| 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
$$
M_a = (13.517 + 2.899\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.517 |
| n |
2.899 |
| gf |
0.999 |
| gb |
-0.502 |
| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
12:21:52.93 |
-05:49:47.4 |
HIP 60389 |
16.02 |
| 2026-06-03 00:00 |
12:21:52.89 |
-05:48:04.5 |
HIP 60389 |
15.80 |
| 2026-06-03 12:00 |
12:21:53.09 |
-05:46:23.2 |
HIP 60389 |
15.71 |
| 2026-06-04 00:00 |
12:21:53.51 |
-05:44:43.6 |
HIP 60389 |
15.74 |
| 2026-06-04 12:00 |
12:21:54.16 |
-05:43:05.7 |
HIP 60389 |
15.88 |
| 2026-06-05 00:00 |
12:21:55.03 |
-05:41:29.5 |
HIP 60389 |
16.12 |
| 2026-06-05 12:00 |
12:21:56.14 |
-05:39:54.9 |
HIP 60389 |
16.46 |
| 2026-06-06 00:00 |
12:21:57.47 |
-05:38:22.0 |
HIP 60399 |
16.22 |
| 2026-06-06 12:00 |
12:21:59.04 |
-05:36:50.8 |
HIP 60399 |
15.60 |
| 2026-06-07 00:00 |
12:22:00.82 |
-05:35:21.3 |
HIP 60399 |
15.07 |
| 2026-06-07 12:00 |
12:22:02.84 |
-05:33:53.4 |
HIP 60399 |
14.63 |
| 2026-06-08 00:00 |
12:22:05.08 |
-05:32:27.3 |
HIP 60399 |
14.27 |
| 2026-06-08 12:00 |
12:22:07.55 |
-05:31:02.8 |
HIP 60399 |
14.02 |
| 2026-06-09 00:00 |
12:22:10.25 |
-05:29:40.0 |
HIP 60399 |
13.87 |
| 2026-06-09 12:00 |
12:22:13.17 |
-05:28:18.9 |
HIP 60399 |
13.83 |
| 2026-06-10 00:00 |
12:22:16.31 |
-05:26:59.4 |
HIP 60399 |
13.89 |
| 2026-06-10 12:00 |
12:22:19.69 |
-05:25:41.7 |
HIP 60399 |
14.07 |
| 2026-06-11 00:00 |
12:22:23.28 |
-05:24:25.7 |
HIP 60399 |
14.34 |
| 2026-06-11 12:00 |
12:22:27.10 |
-05:23:11.3 |
HIP 60399 |
14.73 |
| 2026-06-12 00:00 |
12:22:31.15 |
-05:21:58.6 |
HIP 60399 |
15.21 |
| 2026-06-12 12:00 |
12:22:35.42 |
-05:20:47.6 |
HIP 60399 |
15.78 |
| 2026-06-13 00:00 |
12:22:39.91 |
-05:19:38.3 |
HIP 60399 |
16.45 |
| 2026-06-13 12:00 |
12:22:44.62 |
-05:18:30.7 |
HIP 60399 |
17.19 |
| 2026-06-14 00:00 |
12:22:49.56 |
-05:17:24.7 |
HIP 60399 |
18.02 |
| 2026-06-14 12:00 |
12:22:54.72 |
-05:16:20.4 |
HIP 60418 |
18.60 |
| 2026-06-15 00:00 |
12:23:00.10 |
-05:15:17.8 |
HIP 60418 |
17.25 |
| 2026-06-15 12:00 |
12:23:05.70 |
-05:14:16.9 |
HIP 60418 |
16.00 |
| 2026-06-16 00:00 |
12:23:11.52 |
-05:13:17.7 |
HIP 60418 |
14.86 |
| 2026-06-16 12:00 |
12:23:17.56 |
-05:12:20.1 |
HIP 60418 |
13.88 |
| 2026-06-17 00:00 |
12:23:23.82 |
-05:11:24.2 |
HIP 60418 |
13.11 |
| 2026-06-17 12:00 |
12:23:30.30 |
-05:10:30.0 |
HIP 60418 |
12.60 |
| 2026-06-18 00:00 |
12:23:36.99 |
-05:09:37.4 |
HIP 60418 |
12.39 |
| 2026-06-18 12:00 |
12:23:43.90 |
-05:08:46.4 |
HIP 60418 |
12.52 |
| 2026-06-19 00:00 |
12:23:51.02 |
-05:07:57.1 |
HIP 60418 |
13.00 |
| 2026-06-19 12:00 |
12:23:58.36 |
-05:07:09.5 |
HIP 60418 |
13.80 |
| 2026-06-20 00:00 |
12:24:05.92 |
-05:06:23.5 |
HIP 60418 |
14.88 |
| 2026-06-20 12:00 |
12:24:13.68 |
-05:05:39.1 |
HIP 60418 |
16.21 |
| 2026-06-21 00:00 |
12:24:21.66 |
-05:04:56.3 |
HIP 60418 |
17.74 |
| 2026-06-21 12:00 |
12:24:29.85 |
-05:04:15.2 |
HIP 60418 |
19.44 |
| 2026-06-22 00:00 |
12:24:38.25 |
-05:03:35.7 |
HIP 60418 |
21.27 |