| 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) |
| 2026-06-01 00:00 |
01:22:45.96 |
-56:20:46.8 |
HIP 6345 |
16.45 |
| 2026-06-01 12:00 |
01:22:49.51 |
-56:21:15.1 |
HIP 6345 |
17.12 |
| 2026-06-02 00:00 |
01:22:53.04 |
-56:21:43.7 |
HIP 6345 |
17.80 |
| 2026-06-02 12:00 |
01:22:56.53 |
-56:22:12.6 |
HIP 6345 |
18.48 |
| 2026-06-03 00:00 |
01:22:59.99 |
-56:22:41.8 |
HIP 6345 |
19.16 |
| 2026-06-03 12:00 |
01:23:03.41 |
-56:23:11.2 |
HIP 6345 |
19.84 |
| 2026-06-04 00:00 |
01:23:06.80 |
-56:23:41.0 |
HIP 6345 |
20.53 |
| 2026-06-04 12:00 |
01:23:10.16 |
-56:24:11.1 |
HIP 6408 |
20.92 |
| 2026-06-05 00:00 |
01:23:13.48 |
-56:24:41.5 |
HIP 6408 |
20.61 |
| 2026-06-05 12:00 |
01:23:16.76 |
-56:25:12.1 |
HIP 6408 |
20.30 |
| 2026-06-06 00:00 |
01:23:20.01 |
-56:25:43.1 |
HIP 6408 |
20.01 |
| 2026-06-06 12:00 |
01:23:23.23 |
-56:26:14.3 |
HIP 6408 |
19.74 |
| 2026-06-07 00:00 |
01:23:26.40 |
-56:26:45.9 |
HIP 6408 |
19.47 |
| 2026-06-07 12:00 |
01:23:29.55 |
-56:27:17.7 |
HIP 6408 |
19.22 |
| 2026-06-08 00:00 |
01:23:32.65 |
-56:27:49.8 |
HIP 6408 |
18.99 |
| 2026-06-08 12:00 |
01:23:35.72 |
-56:28:22.2 |
HIP 6408 |
18.77 |
| 2026-06-09 00:00 |
01:23:38.75 |
-56:28:54.8 |
HIP 6408 |
18.56 |
| 2026-06-09 12:00 |
01:23:41.75 |
-56:29:27.8 |
HIP 6408 |
18.37 |
| 2026-06-10 00:00 |
01:23:44.70 |
-56:30:01.0 |
HIP 6408 |
18.20 |
| 2026-06-10 12:00 |
01:23:47.62 |
-56:30:34.4 |
HIP 6408 |
18.05 |
| 2026-06-11 00:00 |
01:23:50.50 |
-56:31:08.2 |
HIP 6408 |
17.91 |
| 2026-06-11 12:00 |
01:23:53.35 |
-56:31:42.2 |
HIP 6408 |
17.79 |
| 2026-06-12 00:00 |
01:23:56.15 |
-56:32:16.5 |
HIP 6408 |
17.70 |
| 2026-06-12 12:00 |
01:23:58.92 |
-56:32:51.1 |
HIP 6408 |
17.62 |
| 2026-06-13 00:00 |
01:24:01.64 |
-56:33:25.9 |
HIP 6408 |
17.56 |
| 2026-06-13 12:00 |
01:24:04.33 |
-56:34:01.0 |
HIP 6408 |
17.52 |
| 2026-06-14 00:00 |
01:24:06.98 |
-56:34:36.3 |
HIP 6408 |
17.50 |
| 2026-06-14 12:00 |
01:24:09.58 |
-56:35:11.9 |
HIP 6408 |
17.50 |
| 2026-06-15 00:00 |
01:24:12.15 |
-56:35:47.8 |
HIP 6408 |
17.52 |
| 2026-06-15 12:00 |
01:24:14.68 |
-56:36:23.9 |
HIP 6408 |
17.57 |
| 2026-06-16 00:00 |
01:24:17.17 |
-56:37:00.2 |
HIP 6408 |
17.63 |
| 2026-06-16 12:00 |
01:24:19.61 |
-56:37:36.8 |
HIP 6408 |
17.71 |
| 2026-06-17 00:00 |
01:24:22.02 |
-56:38:13.6 |
HIP 6408 |
17.81 |
| 2026-06-17 12:00 |
01:24:24.38 |
-56:38:50.7 |
HIP 6408 |
17.94 |
| 2026-06-18 00:00 |
01:24:26.70 |
-56:39:28.0 |
HIP 6408 |
18.08 |
| 2026-06-18 12:00 |
01:24:28.98 |
-56:40:05.5 |
HIP 6408 |
18.24 |
| 2026-06-19 00:00 |
01:24:31.22 |
-56:40:43.3 |
HIP 6408 |
18.42 |
| 2026-06-19 12:00 |
01:24:33.41 |
-56:41:21.3 |
HIP 6408 |
18.62 |
| 2026-06-20 00:00 |
01:24:35.57 |
-56:41:59.5 |
HIP 6408 |
18.83 |
| 2026-06-20 12:00 |
01:24:37.68 |
-56:42:38.0 |
HIP 6408 |
19.07 |
| 2026-06-21 00:00 |
01:24:39.75 |
-56:43:16.6 |
HIP 6408 |
19.32 |
| 2026-06-21 12:00 |
01:24:41.78 |
-56:43:55.5 |
HIP 6408 |
19.58 |
| 2026-06-22 00:00 |
01:24:43.76 |
-56:44:34.6 |
HIP 6408 |
19.86 |