| Parameter |
Value |
| Designation |
C/2012 J1 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2012-12-07T05:37:22.232640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:08Z |
| Obs used |
4401 |
| NEO |
- |
| M1 |
6.000 |
| K1 |
12.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-11-16.0000000 |
| e |
1.00132777 |
| q (au) |
3.158711 |
| a (au) |
-2378.965648 |
| i (deg) |
34.186089 |
| Ω (om, deg) |
235.217062 |
| ω (w, deg) |
147.272733 |
| M (ma, deg) |
-0.000180 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.312 + 4.942\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.312 |
| n |
4.942 |
| gf |
1.000 |
| gb |
-0.923 |
| 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) |
| 2026-09-20 00:00 |
10:25:21.66 |
-23:41:30.7 |
HIP 51012 |
9.32 |
| 2026-09-20 12:00 |
10:25:25.62 |
-23:42:01.0 |
HIP 51012 |
9.96 |
| 2026-09-21 00:00 |
10:25:29.57 |
-23:42:31.4 |
HIP 51012 |
10.67 |
| 2026-09-21 12:00 |
10:25:33.50 |
-23:43:02.0 |
HIP 51012 |
11.43 |
| 2026-09-22 00:00 |
10:25:37.42 |
-23:43:32.7 |
HIP 51012 |
12.23 |
| 2026-09-22 12:00 |
10:25:41.33 |
-23:44:03.7 |
HIP 51012 |
13.06 |
| 2026-09-23 00:00 |
10:25:45.22 |
-23:44:34.8 |
HIP 51012 |
13.93 |
| 2026-09-23 12:00 |
10:25:49.10 |
-23:45:06.1 |
HIP 51012 |
14.81 |
| 2026-09-24 00:00 |
10:25:52.96 |
-23:45:37.6 |
HIP 51012 |
15.72 |
| 2026-09-24 12:00 |
10:25:56.81 |
-23:46:09.2 |
HIP 51012 |
16.64 |
| 2026-09-25 00:00 |
10:26:00.65 |
-23:46:41.1 |
HIP 51012 |
17.57 |
| 2026-09-25 12:00 |
10:26:04.47 |
-23:47:13.1 |
HIP 51186 |
17.33 |
| 2026-09-26 00:00 |
10:26:08.27 |
-23:47:45.2 |
HIP 51186 |
16.47 |
| 2026-09-26 12:00 |
10:26:12.06 |
-23:48:17.6 |
HIP 51186 |
15.64 |
| 2026-09-27 00:00 |
10:26:15.83 |
-23:48:50.0 |
HIP 51186 |
14.84 |
| 2026-09-27 12:00 |
10:26:19.59 |
-23:49:22.7 |
HIP 51186 |
14.07 |
| 2026-09-28 00:00 |
10:26:23.34 |
-23:49:55.5 |
HIP 51186 |
13.33 |
| 2026-09-28 12:00 |
10:26:27.06 |
-23:50:28.5 |
HIP 51186 |
12.64 |
| 2026-09-29 00:00 |
10:26:30.77 |
-23:51:01.6 |
HIP 51186 |
12.00 |
| 2026-09-29 12:00 |
10:26:34.47 |
-23:51:34.9 |
HIP 51186 |
11.42 |
| 2026-09-30 00:00 |
10:26:38.14 |
-23:52:08.3 |
HIP 51186 |
10.91 |
| 2026-09-30 12:00 |
10:26:41.80 |
-23:52:41.9 |
HIP 51186 |
10.48 |
| 2026-10-01 00:00 |
10:26:45.44 |
-23:53:15.7 |
HIP 51186 |
10.13 |
| 2026-10-01 12:00 |
10:26:49.07 |
-23:53:49.6 |
HIP 51186 |
9.87 |
| 2026-10-02 00:00 |
10:26:52.67 |
-23:54:23.6 |
HIP 51186 |
9.72 |
| 2026-10-02 12:00 |
10:26:56.26 |
-23:54:57.8 |
HIP 51186 |
9.67 |
| 2026-10-03 00:00 |
10:26:59.83 |
-23:55:32.1 |
HIP 51186 |
9.73 |
| 2026-10-03 12:00 |
10:27:03.39 |
-23:56:06.6 |
HIP 51186 |
9.90 |
| 2026-10-04 00:00 |
10:27:06.92 |
-23:56:41.2 |
HIP 51186 |
10.16 |
| 2026-10-04 12:00 |
10:27:10.44 |
-23:57:15.9 |
HIP 51186 |
10.52 |
| 2026-10-05 00:00 |
10:27:13.93 |
-23:57:50.8 |
HIP 51186 |
10.95 |
| 2026-10-05 12:00 |
10:27:17.41 |
-23:58:25.8 |
HIP 51186 |
11.46 |
| 2026-10-06 00:00 |
10:27:20.86 |
-23:59:00.9 |
HIP 51186 |
12.03 |
| 2026-10-06 12:00 |
10:27:24.30 |
-23:59:36.2 |
HIP 51186 |
12.65 |
| 2026-10-07 00:00 |
10:27:27.72 |
-24:00:11.6 |
HIP 51186 |
13.32 |
| 2026-10-07 12:00 |
10:27:31.11 |
-24:00:47.1 |
HIP 51186 |
14.02 |
| 2026-10-08 00:00 |
10:27:34.49 |
-24:01:22.7 |
HIP 51186 |
14.76 |
| 2026-10-08 12:00 |
10:27:37.84 |
-24:01:58.4 |
HIP 51186 |
15.52 |
| 2026-10-09 00:00 |
10:27:41.18 |
-24:02:34.3 |
HIP 51263 |
15.71 |
| 2026-10-09 12:00 |
10:27:44.49 |
-24:03:10.3 |
HIP 51263 |
14.81 |
| 2026-10-10 00:00 |
10:27:47.78 |
-24:03:46.4 |
HIP 51263 |
13.91 |
| 2026-10-10 12:00 |
10:27:51.05 |
-24:04:22.6 |
HIP 51263 |
13.03 |
| 2026-10-11 00:00 |
10:27:54.29 |
-24:04:58.9 |
HIP 51263 |
12.16 |