| 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 |
9.976 |
| 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) |
| 2026-06-01 00:00 |
18:39:51.35 |
+13:37:11.2 |
HIP 91569 |
16.73 |
| 2026-06-01 12:00 |
18:39:46.07 |
+13:37:38.8 |
HIP 91569 |
17.73 |
| 2026-06-02 00:00 |
18:39:40.76 |
+13:38:06.0 |
HIP 91569 |
18.78 |
| 2026-06-02 12:00 |
18:39:35.41 |
+13:38:32.6 |
HIP 91569 |
19.87 |
| 2026-06-03 00:00 |
18:39:30.03 |
+13:38:58.8 |
HIP 91569 |
20.99 |
| 2026-06-03 12:00 |
18:39:24.62 |
+13:39:24.4 |
HIP 91569 |
22.14 |
| 2026-06-04 00:00 |
18:39:19.18 |
+13:39:49.5 |
HIP 91569 |
23.30 |
| 2026-06-04 12:00 |
18:39:13.71 |
+13:40:14.1 |
HIP 91569 |
24.50 |
| 2026-06-05 00:00 |
18:39:08.21 |
+13:40:38.2 |
HIP 91569 |
25.71 |
| 2026-06-05 12:00 |
18:39:02.68 |
+13:41:01.7 |
HIP 91294 |
25.57 |
| 2026-06-06 00:00 |
18:38:57.11 |
+13:41:24.8 |
HIP 91294 |
24.22 |
| 2026-06-06 12:00 |
18:38:51.53 |
+13:41:47.3 |
HIP 91294 |
22.86 |
| 2026-06-07 00:00 |
18:38:45.91 |
+13:42:09.3 |
HIP 91294 |
21.50 |
| 2026-06-07 12:00 |
18:38:40.27 |
+13:42:30.7 |
HIP 91294 |
20.15 |
| 2026-06-08 00:00 |
18:38:34.59 |
+13:42:51.6 |
HIP 91294 |
18.80 |
| 2026-06-08 12:00 |
18:38:28.90 |
+13:43:12.0 |
HIP 91294 |
17.44 |
| 2026-06-09 00:00 |
18:38:23.17 |
+13:43:31.9 |
HIP 91294 |
16.10 |
| 2026-06-09 12:00 |
18:38:17.42 |
+13:43:51.2 |
HIP 91294 |
14.76 |
| 2026-06-10 00:00 |
18:38:11.65 |
+13:44:09.9 |
HIP 91294 |
13.44 |
| 2026-06-10 12:00 |
18:38:05.85 |
+13:44:28.2 |
HIP 91294 |
12.13 |
| 2026-06-11 00:00 |
18:38:00.03 |
+13:44:45.9 |
HIP 91294 |
10.85 |
| 2026-06-11 12:00 |
18:37:54.19 |
+13:45:03.0 |
HIP 91294 |
9.61 |
| 2026-06-12 00:00 |
18:37:48.32 |
+13:45:19.6 |
HIP 91294 |
8.43 |
| 2026-06-12 12:00 |
18:37:42.43 |
+13:45:35.6 |
HIP 91294 |
7.33 |
| 2026-06-13 00:00 |
18:37:36.52 |
+13:45:51.1 |
HIP 91294 |
6.36 |
| 2026-06-13 12:00 |
18:37:30.59 |
+13:46:06.0 |
HIP 91294 |
5.61 |
| 2026-06-14 00:00 |
18:37:24.64 |
+13:46:20.4 |
HIP 91294 |
5.15 |
| 2026-06-14 12:00 |
18:37:18.66 |
+13:46:34.2 |
HIP 91294 |
5.08 |
| 2026-06-15 00:00 |
18:37:12.67 |
+13:46:47.5 |
HIP 91294 |
5.42 |
| 2026-06-15 12:00 |
18:37:06.67 |
+13:47:00.2 |
HIP 91294 |
6.09 |
| 2026-06-16 00:00 |
18:37:00.64 |
+13:47:12.3 |
HIP 91294 |
7.01 |
| 2026-06-16 12:00 |
18:36:54.60 |
+13:47:23.8 |
HIP 91294 |
8.09 |
| 2026-06-17 00:00 |
18:36:48.54 |
+13:47:34.8 |
HIP 91294 |
9.28 |
| 2026-06-17 12:00 |
18:36:42.46 |
+13:47:45.3 |
HIP 91294 |
10.55 |
| 2026-06-18 00:00 |
18:36:36.37 |
+13:47:55.2 |
HIP 91294 |
11.86 |
| 2026-06-18 12:00 |
18:36:30.26 |
+13:48:04.5 |
HIP 91294 |
13.20 |
| 2026-06-19 00:00 |
18:36:24.15 |
+13:48:13.2 |
HIP 91294 |
14.58 |
| 2026-06-19 12:00 |
18:36:18.01 |
+13:48:21.4 |
HIP 91294 |
15.97 |
| 2026-06-20 00:00 |
18:36:11.87 |
+13:48:29.0 |
HIP 91294 |
17.38 |
| 2026-06-20 12:00 |
18:36:05.71 |
+13:48:36.0 |
HIP 91294 |
18.81 |
| 2026-06-21 00:00 |
18:35:59.54 |
+13:48:42.5 |
HIP 91294 |
20.24 |
| 2026-06-21 12:00 |
18:35:53.36 |
+13:48:48.4 |
HIP 91294 |
21.68 |
| 2026-06-22 00:00 |
18:35:47.18 |
+13:48:53.7 |
HIP 91294 |
23.13 |