| Parameter |
Value |
| Designation |
C/2009 K2 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-02-07T11:38:37.547520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:31Z |
| Obs used |
665 |
| NEO |
- |
| M1 |
11.800 |
| K1 |
7.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-08-14.0000000 |
| e |
0.99777882 |
| q (au) |
3.246176 |
| a (au) |
1461.466569 |
| i (deg) |
66.821915 |
| Ω (om, deg) |
123.805511 |
| ω (w, deg) |
147.693496 |
| M (ma, deg) |
359.996869 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.341 + 4.485\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.341 |
| n |
4.485 |
| gf |
1.000 |
| gb |
-0.989 |
| 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) |
| 2026-09-20 00:00 |
05:40:36.20 |
-35:29:40.8 |
HIP 26787 |
16.28 |
| 2026-09-20 12:00 |
05:40:36.22 |
-35:30:23.0 |
HIP 26787 |
15.71 |
| 2026-09-21 00:00 |
05:40:36.20 |
-35:31:05.3 |
HIP 26787 |
15.16 |
| 2026-09-21 12:00 |
05:40:36.15 |
-35:31:47.5 |
HIP 26787 |
14.63 |
| 2026-09-22 00:00 |
05:40:36.06 |
-35:32:29.7 |
HIP 26787 |
14.12 |
| 2026-09-22 12:00 |
05:40:35.93 |
-35:33:11.9 |
HIP 26787 |
13.63 |
| 2026-09-23 00:00 |
05:40:35.76 |
-35:33:54.1 |
HIP 26787 |
13.17 |
| 2026-09-23 12:00 |
05:40:35.56 |
-35:34:36.3 |
HIP 26787 |
12.73 |
| 2026-09-24 00:00 |
05:40:35.32 |
-35:35:18.4 |
HIP 26787 |
12.33 |
| 2026-09-24 12:00 |
05:40:35.05 |
-35:36:00.5 |
HIP 26787 |
11.96 |
| 2026-09-25 00:00 |
05:40:34.73 |
-35:36:42.7 |
HIP 26787 |
11.62 |
| 2026-09-25 12:00 |
05:40:34.38 |
-35:37:24.7 |
HIP 26787 |
11.33 |
| 2026-09-26 00:00 |
05:40:34.00 |
-35:38:06.8 |
HIP 26787 |
11.09 |
| 2026-09-26 12:00 |
05:40:33.57 |
-35:38:48.8 |
HIP 26787 |
10.89 |
| 2026-09-27 00:00 |
05:40:33.11 |
-35:39:30.8 |
HIP 26787 |
10.74 |
| 2026-09-27 12:00 |
05:40:32.61 |
-35:40:12.7 |
HIP 26787 |
10.64 |
| 2026-09-28 00:00 |
05:40:32.08 |
-35:40:54.6 |
HIP 26787 |
10.59 |
| 2026-09-28 12:00 |
05:40:31.51 |
-35:41:36.5 |
HIP 26787 |
10.60 |
| 2026-09-29 00:00 |
05:40:30.90 |
-35:42:18.3 |
HIP 26787 |
10.67 |
| 2026-09-29 12:00 |
05:40:30.26 |
-35:43:00.0 |
HIP 26787 |
10.79 |
| 2026-09-30 00:00 |
05:40:29.57 |
-35:43:41.7 |
HIP 26787 |
10.96 |
| 2026-09-30 12:00 |
05:40:28.86 |
-35:44:23.3 |
HIP 26787 |
11.18 |
| 2026-10-01 00:00 |
05:40:28.10 |
-35:45:04.9 |
HIP 26787 |
11.45 |
| 2026-10-01 12:00 |
05:40:27.31 |
-35:45:46.4 |
HIP 26787 |
11.76 |
| 2026-10-02 00:00 |
05:40:26.48 |
-35:46:27.9 |
HIP 26787 |
12.11 |
| 2026-10-02 12:00 |
05:40:25.61 |
-35:47:09.2 |
HIP 26787 |
12.50 |
| 2026-10-03 00:00 |
05:40:24.71 |
-35:47:50.5 |
HIP 26787 |
12.92 |
| 2026-10-03 12:00 |
05:40:23.77 |
-35:48:31.7 |
HIP 26787 |
13.37 |
| 2026-10-04 00:00 |
05:40:22.79 |
-35:49:12.8 |
HIP 26787 |
13.85 |
| 2026-10-04 12:00 |
05:40:21.78 |
-35:49:53.9 |
HIP 26787 |
14.36 |
| 2026-10-05 00:00 |
05:40:20.73 |
-35:50:34.8 |
HIP 26787 |
14.89 |
| 2026-10-05 12:00 |
05:40:19.65 |
-35:51:15.7 |
HIP 26787 |
15.44 |
| 2026-10-06 00:00 |
05:40:18.52 |
-35:51:56.5 |
HIP 26787 |
16.00 |
| 2026-10-06 12:00 |
05:40:17.36 |
-35:52:37.1 |
HIP 26787 |
16.59 |
| 2026-10-07 00:00 |
05:40:16.17 |
-35:53:17.7 |
HIP 26787 |
17.19 |
| 2026-10-07 12:00 |
05:40:14.93 |
-35:53:58.1 |
HIP 26787 |
17.80 |
| 2026-10-08 00:00 |
05:40:13.67 |
-35:54:38.5 |
HIP 26787 |
18.42 |
| 2026-10-08 12:00 |
05:40:12.36 |
-35:55:18.7 |
HIP 26787 |
19.06 |
| 2026-10-09 00:00 |
05:40:11.02 |
-35:55:58.8 |
HIP 26787 |
19.70 |
| 2026-10-09 12:00 |
05:40:09.64 |
-35:56:38.8 |
HIP 26787 |
20.36 |
| 2026-10-10 00:00 |
05:40:08.23 |
-35:57:18.6 |
HIP 26787 |
21.02 |
| 2026-10-10 12:00 |
05:40:06.78 |
-35:57:58.3 |
HIP 26787 |
21.69 |
| 2026-10-11 00:00 |
05:40:05.29 |
-35:58:37.9 |
HIP 26787 |
22.37 |