C/2008 E1 (Catalina)
| Parameter |
Value |
| Designation |
C/2008 E1 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-08-11T20:28:01.989120Z |
| Orbit solution date (soln_date, UTC) |
2024-04-13T16:42:27Z |
| Obs used |
265 |
| NEO |
- |
| M1 |
6.300 |
| K1 |
12.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-11-20.0000000 |
| e |
0.54811137 |
| q (au) |
4.828912 |
| a (au) |
10.686066 |
| i (deg) |
35.037529 |
| Ω (om, deg) |
189.023580 |
| ω (w, deg) |
269.989090 |
| M (ma, deg) |
2.825635 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.357 + 5.831\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.357 |
| n |
5.831 |
| gf |
1.000 |
| gb |
-0.809 |
| k |
0.800 |
| δ90 |
9.961 |
| 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 |
| 2006-11-19 |
2008-04-04 |
+45.1347 |
-31.077 |
| 2008-09-24 |
2010-04-11 |
-0.2830 |
+0.015 |
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 |
18:36:20.42 |
+10:13:31.3 |
HIP 91156 |
13.65 |
| 2026-02-03 12:00 |
18:36:27.27 |
+10:14:09.5 |
HIP 91156 |
15.10 |
| 2026-02-04 00:00 |
18:36:34.08 |
+10:14:48.2 |
HIP 91156 |
16.62 |
| 2026-02-04 12:00 |
18:36:40.86 |
+10:15:27.2 |
HIP 91156 |
18.19 |
| 2026-02-05 00:00 |
18:36:47.61 |
+10:16:06.5 |
HIP 91156 |
19.79 |
| 2026-02-05 12:00 |
18:36:54.32 |
+10:16:46.3 |
HIP 91156 |
21.42 |
| 2026-02-06 00:00 |
18:37:01.00 |
+10:17:26.4 |
HIP 91156 |
23.08 |
| 2026-02-06 12:00 |
18:37:07.65 |
+10:18:06.9 |
HIP 91156 |
24.74 |
| 2026-02-07 00:00 |
18:37:14.26 |
+10:18:47.8 |
HIP 91156 |
26.42 |
| 2026-02-07 12:00 |
18:37:20.84 |
+10:19:29.0 |
HIP 91156 |
28.11 |
| 2026-02-08 00:00 |
18:37:27.38 |
+10:20:10.6 |
HIP 91156 |
29.80 |
| 2026-02-08 12:00 |
18:37:33.89 |
+10:20:52.6 |
HIP 91156 |
31.49 |
| 2026-02-09 00:00 |
18:37:40.36 |
+10:21:34.9 |
HIP 91156 |
33.19 |
| 2026-02-09 12:00 |
18:37:46.79 |
+10:22:17.6 |
HIP 91156 |
34.88 |
| 2026-02-10 00:00 |
18:37:53.19 |
+10:23:00.6 |
HIP 91447 |
35.54 |
| 2026-02-10 12:00 |
18:37:59.55 |
+10:23:44.0 |
HIP 91447 |
35.47 |
| 2026-02-11 00:00 |
18:38:05.87 |
+10:24:27.8 |
HIP 91447 |
35.49 |
| 2026-02-11 12:00 |
18:38:12.16 |
+10:25:11.8 |
HIP 91447 |
35.60 |
| 2026-02-12 00:00 |
18:38:18.41 |
+10:25:56.3 |
HIP 91447 |
35.80 |
| 2026-02-12 12:00 |
18:38:24.62 |
+10:26:41.1 |
HIP 91447 |
36.09 |
| 2026-02-13 00:00 |
18:38:30.79 |
+10:27:26.2 |
HIP 91451 |
35.30 |
| 2026-02-13 12:00 |
18:38:36.92 |
+10:28:11.7 |
HIP 91451 |
34.21 |
| 2026-02-14 00:00 |
18:38:43.01 |
+10:28:57.5 |
HIP 91451 |
33.17 |
| 2026-02-14 12:00 |
18:38:49.06 |
+10:29:43.6 |
HIP 91451 |
32.18 |
| 2026-02-15 00:00 |
18:38:55.07 |
+10:30:30.1 |
HIP 91451 |
31.24 |
| 2026-02-15 12:00 |
18:39:01.04 |
+10:31:16.8 |
HIP 91451 |
30.37 |
| 2026-02-16 00:00 |
18:39:06.97 |
+10:32:04.0 |
HIP 91451 |
29.55 |
| 2026-02-16 12:00 |
18:39:12.85 |
+10:32:51.4 |
HIP 91451 |
28.80 |
| 2026-02-17 00:00 |
18:39:18.70 |
+10:33:39.1 |
HIP 91451 |
28.12 |
| 2026-02-17 12:00 |
18:39:24.50 |
+10:34:27.2 |
HIP 91451 |
27.51 |
| 2026-02-18 00:00 |
18:39:30.26 |
+10:35:15.6 |
HIP 91451 |
26.99 |
| 2026-02-18 12:00 |
18:39:35.97 |
+10:36:04.3 |
HIP 91451 |
26.54 |
| 2026-02-19 00:00 |
18:39:41.64 |
+10:36:53.3 |
HIP 91586 |
25.71 |
| 2026-02-19 12:00 |
18:39:47.27 |
+10:37:42.6 |
HIP 91586 |
24.25 |
| 2026-02-20 00:00 |
18:39:52.86 |
+10:38:32.2 |
HIP 91586 |
22.81 |
| 2026-02-20 12:00 |
18:39:58.40 |
+10:39:22.0 |
HIP 91586 |
21.40 |
| 2026-02-21 00:00 |
18:40:03.89 |
+10:40:12.2 |
HIP 91586 |
20.02 |
| 2026-02-21 12:00 |
18:40:09.34 |
+10:41:02.7 |
HIP 91586 |
18.67 |
| 2026-02-22 00:00 |
18:40:14.74 |
+10:41:53.4 |
HIP 91586 |
17.35 |
| 2026-02-22 12:00 |
18:40:20.10 |
+10:42:44.5 |
HIP 91586 |
16.09 |
| 2026-02-23 00:00 |
18:40:25.41 |
+10:43:35.8 |
HIP 91586 |
14.88 |
| 2026-02-23 12:00 |
18:40:30.68 |
+10:44:27.4 |
HIP 91586 |
13.74 |
| 2026-02-24 00:00 |
18:40:35.90 |
+10:45:19.2 |
HIP 91586 |
12.68 |