| 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) |
| 2026-05-12 00:00 |
00:16:43.17 |
+35:58:15.2 |
HIP 1492 |
22.92 |
| 2026-05-12 12:00 |
00:16:45.18 |
+35:58:44.0 |
HIP 1492 |
22.49 |
| 2026-05-13 00:00 |
00:16:47.18 |
+35:59:13.0 |
HIP 1492 |
22.08 |
| 2026-05-13 12:00 |
00:16:49.15 |
+35:59:41.9 |
HIP 1492 |
21.68 |
| 2026-05-14 00:00 |
00:16:51.11 |
+36:00:10.9 |
HIP 1492 |
21.30 |
| 2026-05-14 12:00 |
00:16:53.05 |
+36:00:40.0 |
HIP 1492 |
20.93 |
| 2026-05-15 00:00 |
00:16:54.97 |
+36:01:09.1 |
HIP 1492 |
20.57 |
| 2026-05-15 12:00 |
00:16:56.87 |
+36:01:38.3 |
HIP 1492 |
20.24 |
| 2026-05-16 00:00 |
00:16:58.75 |
+36:02:07.5 |
HIP 1492 |
19.92 |
| 2026-05-16 12:00 |
00:17:00.61 |
+36:02:36.7 |
HIP 1492 |
19.62 |
| 2026-05-17 00:00 |
00:17:02.45 |
+36:03:06.0 |
HIP 1492 |
19.34 |
| 2026-05-17 12:00 |
00:17:04.27 |
+36:03:35.3 |
HIP 1492 |
19.08 |
| 2026-05-18 00:00 |
00:17:06.07 |
+36:04:04.6 |
HIP 1492 |
18.84 |
| 2026-05-18 12:00 |
00:17:07.85 |
+36:04:34.0 |
HIP 1492 |
18.62 |
| 2026-05-19 00:00 |
00:17:09.61 |
+36:05:03.4 |
HIP 1492 |
18.42 |
| 2026-05-19 12:00 |
00:17:11.35 |
+36:05:32.9 |
HIP 1492 |
18.24 |
| 2026-05-20 00:00 |
00:17:13.07 |
+36:06:02.3 |
HIP 1492 |
18.09 |
| 2026-05-20 12:00 |
00:17:14.77 |
+36:06:31.8 |
HIP 1492 |
17.96 |
| 2026-05-21 00:00 |
00:17:16.44 |
+36:07:01.3 |
HIP 1492 |
17.85 |
| 2026-05-21 12:00 |
00:17:18.10 |
+36:07:30.8 |
HIP 1492 |
17.77 |
| 2026-05-22 00:00 |
00:17:19.73 |
+36:08:00.4 |
HIP 1492 |
17.71 |
| 2026-05-22 12:00 |
00:17:21.34 |
+36:08:30.0 |
HIP 1492 |
17.68 |
| 2026-05-23 00:00 |
00:17:22.94 |
+36:08:59.5 |
HIP 1492 |
17.66 |
| 2026-05-23 12:00 |
00:17:24.50 |
+36:09:29.1 |
HIP 1492 |
17.67 |
| 2026-05-24 00:00 |
00:17:26.05 |
+36:09:58.7 |
HIP 1492 |
17.71 |
| 2026-05-24 12:00 |
00:17:27.58 |
+36:10:28.3 |
HIP 1492 |
17.76 |
| 2026-05-25 00:00 |
00:17:29.08 |
+36:10:58.0 |
HIP 1492 |
17.84 |
| 2026-05-25 12:00 |
00:17:30.56 |
+36:11:27.6 |
HIP 1492 |
17.94 |
| 2026-05-26 00:00 |
00:17:32.02 |
+36:11:57.2 |
HIP 1492 |
18.07 |
| 2026-05-26 12:00 |
00:17:33.46 |
+36:12:26.9 |
HIP 1492 |
18.21 |
| 2026-05-27 00:00 |
00:17:34.87 |
+36:12:56.5 |
HIP 1492 |
18.37 |
| 2026-05-27 12:00 |
00:17:36.27 |
+36:13:26.1 |
HIP 1492 |
18.55 |
| 2026-05-28 00:00 |
00:17:37.64 |
+36:13:55.8 |
HIP 1492 |
18.75 |
| 2026-05-28 12:00 |
00:17:38.98 |
+36:14:25.4 |
HIP 1336 |
18.63 |
| 2026-05-29 00:00 |
00:17:40.31 |
+36:14:55.0 |
HIP 1403 |
18.17 |
| 2026-05-29 12:00 |
00:17:41.61 |
+36:15:24.7 |
HIP 1403 |
17.70 |
| 2026-05-30 00:00 |
00:17:42.89 |
+36:15:54.3 |
HIP 1403 |
17.24 |
| 2026-05-30 12:00 |
00:17:44.14 |
+36:16:23.9 |
HIP 1403 |
16.78 |
| 2026-05-31 00:00 |
00:17:45.38 |
+36:16:53.5 |
HIP 1403 |
16.33 |
| 2026-05-31 12:00 |
00:17:46.59 |
+36:17:23.0 |
HIP 1403 |
15.88 |
| 2026-06-01 00:00 |
00:17:47.77 |
+36:17:52.6 |
HIP 1403 |
15.44 |
| 2026-06-01 12:00 |
00:17:48.93 |
+36:18:22.1 |
HIP 1403 |
15.00 |
| 2026-06-02 00:00 |
00:17:50.07 |
+36:18:51.7 |
HIP 1403 |
14.57 |