| Parameter |
Value |
| Designation |
257P/Catalina |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-06-04T09:54:55.097280Z |
| Orbit solution date (soln_date, UTC) |
2023-01-14T00:13:33Z |
| Obs used |
2118 |
| NEO |
- |
| M1 |
15.100 |
| K1 |
5.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2014-12-24.0000000 |
| e |
0.43237437 |
| q (au) |
2.130596 |
| a (au) |
3.753523 |
| i (deg) |
20.240315 |
| Ω (om, deg) |
207.850144 |
| ω (w, deg) |
117.883991 |
| M (ma, deg) |
76.926834 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.465 + 2.961\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.465 |
| n |
2.961 |
| gf |
1.000 |
| gb |
-1.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
12:25:31.08 |
-07:28:40.9 |
HIP 60636 |
8.22 |
| 2026-05-12 12:00 |
12:25:21.32 |
-07:25:52.2 |
HIP 60636 |
11.54 |
| 2026-05-13 00:00 |
12:25:11.77 |
-07:23:04.6 |
HIP 60636 |
15.01 |
| 2026-05-13 12:00 |
12:25:02.44 |
-07:20:18.4 |
HIP 60636 |
18.50 |
| 2026-05-14 00:00 |
12:24:53.31 |
-07:17:33.5 |
HIP 60690 |
21.39 |
| 2026-05-14 12:00 |
12:24:44.40 |
-07:14:50.0 |
HIP 60428 |
22.91 |
| 2026-05-15 00:00 |
12:24:35.71 |
-07:12:07.8 |
HIP 60428 |
19.71 |
| 2026-05-15 12:00 |
12:24:27.23 |
-07:09:26.9 |
HIP 60428 |
16.68 |
| 2026-05-16 00:00 |
12:24:18.98 |
-07:06:47.4 |
HIP 60428 |
13.89 |
| 2026-05-16 12:00 |
12:24:10.94 |
-07:04:09.4 |
HIP 60428 |
11.45 |
| 2026-05-17 00:00 |
12:24:03.12 |
-07:01:32.7 |
HIP 60428 |
9.61 |
| 2026-05-17 12:00 |
12:23:55.53 |
-06:58:57.5 |
HIP 60428 |
8.67 |
| 2026-05-18 00:00 |
12:23:48.16 |
-06:56:23.7 |
HIP 60428 |
8.88 |
| 2026-05-18 12:00 |
12:23:41.01 |
-06:53:51.4 |
HIP 60428 |
10.12 |
| 2026-05-19 00:00 |
12:23:34.09 |
-06:51:20.6 |
HIP 60428 |
12.03 |
| 2026-05-19 12:00 |
12:23:27.39 |
-06:48:51.2 |
HIP 60428 |
14.32 |
| 2026-05-20 00:00 |
12:23:20.92 |
-06:46:23.4 |
HIP 60428 |
16.80 |
| 2026-05-20 12:00 |
12:23:14.67 |
-06:43:57.0 |
HIP 60428 |
19.38 |
| 2026-05-21 00:00 |
12:23:08.66 |
-06:41:32.2 |
HIP 60428 |
22.00 |
| 2026-05-21 12:00 |
12:23:02.87 |
-06:39:08.9 |
HIP 60428 |
24.63 |
| 2026-05-22 00:00 |
12:22:57.31 |
-06:36:47.1 |
HIP 60428 |
27.25 |
| 2026-05-22 12:00 |
12:22:51.98 |
-06:34:26.9 |
HIP 60436 |
28.71 |
| 2026-05-23 00:00 |
12:22:46.87 |
-06:32:08.2 |
HIP 60436 |
26.97 |
| 2026-05-23 12:00 |
12:22:42.00 |
-06:29:51.1 |
HIP 60436 |
25.38 |
| 2026-05-24 00:00 |
12:22:37.36 |
-06:27:35.6 |
HIP 60436 |
23.96 |
| 2026-05-24 12:00 |
12:22:32.95 |
-06:25:21.7 |
HIP 60436 |
22.73 |
| 2026-05-25 00:00 |
12:22:28.76 |
-06:23:09.3 |
HIP 60436 |
21.68 |
| 2026-05-25 12:00 |
12:22:24.81 |
-06:20:58.6 |
HIP 60436 |
20.85 |
| 2026-05-26 00:00 |
12:22:21.09 |
-06:18:49.4 |
HIP 60436 |
20.24 |
| 2026-05-26 12:00 |
12:22:17.60 |
-06:16:41.8 |
HIP 60436 |
19.85 |
| 2026-05-27 00:00 |
12:22:14.34 |
-06:14:35.9 |
HIP 60436 |
19.67 |
| 2026-05-27 12:00 |
12:22:11.31 |
-06:12:31.6 |
HIP 60436 |
19.71 |
| 2026-05-28 00:00 |
12:22:08.51 |
-06:10:28.9 |
HIP 60436 |
19.94 |
| 2026-05-28 12:00 |
12:22:05.94 |
-06:08:27.8 |
HIP 60436 |
20.33 |
| 2026-05-29 00:00 |
12:22:03.61 |
-06:06:28.3 |
HIP 60436 |
20.88 |
| 2026-05-29 12:00 |
12:22:01.50 |
-06:04:30.5 |
HIP 60436 |
21.56 |
| 2026-05-30 00:00 |
12:21:59.62 |
-06:02:34.3 |
HIP 60389 |
21.14 |
| 2026-05-30 12:00 |
12:21:57.98 |
-06:00:39.8 |
HIP 60389 |
20.05 |
| 2026-05-31 00:00 |
12:21:56.56 |
-05:58:46.9 |
HIP 60389 |
19.07 |
| 2026-05-31 12:00 |
12:21:55.37 |
-05:56:55.7 |
HIP 60389 |
18.21 |
| 2026-06-01 00:00 |
12:21:54.42 |
-05:55:06.1 |
HIP 60389 |
17.47 |
| 2026-06-01 12:00 |
12:21:53.69 |
-05:53:18.2 |
HIP 60389 |
16.85 |
| 2026-06-02 00:00 |
12:21:53.20 |
-05:51:32.0 |
HIP 60389 |
16.37 |