| 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 |
-0.595 |
| 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 |
05:22:27.07 |
-35:29:35.6 |
HIP 25091 |
11.88 |
| 2026-03-26 12:00 |
05:22:28.33 |
-35:28:47.4 |
HIP 25091 |
11.13 |
| 2026-03-27 00:00 |
05:22:29.63 |
-35:27:59.4 |
HIP 25091 |
10.39 |
| 2026-03-27 12:00 |
05:22:30.96 |
-35:27:11.4 |
HIP 25091 |
9.68 |
| 2026-03-28 00:00 |
05:22:32.33 |
-35:26:23.6 |
HIP 25091 |
9.00 |
| 2026-03-28 12:00 |
05:22:33.73 |
-35:25:35.9 |
HIP 25091 |
8.35 |
| 2026-03-29 00:00 |
05:22:35.17 |
-35:24:48.3 |
HIP 25091 |
7.74 |
| 2026-03-29 12:00 |
05:22:36.64 |
-35:24:00.8 |
HIP 25091 |
7.19 |
| 2026-03-30 00:00 |
05:22:38.15 |
-35:23:13.4 |
HIP 25091 |
6.70 |
| 2026-03-30 12:00 |
05:22:39.69 |
-35:22:26.1 |
HIP 25091 |
6.30 |
| 2026-03-31 00:00 |
05:22:41.27 |
-35:21:39.0 |
HIP 25091 |
6.00 |
| 2026-03-31 12:00 |
05:22:42.88 |
-35:20:52.0 |
HIP 25091 |
5.82 |
| 2026-04-01 00:00 |
05:22:44.53 |
-35:20:05.1 |
HIP 25091 |
5.76 |
| 2026-04-01 12:00 |
05:22:46.21 |
-35:19:18.3 |
HIP 25091 |
5.83 |
| 2026-04-02 00:00 |
05:22:47.92 |
-35:18:31.7 |
HIP 25091 |
6.04 |
| 2026-04-02 12:00 |
05:22:49.67 |
-35:17:45.3 |
HIP 25091 |
6.36 |
| 2026-04-03 00:00 |
05:22:51.45 |
-35:16:58.9 |
HIP 25091 |
6.77 |
| 2026-04-03 12:00 |
05:22:53.27 |
-35:16:12.7 |
HIP 25091 |
7.28 |
| 2026-04-04 00:00 |
05:22:55.12 |
-35:15:26.7 |
HIP 25091 |
7.84 |
| 2026-04-04 12:00 |
05:22:57.00 |
-35:14:40.8 |
HIP 25091 |
8.47 |
| 2026-04-05 00:00 |
05:22:58.92 |
-35:13:55.1 |
HIP 25091 |
9.13 |
| 2026-04-05 12:00 |
05:23:00.87 |
-35:13:09.5 |
HIP 25091 |
9.83 |
| 2026-04-06 00:00 |
05:23:02.85 |
-35:12:24.0 |
HIP 25091 |
10.56 |
| 2026-04-06 12:00 |
05:23:04.86 |
-35:11:38.8 |
HIP 25091 |
11.31 |
| 2026-04-07 00:00 |
05:23:06.91 |
-35:10:53.7 |
HIP 25091 |
12.08 |
| 2026-04-07 12:00 |
05:23:08.99 |
-35:10:08.7 |
HIP 25091 |
12.86 |
| 2026-04-08 00:00 |
05:23:11.10 |
-35:09:23.9 |
HIP 25265 |
12.58 |
| 2026-04-08 12:00 |
05:23:13.24 |
-35:08:39.3 |
HIP 25265 |
12.15 |
| 2026-04-09 00:00 |
05:23:15.42 |
-35:07:54.9 |
HIP 25265 |
11.76 |
| 2026-04-09 12:00 |
05:23:17.63 |
-35:07:10.6 |
HIP 25265 |
11.41 |
| 2026-04-10 00:00 |
05:23:19.87 |
-35:06:26.6 |
HIP 25265 |
11.11 |
| 2026-04-10 12:00 |
05:23:22.14 |
-35:05:42.7 |
HIP 25265 |
10.87 |
| 2026-04-11 00:00 |
05:23:24.44 |
-35:04:59.0 |
HIP 25265 |
10.68 |
| 2026-04-11 12:00 |
05:23:26.78 |
-35:04:15.4 |
HIP 25265 |
10.56 |
| 2026-04-12 00:00 |
05:23:29.14 |
-35:03:32.1 |
HIP 25265 |
10.50 |
| 2026-04-12 12:00 |
05:23:31.54 |
-35:02:49.0 |
HIP 25265 |
10.50 |
| 2026-04-13 00:00 |
05:23:33.96 |
-35:02:06.0 |
HIP 25265 |
10.57 |
| 2026-04-13 12:00 |
05:23:36.42 |
-35:01:23.3 |
HIP 25265 |
10.70 |
| 2026-04-14 00:00 |
05:23:38.90 |
-35:00:40.7 |
HIP 25265 |
10.89 |
| 2026-04-14 12:00 |
05:23:41.42 |
-34:59:58.4 |
HIP 25265 |
11.14 |
| 2026-04-15 00:00 |
05:23:43.97 |
-34:59:16.2 |
HIP 25265 |
11.45 |
| 2026-04-15 12:00 |
05:23:46.54 |
-34:58:34.3 |
HIP 25265 |
11.81 |
| 2026-04-16 00:00 |
05:23:49.15 |
-34:57:52.6 |
HIP 25265 |
12.21 |