| Parameter |
Value |
| Designation |
C/2013 U1 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-11-18T17:23:35.376000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:41Z |
| Obs used |
137 |
| NEO |
- |
| M1 |
13.900 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-10-31.0000000 |
| e |
0.79716890 |
| q (au) |
2.418807 |
| a (au) |
11.925225 |
| i (deg) |
23.941661 |
| Ω (om, deg) |
211.251432 |
| ω (w, deg) |
143.142203 |
| M (ma, deg) |
359.551854 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.975 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.975 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-0.998 |
| k |
1.000 |
| δ90 |
9.999 |
| 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) |
| 2026-06-01 00:00 |
10:16:57.01 |
-09:03:09.5 |
HIP 50363 |
1.04 |
| 2026-06-01 12:00 |
10:16:58.49 |
-09:02:44.4 |
HIP 50363 |
0.50 |
| 2026-06-02 00:00 |
10:17:00.01 |
-09:02:19.7 |
HIP 50363 |
0.20 |
| 2026-06-02 12:00 |
10:17:01.58 |
-09:01:55.3 |
HIP 50363 |
0.67 |
| 2026-06-03 00:00 |
10:17:03.20 |
-09:01:31.2 |
HIP 50363 |
1.22 |
| 2026-06-03 12:00 |
10:17:04.86 |
-09:01:07.4 |
HIP 50363 |
1.79 |
| 2026-06-04 00:00 |
10:17:06.57 |
-09:00:44.0 |
HIP 50363 |
2.36 |
| 2026-06-04 12:00 |
10:17:08.32 |
-09:00:20.9 |
HIP 50363 |
2.93 |
| 2026-06-05 00:00 |
10:17:10.13 |
-08:59:58.1 |
HIP 50363 |
3.52 |
| 2026-06-05 12:00 |
10:17:11.97 |
-08:59:35.6 |
HIP 50363 |
4.10 |
| 2026-06-06 00:00 |
10:17:13.87 |
-08:59:13.5 |
HIP 50363 |
4.69 |
| 2026-06-06 12:00 |
10:17:15.80 |
-08:58:51.7 |
HIP 50363 |
5.29 |
| 2026-06-07 00:00 |
10:17:17.79 |
-08:58:30.2 |
HIP 50363 |
5.89 |
| 2026-06-07 12:00 |
10:17:19.82 |
-08:58:09.0 |
HIP 50363 |
6.50 |
| 2026-06-08 00:00 |
10:17:21.89 |
-08:57:48.2 |
HIP 50363 |
7.11 |
| 2026-06-08 12:00 |
10:17:24.01 |
-08:57:27.7 |
HIP 50352 |
7.50 |
| 2026-06-09 00:00 |
10:17:26.18 |
-08:57:07.6 |
HIP 50352 |
7.90 |
| 2026-06-09 12:00 |
10:17:28.39 |
-08:56:47.8 |
HIP 50352 |
8.35 |
| 2026-06-10 00:00 |
10:17:30.64 |
-08:56:28.3 |
HIP 50352 |
8.83 |
| 2026-06-10 12:00 |
10:17:32.94 |
-08:56:09.2 |
HIP 50352 |
9.34 |
| 2026-06-11 00:00 |
10:17:35.28 |
-08:55:50.4 |
HIP 50352 |
9.88 |
| 2026-06-11 12:00 |
10:17:37.67 |
-08:55:31.9 |
HIP 50352 |
10.45 |
| 2026-06-12 00:00 |
10:17:40.10 |
-08:55:13.8 |
HIP 50352 |
11.04 |
| 2026-06-12 12:00 |
10:17:42.58 |
-08:54:56.0 |
HIP 50352 |
11.65 |
| 2026-06-13 00:00 |
10:17:45.10 |
-08:54:38.6 |
HIP 50352 |
12.27 |
| 2026-06-13 12:00 |
10:17:47.66 |
-08:54:21.5 |
HIP 50352 |
12.91 |
| 2026-06-14 00:00 |
10:17:50.27 |
-08:54:04.8 |
HIP 50352 |
13.57 |
| 2026-06-14 12:00 |
10:17:52.92 |
-08:53:48.4 |
HIP 50352 |
14.24 |
| 2026-06-15 00:00 |
10:17:55.61 |
-08:53:32.4 |
HIP 50352 |
14.93 |
| 2026-06-15 12:00 |
10:17:58.35 |
-08:53:16.7 |
HIP 50352 |
15.63 |
| 2026-06-16 00:00 |
10:18:01.12 |
-08:53:01.4 |
HIP 50352 |
16.34 |
| 2026-06-16 12:00 |
10:18:03.94 |
-08:52:46.4 |
HIP 50498 |
16.23 |
| 2026-06-17 00:00 |
10:18:06.81 |
-08:52:31.8 |
HIP 50498 |
15.62 |
| 2026-06-17 12:00 |
10:18:09.71 |
-08:52:17.5 |
HIP 50498 |
15.03 |
| 2026-06-18 00:00 |
10:18:12.66 |
-08:52:03.5 |
HIP 50498 |
14.45 |
| 2026-06-18 12:00 |
10:18:15.65 |
-08:51:50.0 |
HIP 50498 |
13.89 |
| 2026-06-19 00:00 |
10:18:18.67 |
-08:51:36.7 |
HIP 50498 |
13.35 |
| 2026-06-19 12:00 |
10:18:21.74 |
-08:51:23.8 |
HIP 50498 |
12.84 |
| 2026-06-20 00:00 |
10:18:24.85 |
-08:51:11.3 |
HIP 50498 |
12.36 |
| 2026-06-20 12:00 |
10:18:28.00 |
-08:50:59.1 |
HIP 50498 |
11.92 |
| 2026-06-21 00:00 |
10:18:31.20 |
-08:50:47.3 |
HIP 50498 |
11.52 |
| 2026-06-21 12:00 |
10:18:34.43 |
-08:50:35.9 |
HIP 50498 |
11.17 |
| 2026-06-22 00:00 |
10:18:37.70 |
-08:50:24.7 |
HIP 50498 |
10.87 |