| 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) |
| 2026-03-26 00:00 |
02:05:32.33 |
+32:52:03.6 |
HIP 9590 |
40.23 |
| 2026-03-26 12:00 |
02:05:36.51 |
+32:52:08.9 |
HIP 9590 |
40.92 |
| 2026-03-27 00:00 |
02:05:40.70 |
+32:52:14.3 |
HIP 9590 |
41.61 |
| 2026-03-27 12:00 |
02:05:44.92 |
+32:52:20.1 |
HIP 9590 |
42.32 |
| 2026-03-28 00:00 |
02:05:49.15 |
+32:52:26.0 |
HIP 9590 |
43.04 |
| 2026-03-28 12:00 |
02:05:53.40 |
+32:52:32.3 |
HIP 9979 |
43.18 |
| 2026-03-29 00:00 |
02:05:57.67 |
+32:52:38.7 |
HIP 9979 |
42.43 |
| 2026-03-29 12:00 |
02:06:01.95 |
+32:52:45.4 |
HIP 9979 |
41.69 |
| 2026-03-30 00:00 |
02:06:06.25 |
+32:52:52.4 |
HIP 9979 |
40.94 |
| 2026-03-30 12:00 |
02:06:10.56 |
+32:52:59.6 |
HIP 9979 |
40.19 |
| 2026-03-31 00:00 |
02:06:14.89 |
+32:53:07.0 |
HIP 9979 |
39.45 |
| 2026-03-31 12:00 |
02:06:19.23 |
+32:53:14.7 |
HIP 9979 |
38.71 |
| 2026-04-01 00:00 |
02:06:23.59 |
+32:53:22.6 |
HIP 9979 |
37.97 |
| 2026-04-01 12:00 |
02:06:27.96 |
+32:53:30.7 |
HIP 9979 |
37.23 |
| 2026-04-02 00:00 |
02:06:32.35 |
+32:53:39.1 |
HIP 9979 |
36.50 |
| 2026-04-02 12:00 |
02:06:36.75 |
+32:53:47.7 |
HIP 9979 |
35.77 |
| 2026-04-03 00:00 |
02:06:41.17 |
+32:53:56.6 |
HIP 9979 |
35.05 |
| 2026-04-03 12:00 |
02:06:45.60 |
+32:54:05.6 |
HIP 9979 |
34.33 |
| 2026-04-04 00:00 |
02:06:50.04 |
+32:54:14.9 |
HIP 9979 |
33.62 |
| 2026-04-04 12:00 |
02:06:54.50 |
+32:54:24.5 |
HIP 9979 |
32.92 |
| 2026-04-05 00:00 |
02:06:58.96 |
+32:54:34.2 |
HIP 9979 |
32.22 |
| 2026-04-05 12:00 |
02:07:03.44 |
+32:54:44.2 |
HIP 9979 |
31.53 |
| 2026-04-06 00:00 |
02:07:07.93 |
+32:54:54.5 |
HIP 9979 |
30.86 |
| 2026-04-06 12:00 |
02:07:12.44 |
+32:55:04.9 |
HIP 9979 |
30.19 |
| 2026-04-07 00:00 |
02:07:16.95 |
+32:55:15.6 |
HIP 9979 |
29.53 |
| 2026-04-07 12:00 |
02:07:21.48 |
+32:55:26.5 |
HIP 9979 |
28.89 |
| 2026-04-08 00:00 |
02:07:26.01 |
+32:55:37.6 |
HIP 9979 |
28.26 |
| 2026-04-08 12:00 |
02:07:30.56 |
+32:55:49.0 |
HIP 9979 |
27.65 |
| 2026-04-09 00:00 |
02:07:35.12 |
+32:56:00.5 |
HIP 9979 |
27.05 |
| 2026-04-09 12:00 |
02:07:39.68 |
+32:56:12.3 |
HIP 9979 |
26.47 |
| 2026-04-10 00:00 |
02:07:44.26 |
+32:56:24.3 |
HIP 9979 |
25.92 |
| 2026-04-10 12:00 |
02:07:48.84 |
+32:56:36.5 |
HIP 9979 |
25.38 |
| 2026-04-11 00:00 |
02:07:53.44 |
+32:56:49.0 |
HIP 9979 |
24.86 |
| 2026-04-11 12:00 |
02:07:58.04 |
+32:57:01.6 |
HIP 9979 |
24.37 |
| 2026-04-12 00:00 |
02:08:02.65 |
+32:57:14.5 |
HIP 9979 |
23.91 |
| 2026-04-12 12:00 |
02:08:07.27 |
+32:57:27.6 |
HIP 9979 |
23.48 |
| 2026-04-13 00:00 |
02:08:11.90 |
+32:57:40.9 |
HIP 9979 |
23.08 |
| 2026-04-13 12:00 |
02:08:16.53 |
+32:57:54.4 |
HIP 9979 |
22.70 |
| 2026-04-14 00:00 |
02:08:21.17 |
+32:58:08.1 |
HIP 9979 |
22.37 |
| 2026-04-14 12:00 |
02:08:25.82 |
+32:58:22.0 |
HIP 9979 |
22.07 |
| 2026-04-15 00:00 |
02:08:30.48 |
+32:58:36.1 |
HIP 9979 |
21.81 |
| 2026-04-15 12:00 |
02:08:35.14 |
+32:58:50.5 |
HIP 9979 |
21.59 |
| 2026-04-16 00:00 |
02:08:39.80 |
+32:59:05.0 |
HIP 9979 |
21.41 |