| Parameter |
Value |
| Designation |
C/2009 O2 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-03-24T09:57:09.682560Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:31Z |
| Obs used |
281 |
| NEO |
- |
| M1 |
12.900 |
| K1 |
7.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-10-31.0000000 |
| e |
0.99749905 |
| q (au) |
0.695547 |
| a (au) |
278.112822 |
| i (deg) |
107.960453 |
| Ω (om, deg) |
310.232085 |
| ω (w, deg) |
133.397136 |
| M (ma, deg) |
359.969311 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.631 + 3.055\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.631 |
| n |
3.055 |
| gf |
0.800 |
| gb |
-0.619 |
| k |
0.800 |
| δ90 |
9.999 |
| 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 |
| 2009-03-10 |
2009-07-30 |
-77.4381 |
+43.845 |
| 2009-07-30 |
2009-12-03 |
+12.4136 |
-6.726 |
| 2009-12-03 |
2010-03-24 |
-7.2272 |
-1.412 |
| 2010-03-26 |
2010-04-16 |
-88.5728 |
-12.010 |
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 |
01:11:49.23 |
-56:11:02.5 |
HIP 5455 |
19.59 |
| 2026-03-26 12:00 |
01:11:54.47 |
-56:10:42.3 |
HIP 5455 |
20.38 |
| 2026-03-27 00:00 |
01:11:59.73 |
-56:10:22.5 |
HIP 5455 |
21.18 |
| 2026-03-27 12:00 |
01:12:04.99 |
-56:10:03.1 |
HIP 5455 |
21.97 |
| 2026-03-28 00:00 |
01:12:10.26 |
-56:09:44.0 |
HIP 5455 |
22.77 |
| 2026-03-28 12:00 |
01:12:15.54 |
-56:09:25.2 |
HIP 5762 |
22.81 |
| 2026-03-29 00:00 |
01:12:20.83 |
-56:09:06.8 |
HIP 5762 |
22.12 |
| 2026-03-29 12:00 |
01:12:26.13 |
-56:08:48.8 |
HIP 5762 |
21.44 |
| 2026-03-30 00:00 |
01:12:31.43 |
-56:08:31.1 |
HIP 5762 |
20.77 |
| 2026-03-30 12:00 |
01:12:36.75 |
-56:08:13.8 |
HIP 5762 |
20.11 |
| 2026-03-31 00:00 |
01:12:42.07 |
-56:07:56.8 |
HIP 5762 |
19.47 |
| 2026-03-31 12:00 |
01:12:47.39 |
-56:07:40.2 |
HIP 5762 |
18.84 |
| 2026-04-01 00:00 |
01:12:52.73 |
-56:07:23.9 |
HIP 5762 |
18.23 |
| 2026-04-01 12:00 |
01:12:58.07 |
-56:07:08.1 |
HIP 5762 |
17.65 |
| 2026-04-02 00:00 |
01:13:03.41 |
-56:06:52.5 |
HIP 5762 |
17.08 |
| 2026-04-02 12:00 |
01:13:08.76 |
-56:06:37.4 |
HIP 5762 |
16.54 |
| 2026-04-03 00:00 |
01:13:14.12 |
-56:06:22.5 |
HIP 5762 |
16.02 |
| 2026-04-03 12:00 |
01:13:19.48 |
-56:06:08.1 |
HIP 5762 |
15.53 |
| 2026-04-04 00:00 |
01:13:24.85 |
-56:05:54.0 |
HIP 5762 |
15.07 |
| 2026-04-04 12:00 |
01:13:30.22 |
-56:05:40.3 |
HIP 5762 |
14.65 |
| 2026-04-05 00:00 |
01:13:35.59 |
-56:05:27.0 |
HIP 5762 |
14.26 |
| 2026-04-05 12:00 |
01:13:40.97 |
-56:05:14.0 |
HIP 5762 |
13.91 |
| 2026-04-06 00:00 |
01:13:46.35 |
-56:05:01.4 |
HIP 5762 |
13.61 |
| 2026-04-06 12:00 |
01:13:51.73 |
-56:04:49.1 |
HIP 5762 |
13.34 |
| 2026-04-07 00:00 |
01:13:57.11 |
-56:04:37.2 |
HIP 5762 |
13.13 |
| 2026-04-07 12:00 |
01:14:02.50 |
-56:04:25.7 |
HIP 5762 |
12.96 |
| 2026-04-08 00:00 |
01:14:07.89 |
-56:04:14.6 |
HIP 5762 |
12.85 |
| 2026-04-08 12:00 |
01:14:13.28 |
-56:04:03.8 |
HIP 5762 |
12.79 |
| 2026-04-09 00:00 |
01:14:18.67 |
-56:03:53.4 |
HIP 5762 |
12.78 |
| 2026-04-09 12:00 |
01:14:24.07 |
-56:03:43.4 |
HIP 5762 |
12.83 |
| 2026-04-10 00:00 |
01:14:29.46 |
-56:03:33.7 |
HIP 5762 |
12.92 |
| 2026-04-10 12:00 |
01:14:34.85 |
-56:03:24.5 |
HIP 5762 |
13.07 |
| 2026-04-11 00:00 |
01:14:40.25 |
-56:03:15.6 |
HIP 5762 |
13.27 |
| 2026-04-11 12:00 |
01:14:45.64 |
-56:03:07.0 |
HIP 5762 |
13.51 |
| 2026-04-12 00:00 |
01:14:51.03 |
-56:02:58.9 |
HIP 5762 |
13.80 |
| 2026-04-12 12:00 |
01:14:56.42 |
-56:02:51.1 |
HIP 5762 |
14.12 |
| 2026-04-13 00:00 |
01:15:01.81 |
-56:02:43.7 |
HIP 5762 |
14.49 |
| 2026-04-13 12:00 |
01:15:07.19 |
-56:02:36.7 |
HIP 5762 |
14.89 |
| 2026-04-14 00:00 |
01:15:12.58 |
-56:02:30.1 |
HIP 5762 |
15.32 |
| 2026-04-14 12:00 |
01:15:17.96 |
-56:02:23.8 |
HIP 5762 |
15.78 |
| 2026-04-15 00:00 |
01:15:23.34 |
-56:02:17.9 |
HIP 5762 |
16.27 |
| 2026-04-15 12:00 |
01:15:28.71 |
-56:02:12.4 |
HIP 5762 |
16.78 |
| 2026-04-16 00:00 |
01:15:34.08 |
-56:02:07.3 |
HIP 5762 |
17.31 |