| 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) |
| 2026-03-26 00:00 |
12:51:00.28 |
-12:30:40.2 |
HIP 62668 |
32.35 |
| 2026-03-26 12:00 |
12:50:42.15 |
-12:27:44.7 |
HIP 62497 |
33.70 |
| 2026-03-27 00:00 |
12:50:23.96 |
-12:24:47.9 |
HIP 62497 |
29.86 |
| 2026-03-27 12:00 |
12:50:05.71 |
-12:21:50.0 |
HIP 62497 |
26.53 |
| 2026-03-28 00:00 |
12:49:47.39 |
-12:18:51.0 |
HIP 62579 |
23.76 |
| 2026-03-28 12:00 |
12:49:29.02 |
-12:15:50.8 |
HIP 62579 |
19.99 |
| 2026-03-29 00:00 |
12:49:10.59 |
-12:12:49.5 |
HIP 62579 |
17.09 |
| 2026-03-29 12:00 |
12:48:52.12 |
-12:09:47.1 |
HIP 62579 |
15.60 |
| 2026-03-30 00:00 |
12:48:33.59 |
-12:06:43.7 |
HIP 62579 |
15.94 |
| 2026-03-30 12:00 |
12:48:15.03 |
-12:03:39.2 |
HIP 62579 |
18.01 |
| 2026-03-31 00:00 |
12:47:56.43 |
-12:00:33.7 |
HIP 62399 |
18.71 |
| 2026-03-31 12:00 |
12:47:37.79 |
-11:57:27.2 |
HIP 62345 |
18.51 |
| 2026-04-01 00:00 |
12:47:19.11 |
-11:54:19.7 |
HIP 62345 |
13.02 |
| 2026-04-01 12:00 |
12:47:00.41 |
-11:51:11.3 |
HIP 62345 |
7.59 |
| 2026-04-02 00:00 |
12:46:41.69 |
-11:48:02.0 |
HIP 62345 |
2.71 |
| 2026-04-02 12:00 |
12:46:22.94 |
-11:44:51.8 |
HIP 62345 |
4.36 |
| 2026-04-03 00:00 |
12:46:04.17 |
-11:41:40.8 |
HIP 62345 |
9.65 |
| 2026-04-03 12:00 |
12:45:45.39 |
-11:38:28.9 |
HIP 62345 |
15.17 |
| 2026-04-04 00:00 |
12:45:26.60 |
-11:35:16.1 |
HIP 62345 |
20.75 |
| 2026-04-04 12:00 |
12:45:07.80 |
-11:32:02.6 |
HIP 62164 |
16.73 |
| 2026-04-05 00:00 |
12:44:49.00 |
-11:28:48.4 |
HIP 62164 |
11.40 |
| 2026-04-05 12:00 |
12:44:30.19 |
-11:25:33.4 |
HIP 62164 |
6.58 |
| 2026-04-06 00:00 |
12:44:11.40 |
-11:22:17.7 |
HIP 62164 |
4.49 |
| 2026-04-06 12:00 |
12:43:52.60 |
-11:19:01.3 |
HIP 62164 |
7.80 |
| 2026-04-07 00:00 |
12:43:33.82 |
-11:15:44.2 |
HIP 62164 |
12.86 |
| 2026-04-07 12:00 |
12:43:15.05 |
-11:12:26.6 |
HIP 62164 |
18.27 |
| 2026-04-08 00:00 |
12:42:56.31 |
-11:09:08.4 |
HIP 62164 |
23.80 |
| 2026-04-08 12:00 |
12:42:37.58 |
-11:05:49.5 |
HIP 62164 |
29.38 |
| 2026-04-09 00:00 |
12:42:18.88 |
-11:02:30.2 |
HIP 62164 |
34.99 |
| 2026-04-09 12:00 |
12:42:00.21 |
-10:59:10.4 |
HIP 61776 |
35.68 |
| 2026-04-10 00:00 |
12:41:41.57 |
-10:55:50.0 |
HIP 61776 |
30.44 |
| 2026-04-10 12:00 |
12:41:22.96 |
-10:52:29.3 |
HIP 61776 |
25.40 |
| 2026-04-11 00:00 |
12:41:04.40 |
-10:49:08.1 |
HIP 61776 |
20.69 |
| 2026-04-11 12:00 |
12:40:45.88 |
-10:45:46.5 |
HIP 61776 |
16.59 |
| 2026-04-12 00:00 |
12:40:27.41 |
-10:42:24.6 |
HIP 61776 |
13.67 |
| 2026-04-12 12:00 |
12:40:08.99 |
-10:39:02.3 |
HIP 61776 |
12.75 |
| 2026-04-13 00:00 |
12:39:50.63 |
-10:35:39.8 |
HIP 61776 |
14.21 |
| 2026-04-13 12:00 |
12:39:32.32 |
-10:32:17.0 |
HIP 61776 |
17.46 |
| 2026-04-14 00:00 |
12:39:14.08 |
-10:28:54.0 |
HIP 61776 |
21.70 |
| 2026-04-14 12:00 |
12:38:55.90 |
-10:25:30.7 |
HIP 61776 |
26.46 |
| 2026-04-15 00:00 |
12:38:37.79 |
-10:22:07.3 |
HIP 61776 |
31.50 |
| 2026-04-15 12:00 |
12:38:19.76 |
-10:18:43.8 |
HIP 61508 |
32.57 |
| 2026-04-16 00:00 |
12:38:01.80 |
-10:15:20.2 |
HIP 61508 |
28.92 |