C/2013 U1 (Catalina)
| 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 |
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) |
| 2026-02-03 00:00 |
10:29:52.95 |
-11:29:25.2 |
HIP 51575 |
31.72 |
| 2026-02-03 12:00 |
10:29:47.84 |
-11:29:08.0 |
HIP 51575 |
32.93 |
| 2026-02-04 00:00 |
10:29:42.71 |
-11:28:50.4 |
HIP 51575 |
34.15 |
| 2026-02-04 12:00 |
10:29:37.55 |
-11:28:32.5 |
HIP 51575 |
35.38 |
| 2026-02-05 00:00 |
10:29:32.38 |
-11:28:14.1 |
HIP 51575 |
36.62 |
| 2026-02-05 12:00 |
10:29:27.18 |
-11:27:55.3 |
HIP 51575 |
37.86 |
| 2026-02-06 00:00 |
10:29:21.97 |
-11:27:36.1 |
HIP 51575 |
39.12 |
| 2026-02-06 12:00 |
10:29:16.73 |
-11:27:16.5 |
HIP 51575 |
40.39 |
| 2026-02-07 00:00 |
10:29:11.48 |
-11:26:56.5 |
HIP 51575 |
41.66 |
| 2026-02-07 12:00 |
10:29:06.21 |
-11:26:36.1 |
HIP 51575 |
42.94 |
| 2026-02-08 00:00 |
10:29:00.92 |
-11:26:15.3 |
HIP 51452 |
44.00 |
| 2026-02-08 12:00 |
10:28:55.61 |
-11:25:54.1 |
HIP 51452 |
44.38 |
| 2026-02-09 00:00 |
10:28:50.29 |
-11:25:32.5 |
HIP 51452 |
44.80 |
| 2026-02-09 12:00 |
10:28:44.95 |
-11:25:10.5 |
HIP 51452 |
45.25 |
| 2026-02-10 00:00 |
10:28:39.60 |
-11:24:48.2 |
HIP 51452 |
45.74 |
| 2026-02-10 12:00 |
10:28:34.23 |
-11:24:25.4 |
HIP 51452 |
46.25 |
| 2026-02-11 00:00 |
10:28:28.84 |
-11:24:02.3 |
HIP 51452 |
46.80 |
| 2026-02-11 12:00 |
10:28:23.44 |
-11:23:38.7 |
HIP 51452 |
47.38 |
| 2026-02-12 00:00 |
10:28:18.03 |
-11:23:14.8 |
HIP 51452 |
47.99 |
| 2026-02-12 12:00 |
10:28:12.61 |
-11:22:50.5 |
HIP 51452 |
48.63 |
| 2026-02-13 00:00 |
10:28:07.17 |
-11:22:25.9 |
HIP 51098 |
49.24 |
| 2026-02-13 12:00 |
10:28:01.72 |
-11:22:00.8 |
HIP 51098 |
48.93 |
| 2026-02-14 00:00 |
10:27:56.26 |
-11:21:35.4 |
HIP 51098 |
48.66 |
| 2026-02-14 12:00 |
10:27:50.78 |
-11:21:09.6 |
HIP 51098 |
48.43 |
| 2026-02-15 00:00 |
10:27:45.30 |
-11:20:43.4 |
HIP 51098 |
48.25 |
| 2026-02-15 12:00 |
10:27:39.81 |
-11:20:16.9 |
HIP 51098 |
48.12 |
| 2026-02-16 00:00 |
10:27:34.31 |
-11:19:50.0 |
HIP 51098 |
48.03 |
| 2026-02-16 12:00 |
10:27:28.80 |
-11:19:22.8 |
HIP 51098 |
47.99 |
| 2026-02-17 00:00 |
10:27:23.28 |
-11:18:55.1 |
HIP 51098 |
47.99 |
| 2026-02-17 12:00 |
10:27:17.76 |
-11:18:27.2 |
HIP 51098 |
48.04 |
| 2026-02-18 00:00 |
10:27:12.23 |
-11:17:58.8 |
HIP 51098 |
48.14 |
| 2026-02-18 12:00 |
10:27:06.69 |
-11:17:30.2 |
HIP 51098 |
48.29 |
| 2026-02-19 00:00 |
10:27:01.15 |
-11:17:01.1 |
HIP 51098 |
48.49 |
| 2026-02-19 12:00 |
10:26:55.60 |
-11:16:31.8 |
HIP 51098 |
48.73 |
| 2026-02-20 00:00 |
10:26:50.05 |
-11:16:02.0 |
HIP 51098 |
49.02 |
| 2026-02-20 12:00 |
10:26:44.49 |
-11:15:32.0 |
HIP 51098 |
49.36 |
| 2026-02-21 00:00 |
10:26:38.93 |
-11:15:01.6 |
HIP 51098 |
49.74 |
| 2026-02-21 12:00 |
10:26:33.37 |
-11:14:30.8 |
HIP 51098 |
50.16 |
| 2026-02-22 00:00 |
10:26:27.80 |
-11:13:59.8 |
HIP 51098 |
50.63 |
| 2026-02-22 12:00 |
10:26:22.24 |
-11:13:28.4 |
HIP 50850 |
49.77 |
| 2026-02-23 00:00 |
10:26:16.67 |
-11:12:56.7 |
HIP 50850 |
48.45 |
| 2026-02-23 12:00 |
10:26:11.10 |
-11:12:24.7 |
HIP 50850 |
47.14 |
| 2026-02-24 00:00 |
10:26:05.54 |
-11:11:52.3 |
HIP 50850 |
45.84 |