| Parameter |
Value |
| Designation |
C/2013 US10 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-11-15T17:19:09.851520Z |
| Orbit solution date (soln_date, UTC) |
2026-03-07T14:42:53Z |
| Obs used |
4397 |
| NEO |
- |
| M1 |
8.500 |
| K1 |
6.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-11-23.0000000 |
| e |
1.00028014 |
| q (au) |
0.822969 |
| a (au) |
-2937.712795 |
| i (deg) |
148.878297 |
| Ω (om, deg) |
186.144580 |
| ω (w, deg) |
340.358754 |
| M (ma, deg) |
0.000045 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.879 + 3.465\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.879 |
| n |
3.465 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
0.800 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2013-11-16 |
2014-09-02 |
+6.3490 |
-5.168 |
| 2014-09-02 |
2015-05-09 |
-1.8469 |
+1.075 |
| 2015-05-09 |
2015-07-22 |
+1.9657 |
-0.856 |
| 2015-07-22 |
2015-09-04 |
+7.2007 |
-2.686 |
| 2015-09-04 |
2015-10-16 |
-7.7697 |
+0.128 |
| 2015-11-22 |
2016-09-01 |
+1.0099 |
+0.081 |
| 2016-09-01 |
2017-10-24 |
-1.4000 |
+1.815 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
02:15:31.15 |
+33:32:29.1 |
HIP 10559 |
12.14 |
| 2026-06-01 12:00 |
02:15:34.99 |
+33:32:55.8 |
HIP 10559 |
12.23 |
| 2026-06-02 00:00 |
02:15:38.81 |
+33:33:22.5 |
HIP 10559 |
12.39 |
| 2026-06-02 12:00 |
02:15:42.61 |
+33:33:49.3 |
HIP 10559 |
12.61 |
| 2026-06-03 00:00 |
02:15:46.39 |
+33:34:16.2 |
HIP 10559 |
12.90 |
| 2026-06-03 12:00 |
02:15:50.14 |
+33:34:43.1 |
HIP 10559 |
13.24 |
| 2026-06-04 00:00 |
02:15:53.87 |
+33:35:10.0 |
HIP 10559 |
13.64 |
| 2026-06-04 12:00 |
02:15:57.57 |
+33:35:37.0 |
HIP 10559 |
14.08 |
| 2026-06-05 00:00 |
02:16:01.26 |
+33:36:04.1 |
HIP 10559 |
14.57 |
| 2026-06-05 12:00 |
02:16:04.91 |
+33:36:31.1 |
HIP 10559 |
15.09 |
| 2026-06-06 00:00 |
02:16:08.55 |
+33:36:58.3 |
HIP 10559 |
15.64 |
| 2026-06-06 12:00 |
02:16:12.16 |
+33:37:25.4 |
HIP 10559 |
16.23 |
| 2026-06-07 00:00 |
02:16:15.74 |
+33:37:52.6 |
HIP 10559 |
16.83 |
| 2026-06-07 12:00 |
02:16:19.30 |
+33:38:19.9 |
HIP 10684 |
16.72 |
| 2026-06-08 00:00 |
02:16:22.84 |
+33:38:47.1 |
HIP 10684 |
15.85 |
| 2026-06-08 12:00 |
02:16:26.35 |
+33:39:14.4 |
HIP 10684 |
14.99 |
| 2026-06-09 00:00 |
02:16:29.83 |
+33:39:41.7 |
HIP 10684 |
14.14 |
| 2026-06-09 12:00 |
02:16:33.29 |
+33:40:09.1 |
HIP 10684 |
13.29 |
| 2026-06-10 00:00 |
02:16:36.72 |
+33:40:36.5 |
HIP 10684 |
12.45 |
| 2026-06-10 12:00 |
02:16:40.12 |
+33:41:03.9 |
HIP 10684 |
11.61 |
| 2026-06-11 00:00 |
02:16:43.50 |
+33:41:31.3 |
HIP 10684 |
10.78 |
| 2026-06-11 12:00 |
02:16:46.85 |
+33:41:58.8 |
HIP 10684 |
9.95 |
| 2026-06-12 00:00 |
02:16:50.17 |
+33:42:26.2 |
HIP 10684 |
9.13 |
| 2026-06-12 12:00 |
02:16:53.47 |
+33:42:53.7 |
HIP 10684 |
8.32 |
| 2026-06-13 00:00 |
02:16:56.74 |
+33:43:21.2 |
HIP 10684 |
7.51 |
| 2026-06-13 12:00 |
02:16:59.98 |
+33:43:48.7 |
HIP 10684 |
6.71 |
| 2026-06-14 00:00 |
02:17:03.19 |
+33:44:16.3 |
HIP 10684 |
5.93 |
| 2026-06-14 12:00 |
02:17:06.37 |
+33:44:43.8 |
HIP 10684 |
5.16 |
| 2026-06-15 00:00 |
02:17:09.53 |
+33:45:11.3 |
HIP 10684 |
4.40 |
| 2026-06-15 12:00 |
02:17:12.65 |
+33:45:38.9 |
HIP 10684 |
3.67 |
| 2026-06-16 00:00 |
02:17:15.74 |
+33:46:06.4 |
HIP 10684 |
2.98 |
| 2026-06-16 12:00 |
02:17:18.81 |
+33:46:34.0 |
HIP 10684 |
2.36 |
| 2026-06-17 00:00 |
02:17:21.85 |
+33:47:01.5 |
HIP 10684 |
1.87 |
| 2026-06-17 12:00 |
02:17:24.85 |
+33:47:29.1 |
HIP 10684 |
1.63 |
| 2026-06-18 00:00 |
02:17:27.82 |
+33:47:56.6 |
HIP 10684 |
1.75 |
| 2026-06-18 12:00 |
02:17:30.77 |
+33:48:24.1 |
HIP 10684 |
2.15 |
| 2026-06-19 00:00 |
02:17:33.68 |
+33:48:51.7 |
HIP 10684 |
2.71 |
| 2026-06-19 12:00 |
02:17:36.56 |
+33:49:19.2 |
HIP 10684 |
3.35 |
| 2026-06-20 00:00 |
02:17:39.41 |
+33:49:46.7 |
HIP 10684 |
4.02 |
| 2026-06-20 12:00 |
02:17:42.23 |
+33:50:14.2 |
HIP 10684 |
4.71 |
| 2026-06-21 00:00 |
02:17:45.02 |
+33:50:41.6 |
HIP 10684 |
5.42 |
| 2026-06-21 12:00 |
02:17:47.78 |
+33:51:09.1 |
HIP 10670 |
6.02 |
| 2026-06-22 00:00 |
02:17:50.50 |
+33:51:36.5 |
HIP 10670 |
6.62 |