| 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) |
| 2026-05-12 00:00 |
06:04:42.99 |
+37:17:11.5 |
HIP 28727 |
9.63 |
| 2026-05-12 12:00 |
06:04:44.61 |
+37:17:07.6 |
HIP 28727 |
9.86 |
| 2026-05-13 00:00 |
06:04:46.24 |
+37:17:03.7 |
HIP 28727 |
10.09 |
| 2026-05-13 12:00 |
06:04:47.89 |
+37:16:59.8 |
HIP 28727 |
10.33 |
| 2026-05-14 00:00 |
06:04:49.54 |
+37:16:55.9 |
HIP 28727 |
10.58 |
| 2026-05-14 12:00 |
06:04:51.21 |
+37:16:52.1 |
HIP 28727 |
10.83 |
| 2026-05-15 00:00 |
06:04:52.89 |
+37:16:48.4 |
HIP 28727 |
11.09 |
| 2026-05-15 12:00 |
06:04:54.58 |
+37:16:44.6 |
HIP 28727 |
11.36 |
| 2026-05-16 00:00 |
06:04:56.28 |
+37:16:41.0 |
HIP 28727 |
11.63 |
| 2026-05-16 12:00 |
06:04:57.99 |
+37:16:37.3 |
HIP 28727 |
11.91 |
| 2026-05-17 00:00 |
06:04:59.71 |
+37:16:33.7 |
HIP 28727 |
12.20 |
| 2026-05-17 12:00 |
06:05:01.44 |
+37:16:30.2 |
HIP 28727 |
12.49 |
| 2026-05-18 00:00 |
06:05:03.19 |
+37:16:26.6 |
HIP 28727 |
12.79 |
| 2026-05-18 12:00 |
06:05:04.94 |
+37:16:23.2 |
HIP 28727 |
13.09 |
| 2026-05-19 00:00 |
06:05:06.70 |
+37:16:19.7 |
HIP 28727 |
13.39 |
| 2026-05-19 12:00 |
06:05:08.47 |
+37:16:16.4 |
HIP 28727 |
13.70 |
| 2026-05-20 00:00 |
06:05:10.26 |
+37:16:13.0 |
HIP 28727 |
14.02 |
| 2026-05-20 12:00 |
06:05:12.05 |
+37:16:09.7 |
HIP 28727 |
14.33 |
| 2026-05-21 00:00 |
06:05:13.85 |
+37:16:06.4 |
HIP 28727 |
14.66 |
| 2026-05-21 12:00 |
06:05:15.66 |
+37:16:03.2 |
HIP 28727 |
14.98 |
| 2026-05-22 00:00 |
06:05:17.48 |
+37:16:00.1 |
HIP 28727 |
15.31 |
| 2026-05-22 12:00 |
06:05:19.31 |
+37:15:56.9 |
HIP 28727 |
15.65 |
| 2026-05-23 00:00 |
06:05:21.15 |
+37:15:53.8 |
HIP 28727 |
15.98 |
| 2026-05-23 12:00 |
06:05:23.00 |
+37:15:50.8 |
HIP 28727 |
16.32 |
| 2026-05-24 00:00 |
06:05:24.85 |
+37:15:47.8 |
HIP 28727 |
16.67 |
| 2026-05-24 12:00 |
06:05:26.72 |
+37:15:44.9 |
HIP 28727 |
17.01 |
| 2026-05-25 00:00 |
06:05:28.59 |
+37:15:41.9 |
HIP 28727 |
17.36 |
| 2026-05-25 12:00 |
06:05:30.47 |
+37:15:39.1 |
HIP 28727 |
17.71 |
| 2026-05-26 00:00 |
06:05:32.36 |
+37:15:36.3 |
HIP 28727 |
18.07 |
| 2026-05-26 12:00 |
06:05:34.26 |
+37:15:33.5 |
HIP 28727 |
18.43 |
| 2026-05-27 00:00 |
06:05:36.16 |
+37:15:30.8 |
HIP 28727 |
18.79 |
| 2026-05-27 12:00 |
06:05:38.08 |
+37:15:28.1 |
HIP 29003 |
19.14 |
| 2026-05-28 00:00 |
06:05:40.00 |
+37:15:25.4 |
HIP 29003 |
18.76 |
| 2026-05-28 12:00 |
06:05:41.92 |
+37:15:22.8 |
HIP 29003 |
18.38 |
| 2026-05-29 00:00 |
06:05:43.86 |
+37:15:20.3 |
HIP 29003 |
18.00 |
| 2026-05-29 12:00 |
06:05:45.80 |
+37:15:17.8 |
HIP 29003 |
17.62 |
| 2026-05-30 00:00 |
06:05:47.75 |
+37:15:15.3 |
HIP 29003 |
17.24 |
| 2026-05-30 12:00 |
06:05:49.70 |
+37:15:12.9 |
HIP 29003 |
16.85 |
| 2026-05-31 00:00 |
06:05:51.67 |
+37:15:10.6 |
HIP 29003 |
16.47 |
| 2026-05-31 12:00 |
06:05:53.64 |
+37:15:08.3 |
HIP 29003 |
16.09 |
| 2026-06-01 00:00 |
06:05:55.61 |
+37:15:06.0 |
HIP 29003 |
15.70 |
| 2026-06-01 12:00 |
06:05:57.59 |
+37:15:03.8 |
HIP 29003 |
15.32 |
| 2026-06-02 00:00 |
06:05:59.58 |
+37:15:01.6 |
HIP 29003 |
14.94 |