| 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) |
| 2026-07-29 00:00 |
05:37:22.08 |
-34:25:38.4 |
HIP 26466 |
16.63 |
| 2026-07-29 12:00 |
05:37:25.43 |
-34:26:03.9 |
HIP 26466 |
16.01 |
| 2026-07-30 00:00 |
05:37:28.76 |
-34:26:29.6 |
HIP 26466 |
15.41 |
| 2026-07-30 12:00 |
05:37:32.06 |
-34:26:55.7 |
HIP 26466 |
14.83 |
| 2026-07-31 00:00 |
05:37:35.34 |
-34:27:22.0 |
HIP 26466 |
14.26 |
| 2026-07-31 12:00 |
05:37:38.59 |
-34:27:48.5 |
HIP 26466 |
13.71 |
| 2026-08-01 00:00 |
05:37:41.82 |
-34:28:15.4 |
HIP 26466 |
13.19 |
| 2026-08-01 12:00 |
05:37:45.03 |
-34:28:42.5 |
HIP 26466 |
12.69 |
| 2026-08-02 00:00 |
05:37:48.22 |
-34:29:09.9 |
HIP 26466 |
12.22 |
| 2026-08-02 12:00 |
05:37:51.38 |
-34:29:37.6 |
HIP 26466 |
11.77 |
| 2026-08-03 00:00 |
05:37:54.52 |
-34:30:05.5 |
HIP 26466 |
11.37 |
| 2026-08-03 12:00 |
05:37:57.63 |
-34:30:33.8 |
HIP 26466 |
11.00 |
| 2026-08-04 00:00 |
05:38:00.72 |
-34:31:02.2 |
HIP 26466 |
10.67 |
| 2026-08-04 12:00 |
05:38:03.79 |
-34:31:30.9 |
HIP 26466 |
10.38 |
| 2026-08-05 00:00 |
05:38:06.82 |
-34:32:00.0 |
HIP 26466 |
10.14 |
| 2026-08-05 12:00 |
05:38:09.84 |
-34:32:29.2 |
HIP 26466 |
9.96 |
| 2026-08-06 00:00 |
05:38:12.83 |
-34:32:58.7 |
HIP 26466 |
9.82 |
| 2026-08-06 12:00 |
05:38:15.79 |
-34:33:28.5 |
HIP 26466 |
9.75 |
| 2026-08-07 00:00 |
05:38:18.73 |
-34:33:58.5 |
HIP 26466 |
9.73 |
| 2026-08-07 12:00 |
05:38:21.64 |
-34:34:28.7 |
HIP 26466 |
9.76 |
| 2026-08-08 00:00 |
05:38:24.52 |
-34:34:59.3 |
HIP 26466 |
9.85 |
| 2026-08-08 12:00 |
05:38:27.38 |
-34:35:30.0 |
HIP 26466 |
10.00 |
| 2026-08-09 00:00 |
05:38:30.22 |
-34:36:01.0 |
HIP 26466 |
10.19 |
| 2026-08-09 12:00 |
05:38:33.02 |
-34:36:32.3 |
HIP 26466 |
10.43 |
| 2026-08-10 00:00 |
05:38:35.80 |
-34:37:03.8 |
HIP 26466 |
10.72 |
| 2026-08-10 12:00 |
05:38:38.55 |
-34:37:35.5 |
HIP 26466 |
11.05 |
| 2026-08-11 00:00 |
05:38:41.27 |
-34:38:07.5 |
HIP 26466 |
11.41 |
| 2026-08-11 12:00 |
05:38:43.97 |
-34:38:39.7 |
HIP 26466 |
11.81 |
| 2026-08-12 00:00 |
05:38:46.64 |
-34:39:12.1 |
HIP 26636 |
11.43 |
| 2026-08-12 12:00 |
05:38:49.28 |
-34:39:44.8 |
HIP 26636 |
10.96 |
| 2026-08-13 00:00 |
05:38:51.89 |
-34:40:17.7 |
HIP 26636 |
10.52 |
| 2026-08-13 12:00 |
05:38:54.47 |
-34:40:50.8 |
HIP 26636 |
10.14 |
| 2026-08-14 00:00 |
05:38:57.02 |
-34:41:24.1 |
HIP 26636 |
9.80 |
| 2026-08-14 12:00 |
05:38:59.55 |
-34:41:57.7 |
HIP 26636 |
9.52 |
| 2026-08-15 00:00 |
05:39:02.05 |
-34:42:31.5 |
HIP 26636 |
9.30 |
| 2026-08-15 12:00 |
05:39:04.51 |
-34:43:05.5 |
HIP 26636 |
9.15 |
| 2026-08-16 00:00 |
05:39:06.95 |
-34:43:39.7 |
HIP 26636 |
9.07 |
| 2026-08-16 12:00 |
05:39:09.36 |
-34:44:14.1 |
HIP 26636 |
9.05 |
| 2026-08-17 00:00 |
05:39:11.73 |
-34:44:48.7 |
HIP 26636 |
9.11 |
| 2026-08-17 12:00 |
05:39:14.08 |
-34:45:23.5 |
HIP 26636 |
9.23 |
| 2026-08-18 00:00 |
05:39:16.40 |
-34:45:58.5 |
HIP 26636 |
9.42 |
| 2026-08-18 12:00 |
05:39:18.69 |
-34:46:33.8 |
HIP 26636 |
9.68 |
| 2026-08-19 00:00 |
05:39:20.94 |
-34:47:09.2 |
HIP 26636 |
9.98 |