| Parameter |
Value |
| Designation |
499P/Catalina |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2025-03-04T09:55:03.910080Z |
| Orbit solution date (soln_date, UTC) |
2025-09-09T12:43:01Z |
| Obs used |
468 |
| NEO |
Yes |
| M1 |
19.600 |
| K1 |
4.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2024-02-28.0000000 |
| e |
0.69137458 |
| q (au) |
0.930634 |
| a (au) |
3.015417 |
| i (deg) |
24.586385 |
| Ω (om, deg) |
139.328525 |
| ω (w, deg) |
2.563338 |
| M (ma, deg) |
290.278038 |
Magnitude
Scatter + Global Linear
$$
M_a = (19.673 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
19.673 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.800 |
| δ90 |
1.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
20:17:09.77 |
-08:16:31.9 |
HIP 100054 |
17.11 |
| 2026-03-26 12:00 |
20:17:30.31 |
-08:15:03.7 |
HIP 100054 |
12.87 |
| 2026-03-27 00:00 |
20:17:50.68 |
-08:13:35.6 |
HIP 100054 |
9.74 |
| 2026-03-27 12:00 |
20:18:10.87 |
-08:12:07.7 |
HIP 100054 |
8.89 |
| 2026-03-28 00:00 |
20:18:30.88 |
-08:10:40.0 |
HIP 100054 |
10.80 |
| 2026-03-28 12:00 |
20:18:50.72 |
-08:09:12.5 |
HIP 100054 |
14.37 |
| 2026-03-29 00:00 |
20:19:10.37 |
-08:07:45.2 |
HIP 100054 |
18.63 |
| 2026-03-29 12:00 |
20:19:29.84 |
-08:06:18.1 |
HIP 100235 |
21.25 |
| 2026-03-30 00:00 |
20:19:49.14 |
-08:04:51.1 |
HIP 100235 |
22.34 |
| 2026-03-30 12:00 |
20:20:08.25 |
-08:03:24.4 |
HIP 100326 |
21.11 |
| 2026-03-31 00:00 |
20:20:27.17 |
-08:01:58.0 |
HIP 100326 |
18.03 |
| 2026-03-31 12:00 |
20:20:45.92 |
-08:00:31.7 |
HIP 100326 |
15.89 |
| 2026-04-01 00:00 |
20:21:04.48 |
-07:59:05.8 |
HIP 100326 |
15.07 |
| 2026-04-01 12:00 |
20:21:22.86 |
-07:57:40.0 |
HIP 100326 |
15.73 |
| 2026-04-02 00:00 |
20:21:41.05 |
-07:56:14.5 |
HIP 100326 |
17.66 |
| 2026-04-02 12:00 |
20:21:59.05 |
-07:54:49.3 |
HIP 100326 |
20.49 |
| 2026-04-03 00:00 |
20:22:16.86 |
-07:53:24.4 |
HIP 100326 |
23.86 |
| 2026-04-03 12:00 |
20:22:34.49 |
-07:51:59.8 |
HIP 100596 |
25.57 |
| 2026-04-04 00:00 |
20:22:51.93 |
-07:50:35.4 |
HIP 100596 |
21.40 |
| 2026-04-04 12:00 |
20:23:09.18 |
-07:49:11.4 |
HIP 100596 |
17.46 |
| 2026-04-05 00:00 |
20:23:26.24 |
-07:47:47.6 |
HIP 100596 |
13.88 |
| 2026-04-05 12:00 |
20:23:43.10 |
-07:46:24.2 |
HIP 100596 |
10.98 |
| 2026-04-06 00:00 |
20:23:59.77 |
-07:45:01.2 |
HIP 100596 |
9.34 |
| 2026-04-06 12:00 |
20:24:16.25 |
-07:43:38.4 |
HIP 100596 |
9.56 |
| 2026-04-07 00:00 |
20:24:32.53 |
-07:42:16.0 |
HIP 100683 |
6.69 |
| 2026-04-07 12:00 |
20:24:48.62 |
-07:40:54.0 |
HIP 100683 |
4.59 |
| 2026-04-08 00:00 |
20:25:04.51 |
-07:39:32.4 |
HIP 100683 |
5.69 |
| 2026-04-08 12:00 |
20:25:20.21 |
-07:38:11.1 |
HIP 100683 |
8.81 |
| 2026-04-09 00:00 |
20:25:35.70 |
-07:36:50.2 |
HIP 100778 |
9.57 |
| 2026-04-09 12:00 |
20:25:50.99 |
-07:35:29.7 |
HIP 100778 |
8.93 |
| 2026-04-10 00:00 |
20:26:06.09 |
-07:34:09.6 |
HIP 100778 |
9.99 |
| 2026-04-10 12:00 |
20:26:20.98 |
-07:32:50.0 |
HIP 100778 |
12.28 |
| 2026-04-11 00:00 |
20:26:35.66 |
-07:31:30.8 |
HIP 100778 |
15.22 |
| 2026-04-11 12:00 |
20:26:50.15 |
-07:30:12.0 |
HIP 100778 |
18.46 |
| 2026-04-12 00:00 |
20:27:04.43 |
-07:28:53.6 |
HIP 100959 |
16.26 |
| 2026-04-12 12:00 |
20:27:18.50 |
-07:27:35.8 |
HIP 100959 |
12.81 |
| 2026-04-13 00:00 |
20:27:32.36 |
-07:26:18.4 |
HIP 100959 |
9.62 |
| 2026-04-13 12:00 |
20:27:46.02 |
-07:25:01.4 |
HIP 100959 |
6.96 |
| 2026-04-14 00:00 |
20:27:59.47 |
-07:23:45.0 |
HIP 100959 |
5.54 |
| 2026-04-14 12:00 |
20:28:12.71 |
-07:22:29.1 |
HIP 100959 |
6.19 |
| 2026-04-15 00:00 |
20:28:25.73 |
-07:21:13.7 |
HIP 100959 |
8.37 |
| 2026-04-15 12:00 |
20:28:38.54 |
-07:19:58.8 |
HIP 100959 |
11.18 |
| 2026-04-16 00:00 |
20:28:51.14 |
-07:18:44.5 |
HIP 100959 |
14.21 |