| Parameter |
Value |
| Designation |
509P/Catalina |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2026-04-15T12:31:52.705920Z |
| Orbit solution date (soln_date, UTC) |
2026-04-27T13:42:38Z |
| Obs used |
610 |
| NEO |
- |
| M1 |
7.100 |
| K1 |
16.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2007-02-09T03:20:31.200000Z |
| Discovery magnitude (MPC) |
18.70 N |
| Discovery observatory (MPC) |
703 · University of Arizona Catalina Sky Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-02-24.0000000 |
| e |
0.46351396 |
| q (au) |
3.767292 |
| a (au) |
7.022162 |
| i (deg) |
8.712165 |
| Ω (om, deg) |
275.824612 |
| ω (w, deg) |
179.536914 |
| M (ma, deg) |
183.224564 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.367 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.367 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.792 |
| k |
0.999 |
| 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 |
| 2024-10-03 |
2026-03-29 |
+9.7613 |
-5.661 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
09:06:02.22 |
+12:47:24.0 |
HIP 44581 |
36.72 |
| 2026-09-20 12:00 |
09:06:34.62 |
+12:44:13.5 |
HIP 44862 |
39.81 |
| 2026-09-21 00:00 |
09:07:06.92 |
+12:41:02.9 |
HIP 44862 |
37.58 |
| 2026-09-21 12:00 |
09:07:39.12 |
+12:37:52.2 |
HIP 44862 |
37.21 |
| 2026-09-22 00:00 |
09:08:11.21 |
+12:34:41.4 |
HIP 44843 |
37.79 |
| 2026-09-22 12:00 |
09:08:43.19 |
+12:31:30.5 |
HIP 44843 |
35.40 |
| 2026-09-23 00:00 |
09:09:15.08 |
+12:28:19.6 |
HIP 44843 |
34.93 |
| 2026-09-23 12:00 |
09:09:46.86 |
+12:25:08.6 |
HIP 45028 |
29.60 |
| 2026-09-24 00:00 |
09:10:18.53 |
+12:21:57.5 |
HIP 45028 |
25.42 |
| 2026-09-24 12:00 |
09:10:50.09 |
+12:18:46.4 |
HIP 45028 |
23.57 |
| 2026-09-25 00:00 |
09:11:21.55 |
+12:15:35.2 |
HIP 45216 |
22.69 |
| 2026-09-25 12:00 |
09:11:52.90 |
+12:12:24.0 |
HIP 45216 |
15.23 |
| 2026-09-26 00:00 |
09:12:24.15 |
+12:09:12.8 |
HIP 45216 |
9.35 |
| 2026-09-26 12:00 |
09:12:55.28 |
+12:06:01.5 |
HIP 45216 |
8.91 |
| 2026-09-27 00:00 |
09:13:26.31 |
+12:02:50.1 |
HIP 45216 |
14.40 |
| 2026-09-27 12:00 |
09:13:57.22 |
+11:59:38.8 |
HIP 45216 |
21.67 |
| 2026-09-28 00:00 |
09:14:28.03 |
+11:56:27.4 |
HIP 45345 |
20.45 |
| 2026-09-28 12:00 |
09:14:58.72 |
+11:53:16.0 |
HIP 45345 |
19.05 |
| 2026-09-29 00:00 |
09:15:29.31 |
+11:50:04.6 |
HIP 45345 |
20.98 |
| 2026-09-29 12:00 |
09:15:59.78 |
+11:46:53.2 |
HIP 45345 |
25.47 |
| 2026-09-30 00:00 |
09:16:30.13 |
+11:43:41.8 |
HIP 45614 |
24.11 |
| 2026-09-30 12:00 |
09:17:00.38 |
+11:40:30.4 |
HIP 45614 |
16.27 |
| 2026-10-01 00:00 |
09:17:30.51 |
+11:37:19.1 |
HIP 45614 |
8.87 |
| 2026-10-01 12:00 |
09:18:00.52 |
+11:34:07.7 |
HIP 45614 |
4.64 |
| 2026-10-02 00:00 |
09:18:30.42 |
+11:30:56.4 |
HIP 45614 |
9.61 |
| 2026-10-02 12:00 |
09:19:00.20 |
+11:27:45.1 |
HIP 45614 |
17.02 |
| 2026-10-03 00:00 |
09:19:29.86 |
+11:24:33.9 |
HIP 45809 |
15.81 |
| 2026-10-03 12:00 |
09:19:59.41 |
+11:21:22.7 |
HIP 45809 |
12.24 |
| 2026-10-04 00:00 |
09:20:28.83 |
+11:18:11.6 |
HIP 45809 |
13.22 |
| 2026-10-04 12:00 |
09:20:58.14 |
+11:15:00.5 |
HIP 45809 |
17.98 |
| 2026-10-05 00:00 |
09:21:27.32 |
+11:11:49.5 |
HIP 45990 |
20.06 |
| 2026-10-05 12:00 |
09:21:56.38 |
+11:08:38.6 |
HIP 45990 |
14.60 |
| 2026-10-06 00:00 |
09:22:25.32 |
+11:05:27.8 |
HIP 45990 |
12.07 |
| 2026-10-06 12:00 |
09:22:54.14 |
+11:02:17.0 |
HIP 46069 |
11.61 |
| 2026-10-07 00:00 |
09:23:22.82 |
+10:59:06.4 |
HIP 46069 |
6.45 |
| 2026-10-07 12:00 |
09:23:51.39 |
+10:55:55.9 |
HIP 46069 |
8.21 |
| 2026-10-08 00:00 |
09:24:19.83 |
+10:52:45.5 |
HIP 46069 |
14.53 |
| 2026-10-08 12:00 |
09:24:48.13 |
+10:49:35.2 |
HIP 46106 |
19.29 |
| 2026-10-09 00:00 |
09:25:16.32 |
+10:46:25.1 |
HIP 46106 |
21.35 |
| 2026-10-09 12:00 |
09:25:44.37 |
+10:43:15.1 |
HIP 46189 |
21.06 |
| 2026-10-10 00:00 |
09:26:12.29 |
+10:40:05.2 |
HIP 46189 |
22.95 |
| 2026-10-10 12:00 |
09:26:40.08 |
+10:36:55.6 |
HIP 46189 |
26.88 |
| 2026-10-11 00:00 |
09:27:07.73 |
+10:33:46.0 |
HIP 46431 |
25.32 |