| 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) |
| 2026-03-26 00:00 |
10:20:51.63 |
-10:31:59.1 |
HIP 50643 |
16.60 |
| 2026-03-26 12:00 |
10:20:47.06 |
-10:31:14.0 |
HIP 50643 |
17.10 |
| 2026-03-27 00:00 |
10:20:42.51 |
-10:30:28.9 |
HIP 50643 |
17.69 |
| 2026-03-27 12:00 |
10:20:37.99 |
-10:29:43.7 |
HIP 50643 |
18.36 |
| 2026-03-28 00:00 |
10:20:33.51 |
-10:28:58.4 |
HIP 50643 |
19.11 |
| 2026-03-28 12:00 |
10:20:29.06 |
-10:28:13.0 |
HIP 50643 |
19.91 |
| 2026-03-29 00:00 |
10:20:24.64 |
-10:27:27.6 |
HIP 50643 |
20.77 |
| 2026-03-29 12:00 |
10:20:20.26 |
-10:26:42.1 |
HIP 50643 |
21.68 |
| 2026-03-30 00:00 |
10:20:15.91 |
-10:25:56.5 |
HIP 50643 |
22.63 |
| 2026-03-30 12:00 |
10:20:11.59 |
-10:25:10.9 |
HIP 50643 |
23.61 |
| 2026-03-31 00:00 |
10:20:07.30 |
-10:24:25.3 |
HIP 50643 |
24.62 |
| 2026-03-31 12:00 |
10:20:03.05 |
-10:23:39.5 |
HIP 50643 |
25.65 |
| 2026-04-01 00:00 |
10:19:58.84 |
-10:22:53.8 |
HIP 50643 |
26.70 |
| 2026-04-01 12:00 |
10:19:54.66 |
-10:22:08.0 |
HIP 50532 |
26.78 |
| 2026-04-02 00:00 |
10:19:50.51 |
-10:21:22.2 |
HIP 50532 |
25.71 |
| 2026-04-02 12:00 |
10:19:46.40 |
-10:20:36.3 |
HIP 50532 |
24.66 |
| 2026-04-03 00:00 |
10:19:42.33 |
-10:19:50.4 |
HIP 50532 |
23.63 |
| 2026-04-03 12:00 |
10:19:38.30 |
-10:19:04.5 |
HIP 50532 |
22.64 |
| 2026-04-04 00:00 |
10:19:34.30 |
-10:18:18.6 |
HIP 50532 |
21.66 |
| 2026-04-04 12:00 |
10:19:30.33 |
-10:17:32.6 |
HIP 50532 |
20.73 |
| 2026-04-05 00:00 |
10:19:26.41 |
-10:16:46.6 |
HIP 50532 |
19.82 |
| 2026-04-05 12:00 |
10:19:22.52 |
-10:16:00.6 |
HIP 50532 |
18.95 |
| 2026-04-06 00:00 |
10:19:18.67 |
-10:15:14.7 |
HIP 50532 |
18.13 |
| 2026-04-06 12:00 |
10:19:14.86 |
-10:14:28.7 |
HIP 50532 |
17.35 |
| 2026-04-07 00:00 |
10:19:11.09 |
-10:13:42.7 |
HIP 50532 |
16.62 |
| 2026-04-07 12:00 |
10:19:07.35 |
-10:12:56.7 |
HIP 50532 |
15.94 |
| 2026-04-08 00:00 |
10:19:03.66 |
-10:12:10.7 |
HIP 50532 |
15.34 |
| 2026-04-08 12:00 |
10:19:00.00 |
-10:11:24.8 |
HIP 50532 |
14.79 |
| 2026-04-09 00:00 |
10:18:56.39 |
-10:10:38.9 |
HIP 50532 |
14.33 |
| 2026-04-09 12:00 |
10:18:52.81 |
-10:09:52.9 |
HIP 50532 |
13.94 |
| 2026-04-10 00:00 |
10:18:49.28 |
-10:09:07.0 |
HIP 50532 |
13.64 |
| 2026-04-10 12:00 |
10:18:45.79 |
-10:08:21.2 |
HIP 50532 |
13.42 |
| 2026-04-11 00:00 |
10:18:42.33 |
-10:07:35.4 |
HIP 50532 |
13.30 |
| 2026-04-11 12:00 |
10:18:38.92 |
-10:06:49.6 |
HIP 50532 |
13.26 |
| 2026-04-12 00:00 |
10:18:35.56 |
-10:06:03.8 |
HIP 50532 |
13.32 |
| 2026-04-12 12:00 |
10:18:32.23 |
-10:05:18.1 |
HIP 50532 |
13.46 |
| 2026-04-13 00:00 |
10:18:28.94 |
-10:04:32.5 |
HIP 50532 |
13.69 |
| 2026-04-13 12:00 |
10:18:25.70 |
-10:03:46.9 |
HIP 50532 |
13.99 |
| 2026-04-14 00:00 |
10:18:22.50 |
-10:03:01.3 |
HIP 50532 |
14.36 |
| 2026-04-14 12:00 |
10:18:19.35 |
-10:02:15.8 |
HIP 50532 |
14.79 |
| 2026-04-15 00:00 |
10:18:16.23 |
-10:01:30.4 |
HIP 50532 |
15.28 |
| 2026-04-15 12:00 |
10:18:13.16 |
-10:00:45.1 |
HIP 50532 |
15.82 |
| 2026-04-16 00:00 |
10:18:10.14 |
-09:59:59.8 |
HIP 50532 |
16.39 |