238 |
22.48 |
| 2026-09-28 12:00 |
06:11:39.99 |
+37:27:32.4 |
HIP 29238 |
22.42 |
| 2026-09-29 00:00 |
06:11:39.80 |
+37:27:39.1 |
HIP 29238 |
22.35 |
| 2026-09-29 12:00 |
06:11:39.58 |
+37:27:45.9 |
HIP 29238 |
22.27 |
| 2026-09-30 00:00 |
06:11:39.35 |
+37:27:52.7 |
HIP 29238 |
22.20 |
| 2026-09-30 12:00 |
06:11:39.10 |
+37:27:59.5 |
HIP 29238 |
22.12 |
| 2026-10-01 00:00 |
06:11:38.83 |
+37:28:06.3 |
HIP 29238 |
22.03 |
| 2026-10-01 12:00 |
06:11:38.55 |
+37:28:13.1 |
HIP 29238 |
21.95 |
| 2026-10-02 00:00 |
06:11:38.24 |
+37:28:19.8 |
HIP 29238 |
21.86 |
| 2026-10-02 12:00 |
06:11:37.91 |
+37:28:26.6 |
HIP 29238 |
21.76 |
| 2026-10-03 00:00 |
06:11:37.57 |
+37:28:33.4 |
HIP 29238 |
21.67 |
| 2026-10-03 12:00 |
06:11:37.20 |
+37:28:40.2 |
HIP 29238 |
21.57 |
| 2026-10-04 00:00 |
06:11:36.82 |
+37:28:47.0 |
HIP 29238 |
21.46 |
| 2026-10-04 12:00 |
06:11:36.41 |
+37:28:53.8 |
HIP 29238 |
21.36 |
| 2026-10-05 00:00 |
06:11:35.99 |
+37:29:00.6 |
HIP 29238 |
21.25 |
| 2026-10-05 12:00 |
06:11:35.55 |
+37:29:07.4 |
HIP 29238 |
21.13 |
| 2026-10-06 00:00 |
06:11:35.08 |
+37:29:14.1 |
HIP 29238 |
21.02 |
| 2026-10-06 12:00 |
06:11:34.60 |
+37:29:20.9 |
HIP 29238 |
20.90 |
| 2026-10-07 00:00 |
06:11:34.10 |
+37:29:27.7 |
HIP 29238 |
20.77 |
| 2026-10-07 12:00 |
06:11:33.58 |
+37:29:34.5 |
HIP 29238 |
20.65 |
| 2026-10-08 00:00 |
06:11:33.05 |
+37:29:41.2 |
HIP 29238 |
20.52 |
| 2026-10-08 12:00 |
06:11:32.49 |
+37:29:48.0 |
HIP 29238 |
20.39 |
| 2026-10-09 00:00 |
06:11:31.91 |
+37:29:54.7 |
HIP 29238 |
20.25 |
| 2026-10-09 12:00 |
06:11:31.32 |
+37:30:01.5 |
HIP 29238 |
20.11 |
| 2026-10-10 00:00 |
06:11:30.70 |
+37:30:08.2 |
HIP 29238 |
19.97 |
| 2026-10-10 12:00 |
06:11:30.07 |
+37:30:14.9 |
HIP 29238 |
19.82 |
| 2026-10-11 00:00 |
06:11:29.41 |
+37:30:21.7 |
HIP 29238 |
19.67 |