| Parameter |
Value |
| Designation |
509P/Catalina |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2007-09-05T20:43:57.486720Z |
| Orbit solution date (soln_date, UTC) |
2026-03-31T09:42:45Z |
| Obs used |
595 |
| 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) |
2016-12-03.0000000 |
| e |
0.46347796 |
| q (au) |
3.767635 |
| a (au) |
7.022330 |
| i (deg) |
8.711054 |
| Ω (om, deg) |
275.824608 |
| ω (w, deg) |
179.542774 |
| M (ma, deg) |
178.814254 |
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) |
| 2026-03-26 00:00 |
05:21:27.95 |
+22:58:39.3 |
HIP 25068 |
7.19 |
| 2026-03-26 12:00 |
05:21:56.16 |
+22:58:22.1 |
HIP 25068 |
1.27 |
| 2026-03-27 00:00 |
05:22:24.55 |
+22:58:04.9 |
HIP 25068 |
6.04 |
| 2026-03-27 12:00 |
05:22:53.11 |
+22:57:47.6 |
HIP 25068 |
12.57 |
| 2026-03-28 00:00 |
05:23:21.83 |
+22:57:30.4 |
HIP 25068 |
19.17 |
| 2026-03-28 12:00 |
05:23:50.72 |
+22:57:13.1 |
HIP 25312 |
13.84 |
| 2026-03-29 00:00 |
05:24:19.77 |
+22:56:55.8 |
HIP 25312 |
7.25 |
| 2026-03-29 12:00 |
05:24:48.98 |
+22:56:38.4 |
HIP 25312 |
1.73 |
| 2026-03-30 00:00 |
05:25:18.35 |
+22:56:21.0 |
HIP 25312 |
6.68 |
| 2026-03-30 12:00 |
05:25:47.88 |
+22:56:03.5 |
HIP 25409 |
7.64 |
| 2026-03-31 00:00 |
05:26:17.57 |
+22:55:45.9 |
HIP 25409 |
6.81 |
| 2026-03-31 12:00 |
05:26:47.42 |
+22:55:28.3 |
HIP 25413 |
11.21 |
| 2026-04-01 00:00 |
05:27:17.42 |
+22:55:10.6 |
HIP 25586 |
11.22 |
| 2026-04-01 12:00 |
05:27:47.58 |
+22:54:52.8 |
HIP 25586 |
4.36 |
| 2026-04-02 00:00 |
05:28:17.89 |
+22:54:34.9 |
HIP 25586 |
3.00 |
| 2026-04-02 12:00 |
05:28:48.35 |
+22:54:16.9 |
HIP 25586 |
9.86 |
| 2026-04-03 00:00 |
05:29:18.96 |
+22:53:58.8 |
HIP 25621 |
15.47 |
| 2026-04-03 12:00 |
05:29:49.72 |
+22:53:40.5 |
HIP 25621 |
21.40 |
| 2026-04-04 00:00 |
05:30:20.63 |
+22:53:22.2 |
HIP 25779 |
20.99 |
| 2026-04-04 12:00 |
05:30:51.68 |
+22:53:03.7 |
HIP 25848 |
19.74 |
| 2026-04-05 00:00 |
05:31:22.88 |
+22:52:45.0 |
HIP 25848 |
20.29 |
| 2026-04-05 12:00 |
05:31:54.23 |
+22:52:26.2 |
HIP 26015 |
22.96 |
| 2026-04-06 00:00 |
05:32:25.71 |
+22:52:07.3 |
HIP 26015 |
18.78 |
| 2026-04-06 12:00 |
05:32:57.34 |
+22:51:48.2 |
HIP 26015 |
16.84 |
| 2026-04-07 00:00 |
05:33:29.11 |
+22:51:28.9 |
HIP 26015 |
17.91 |
| 2026-04-07 12:00 |
05:34:01.03 |
+22:51:09.4 |
HIP 26187 |
21.24 |
| 2026-04-08 00:00 |
05:34:33.08 |
+22:50:49.7 |
HIP 26187 |
17.53 |
| 2026-04-08 12:00 |
05:35:05.26 |
+22:50:29.9 |
HIP 26187 |
16.52 |
| 2026-04-09 00:00 |
05:35:37.59 |
+22:50:09.8 |
HIP 26187 |
18.69 |
| 2026-04-09 12:00 |
05:36:10.05 |
+22:49:49.5 |
HIP 26365 |
22.97 |
| 2026-04-10 00:00 |
05:36:42.64 |
+22:49:29.0 |
HIP 26365 |
21.10 |
| 2026-04-10 12:00 |
05:37:15.37 |
+22:49:08.3 |
HIP 26441 |
19.80 |
| 2026-04-11 00:00 |
05:37:48.23 |
+22:48:47.4 |
HIP 26441 |
19.73 |
| 2026-04-11 12:00 |
05:38:21.22 |
+22:48:26.2 |
HIP 26484 |
21.18 |
| 2026-04-12 00:00 |
05:38:54.34 |
+22:48:04.8 |
HIP 26484 |
23.94 |
| 2026-04-12 12:00 |
05:39:27.59 |
+22:47:43.1 |
HIP 26484 |
28.55 |
| 2026-04-13 00:00 |
05:40:00.96 |
+22:47:21.2 |
HIP 26828 |
24.83 |
| 2026-04-13 12:00 |
05:40:34.47 |
+22:46:58.9 |
HIP 26828 |
17.44 |
| 2026-04-14 00:00 |
05:41:08.10 |
+22:46:36.5 |
HIP 26828 |
10.51 |
| 2026-04-14 12:00 |
05:41:41.85 |
+22:46:13.7 |
HIP 26828 |
6.11 |
| 2026-04-15 00:00 |
05:42:15.73 |
+22:45:50.7 |
HIP 26853 |
6.78 |
| 2026-04-15 12:00 |
05:42:49.73 |
+22:45:27.3 |
HIP 26944 |
5.67 |
| 2026-04-16 00:00 |
05:43:23.85 |
+22:45:03.7 |
HIP 26944 |
6.77 |