| 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 · 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
$$
M_a = (7.979 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.979 |
| n |
6.000 |
| gf |
0.997 |
| gb |
-0.776 |
| k |
0.996 |
| δ90 |
9.999 |
| 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 |
2026-02-17 |
+9.7549 |
-5.700 |
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 |
06:15:15.54 |
+22:15:11.1 |
HIP 29689 |
2.55 |
| 2026-05-12 12:00 |
06:15:54.45 |
+22:14:23.3 |
HIP 29689 |
9.16 |
| 2026-05-13 00:00 |
06:16:33.42 |
+22:13:35.0 |
HIP 29827 |
5.49 |
| 2026-05-13 12:00 |
06:17:12.47 |
+22:12:46.2 |
HIP 29867 |
4.52 |
| 2026-05-14 00:00 |
06:17:51.57 |
+22:11:56.7 |
HIP 29867 |
7.95 |
| 2026-05-14 12:00 |
06:18:30.74 |
+22:11:06.6 |
HIP 29867 |
16.48 |
| 2026-05-15 00:00 |
06:19:09.97 |
+22:10:16.0 |
HIP 30075 |
8.93 |
| 2026-05-15 12:00 |
06:19:49.25 |
+22:09:24.7 |
HIP 30075 |
2.92 |
| 2026-05-16 00:00 |
06:20:28.60 |
+22:08:32.9 |
HIP 30075 |
10.22 |
| 2026-05-16 12:00 |
06:21:08.01 |
+22:07:40.4 |
HIP 30075 |
19.20 |
| 2026-05-17 00:00 |
06:21:47.47 |
+22:06:47.3 |
HIP 30268 |
27.26 |
| 2026-05-17 12:00 |
06:22:27.00 |
+22:05:53.6 |
HIP 30343 |
25.92 |
| 2026-05-18 00:00 |
06:23:06.57 |
+22:04:59.3 |
HIP 30343 |
25.93 |
| 2026-05-18 12:00 |
06:23:46.20 |
+22:04:04.4 |
HIP 30560 |
25.09 |
| 2026-05-19 00:00 |
06:24:25.89 |
+22:03:08.9 |
HIP 30560 |
16.38 |
| 2026-05-19 12:00 |
06:25:05.62 |
+22:02:12.7 |
HIP 30560 |
8.84 |
| 2026-05-20 00:00 |
06:25:45.41 |
+22:01:15.9 |
HIP 30560 |
7.70 |
| 2026-05-20 12:00 |
06:26:25.25 |
+22:00:18.5 |
HIP 30723 |
11.79 |
| 2026-05-21 00:00 |
06:27:05.14 |
+21:59:20.4 |
HIP 30723 |
2.51 |
| 2026-05-21 12:00 |
06:27:45.07 |
+21:58:21.7 |
HIP 30723 |
6.83 |
| 2026-05-22 00:00 |
06:28:25.05 |
+21:57:22.4 |
HIP 30771 |
10.42 |
| 2026-05-22 12:00 |
06:29:05.08 |
+21:56:22.4 |
HIP 30771 |
17.27 |
| 2026-05-23 00:00 |
06:29:45.16 |
+21:55:21.8 |
HIP 31053 |
18.25 |
| 2026-05-23 12:00 |
06:30:25.27 |
+21:54:20.5 |
HIP 31053 |
9.65 |
| 2026-05-24 00:00 |
06:31:05.43 |
+21:53:18.6 |
HIP 31053 |
5.34 |
| 2026-05-24 12:00 |
06:31:45.64 |
+21:52:16.1 |
HIP 31053 |
11.83 |
| 2026-05-25 00:00 |
06:32:25.88 |
+21:51:12.9 |
HIP 31053 |
20.68 |
| 2026-05-25 12:00 |
06:33:06.17 |
+21:50:09.0 |
HIP 31316 |
21.53 |
| 2026-05-26 00:00 |
06:33:46.50 |
+21:49:04.5 |
HIP 31366 |
15.70 |
| 2026-05-26 12:00 |
06:34:26.86 |
+21:47:59.3 |
HIP 31366 |
9.72 |
| 2026-05-27 00:00 |
06:35:07.27 |
+21:46:53.5 |
HIP 31366 |
10.98 |
| 2026-05-27 12:00 |
06:35:47.71 |
+21:45:47.0 |
HIP 31366 |
18.04 |
| 2026-05-28 00:00 |
06:36:28.19 |
+21:44:39.8 |
HIP 31663 |
16.21 |
| 2026-05-28 12:00 |
06:37:08.70 |
+21:43:32.0 |
HIP 31663 |
6.73 |
| 2026-05-29 00:00 |
06:37:49.25 |
+21:42:23.5 |
HIP 31663 |
2.76 |
| 2026-05-29 12:00 |
06:38:29.84 |
+21:41:14.4 |
HIP 31663 |
12.25 |
| 2026-05-30 00:00 |
06:39:10.46 |
+21:40:04.6 |
HIP 31848 |
20.62 |
| 2026-05-30 12:00 |
06:39:51.11 |
+21:38:54.1 |
HIP 31848 |
21.79 |
| 2026-05-31 00:00 |
06:40:31.79 |
+21:37:42.9 |
HIP 31848 |
26.57 |
| 2026-05-31 12:00 |
06:41:12.51 |
+21:36:31.1 |
HIP 32164 |
24.75 |
| 2026-06-01 00:00 |
06:41:53.26 |
+21:35:18.5 |
HIP 32164 |
15.26 |
| 2026-06-01 12:00 |
06:42:34.03 |
+21:34:05.3 |
HIP 32164 |
5.97 |
| 2026-06-02 00:00 |
06:43:14.84 |
+21:32:51.5 |
HIP 32164 |
4.59 |