| Parameter |
Value |
| Designation |
C/1999 F1 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2002-02-13T15:27:28.321920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:57Z |
| Obs used |
166 |
| NEO |
- |
| M1 |
5.900 |
| K1 |
7.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2001-05-25.0000000 |
| e |
0.99912952 |
| q (au) |
5.787019 |
| a (au) |
6648.103893 |
| i (deg) |
92.035388 |
| Ω (om, deg) |
20.023133 |
| ω (w, deg) |
255.157504 |
| M (ma, deg) |
359.999519 |
Magnitude
Scatter + Global Linear
$$
M_a = (0.773 + 5.058\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
0.773 |
| n |
5.058 |
| gf |
0.998 |
| gb |
-0.548 |
| k |
1.000 |
| δ90 |
10.000 |
| 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 |
| 1999-03-13 |
2002-01-17 |
+0.3101 |
-0.124 |
| 2002-02-15 |
2005-08-28 |
-0.2025 |
-0.528 |
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 |
00:12:34.87 |
+35:20:40.0 |
HIP 1048 |
6.79 |
| 2026-03-26 12:00 |
00:12:37.85 |
+35:20:57.1 |
HIP 1048 |
6.41 |
| 2026-03-27 00:00 |
00:12:40.83 |
+35:21:14.4 |
HIP 1048 |
6.07 |
| 2026-03-27 12:00 |
00:12:43.81 |
+35:21:31.8 |
HIP 1048 |
5.81 |
| 2026-03-28 00:00 |
00:12:46.78 |
+35:21:49.5 |
HIP 1048 |
5.61 |
| 2026-03-28 12:00 |
00:12:49.76 |
+35:22:07.3 |
HIP 1048 |
5.49 |
| 2026-03-29 00:00 |
00:12:52.73 |
+35:22:25.3 |
HIP 1048 |
5.46 |
| 2026-03-29 12:00 |
00:12:55.70 |
+35:22:43.5 |
HIP 1048 |
5.51 |
| 2026-03-30 00:00 |
00:12:58.67 |
+35:23:01.9 |
HIP 1048 |
5.65 |
| 2026-03-30 12:00 |
00:13:01.64 |
+35:23:20.4 |
HIP 1048 |
5.87 |
| 2026-03-31 00:00 |
00:13:04.60 |
+35:23:39.2 |
HIP 1048 |
6.15 |
| 2026-03-31 12:00 |
00:13:07.56 |
+35:23:58.1 |
HIP 1048 |
6.50 |
| 2026-04-01 00:00 |
00:13:10.52 |
+35:24:17.2 |
HIP 1048 |
6.90 |
| 2026-04-01 12:00 |
00:13:13.47 |
+35:24:36.4 |
HIP 1048 |
7.35 |
| 2026-04-02 00:00 |
00:13:16.42 |
+35:24:55.9 |
HIP 1048 |
7.83 |
| 2026-04-02 12:00 |
00:13:19.37 |
+35:25:15.5 |
HIP 1048 |
8.34 |
| 2026-04-03 00:00 |
00:13:22.31 |
+35:25:35.3 |
HIP 1048 |
8.88 |
| 2026-04-03 12:00 |
00:13:25.25 |
+35:25:55.2 |
HIP 1048 |
9.44 |
| 2026-04-04 00:00 |
00:13:28.18 |
+35:26:15.3 |
HIP 1137 |
9.22 |
| 2026-04-04 12:00 |
00:13:31.11 |
+35:26:35.6 |
HIP 1137 |
8.68 |
| 2026-04-05 00:00 |
00:13:34.04 |
+35:26:56.1 |
HIP 1137 |
8.17 |
| 2026-04-05 12:00 |
00:13:36.96 |
+35:27:16.7 |
HIP 1137 |
7.68 |
| 2026-04-06 00:00 |
00:13:39.87 |
+35:27:37.5 |
HIP 1137 |
7.23 |
| 2026-04-06 12:00 |
00:13:42.78 |
+35:27:58.4 |
HIP 1137 |
6.81 |
| 2026-04-07 00:00 |
00:13:45.68 |
+35:28:19.5 |
HIP 1137 |
6.45 |
| 2026-04-07 12:00 |
00:13:48.58 |
+35:28:40.8 |
HIP 1137 |
6.15 |
| 2026-04-08 00:00 |
00:13:51.47 |
+35:29:02.3 |
HIP 1137 |
5.92 |
| 2026-04-08 12:00 |
00:13:54.35 |
+35:29:23.8 |
HIP 1137 |
5.76 |
| 2026-04-09 00:00 |
00:13:57.23 |
+35:29:45.6 |
HIP 1137 |
5.68 |
| 2026-04-09 12:00 |
00:14:00.10 |
+35:30:07.5 |
HIP 1137 |
5.69 |
| 2026-04-10 00:00 |
00:14:02.97 |
+35:30:29.6 |
HIP 1137 |
5.79 |
| 2026-04-10 12:00 |
00:14:05.83 |
+35:30:51.8 |
HIP 1137 |
5.97 |
| 2026-04-11 00:00 |
00:14:08.68 |
+35:31:14.1 |
HIP 1137 |
6.22 |
| 2026-04-11 12:00 |
00:14:11.52 |
+35:31:36.7 |
HIP 1137 |
6.54 |
| 2026-04-12 00:00 |
00:14:14.36 |
+35:31:59.3 |
HIP 1137 |
6.91 |
| 2026-04-12 12:00 |
00:14:17.19 |
+35:32:22.1 |
HIP 1137 |
7.33 |
| 2026-04-13 00:00 |
00:14:20.01 |
+35:32:45.1 |
HIP 1137 |
7.80 |
| 2026-04-13 12:00 |
00:14:22.82 |
+35:33:08.2 |
HIP 1137 |
8.29 |
| 2026-04-14 00:00 |
00:14:25.62 |
+35:33:31.5 |
HIP 1137 |
8.82 |
| 2026-04-14 12:00 |
00:14:28.42 |
+35:33:54.9 |
HIP 1137 |
9.37 |
| 2026-04-15 00:00 |
00:14:31.20 |
+35:34:18.4 |
HIP 1137 |
9.93 |
| 2026-04-15 12:00 |
00:14:33.98 |
+35:34:42.1 |
HIP 1137 |
10.52 |
| 2026-04-16 00:00 |
00:14:36.75 |
+35:35:05.9 |
HIP 1137 |
11.11 |