C/2009 Y1 (Catalina)
| Parameter |
Value |
| Designation |
C/2009 Y1 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2011-01-28T21:38:30.526080Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:38Z |
| Obs used |
1677 |
| NEO |
- |
| M1 |
6.400 |
| K1 |
14.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-01-30.0000000 |
| e |
0.99328974 |
| q (au) |
2.520495 |
| a (au) |
375.617800 |
| i (deg) |
107.316562 |
| Ω (om, deg) |
160.277046 |
| ω (w, deg) |
127.391328 |
| M (ma, deg) |
0.000149 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.112 + 5.549\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.112 |
| n |
5.549 |
| gf |
0.993 |
| gb |
-0.619 |
| k |
0.800 |
| δ90 |
9.447 |
| 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 |
| 2009-12-17 |
2010-03-31 |
-6.0629 |
+4.073 |
| 2010-03-31 |
2010-08-16 |
+4.8305 |
-2.623 |
| 2010-08-16 |
2011-01-28 |
-4.4879 |
+1.803 |
| 2011-01-29 |
2011-07-12 |
+1.5193 |
-0.976 |
| 2011-07-12 |
2011-12-23 |
-8.7897 |
+4.469 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
09:26:25.74 |
-77:57:27.8 |
HIP 46046 |
10.23 |
| 2026-02-03 12:00 |
09:26:08.97 |
-77:57:30.1 |
HIP 46046 |
9.45 |
| 2026-02-04 00:00 |
09:25:52.19 |
-77:57:31.9 |
HIP 46046 |
8.67 |
| 2026-02-04 12:00 |
09:25:35.39 |
-77:57:33.1 |
HIP 46046 |
7.92 |
| 2026-02-05 00:00 |
09:25:18.59 |
-77:57:33.7 |
HIP 46046 |
7.18 |
| 2026-02-05 12:00 |
09:25:01.77 |
-77:57:33.8 |
HIP 46046 |
6.48 |
| 2026-02-06 00:00 |
09:24:44.95 |
-77:57:33.4 |
HIP 46046 |
5.82 |
| 2026-02-06 12:00 |
09:24:28.11 |
-77:57:32.3 |
HIP 46046 |
5.21 |
| 2026-02-07 00:00 |
09:24:11.28 |
-77:57:30.8 |
HIP 46046 |
4.69 |
| 2026-02-07 12:00 |
09:23:54.44 |
-77:57:28.6 |
HIP 46046 |
4.27 |
| 2026-02-08 00:00 |
09:23:37.61 |
-77:57:25.9 |
HIP 46046 |
4.00 |
| 2026-02-08 12:00 |
09:23:20.77 |
-77:57:22.7 |
HIP 46046 |
3.90 |
| 2026-02-09 00:00 |
09:23:03.94 |
-77:57:18.9 |
HIP 46046 |
3.99 |
| 2026-02-09 12:00 |
09:22:47.12 |
-77:57:14.5 |
HIP 46046 |
4.26 |
| 2026-02-10 00:00 |
09:22:30.30 |
-77:57:09.6 |
HIP 46046 |
4.68 |
| 2026-02-10 12:00 |
09:22:13.49 |
-77:57:04.1 |
HIP 46046 |
5.20 |
| 2026-02-11 00:00 |
09:21:56.70 |
-77:56:58.0 |
HIP 46046 |
5.81 |
| 2026-02-11 12:00 |
09:21:39.91 |
-77:56:51.4 |
HIP 46046 |
6.47 |
| 2026-02-12 00:00 |
09:21:23.15 |
-77:56:44.3 |
HIP 46046 |
7.18 |
| 2026-02-12 12:00 |
09:21:06.40 |
-77:56:36.6 |
HIP 46046 |
7.92 |
| 2026-02-13 00:00 |
09:20:49.67 |
-77:56:28.3 |
HIP 46046 |
8.69 |
| 2026-02-13 12:00 |
09:20:32.96 |
-77:56:19.5 |
HIP 46046 |
9.47 |
| 2026-02-14 00:00 |
09:20:16.27 |
-77:56:10.1 |
HIP 46046 |
10.26 |
| 2026-02-14 12:00 |
09:19:59.61 |
-77:56:00.1 |
HIP 46046 |
11.07 |
| 2026-02-15 00:00 |
09:19:42.98 |
-77:55:49.6 |
HIP 46046 |
11.88 |
| 2026-02-15 12:00 |
09:19:26.38 |
-77:55:38.6 |
HIP 46046 |
12.71 |
| 2026-02-16 00:00 |
09:19:09.80 |
-77:55:27.0 |
HIP 46046 |
13.54 |
| 2026-02-16 12:00 |
09:18:53.27 |
-77:55:14.8 |
HIP 46046 |
14.37 |
| 2026-02-17 00:00 |
09:18:36.76 |
-77:55:02.1 |
HIP 46046 |
15.21 |
| 2026-02-17 12:00 |
09:18:20.29 |
-77:54:48.8 |
HIP 46046 |
16.05 |
| 2026-02-18 00:00 |
09:18:03.87 |
-77:54:35.0 |
HIP 45734 |
16.53 |
| 2026-02-18 12:00 |
09:17:47.48 |
-77:54:20.7 |
HIP 45734 |
16.55 |
| 2026-02-19 00:00 |
09:17:31.14 |
-77:54:05.8 |
HIP 45734 |
16.61 |
| 2026-02-19 12:00 |
09:17:14.84 |
-77:53:50.3 |
HIP 45734 |
16.71 |
| 2026-02-20 00:00 |
09:16:58.58 |
-77:53:34.3 |
HIP 45734 |
16.85 |
| 2026-02-20 12:00 |
09:16:42.38 |
-77:53:17.8 |
HIP 45734 |
17.02 |
| 2026-02-21 00:00 |
09:16:26.23 |
-77:53:00.7 |
HIP 45734 |
17.23 |
| 2026-02-21 12:00 |
09:16:10.12 |
-77:52:43.1 |
HIP 45734 |
17.48 |
| 2026-02-22 00:00 |
09:15:54.08 |
-77:52:24.9 |
HIP 45734 |
17.76 |
| 2026-02-22 12:00 |
09:15:38.09 |
-77:52:06.2 |
HIP 45734 |
18.07 |
| 2026-02-23 00:00 |
09:15:22.15 |
-77:51:47.0 |
HIP 45734 |
18.42 |
| 2026-02-23 12:00 |
09:15:06.28 |
-77:51:27.3 |
HIP 45734 |
18.79 |
| 2026-02-24 00:00 |
09:14:50.47 |
-77:51:07.0 |
HIP 45734 |
19.19 |