| Parameter |
Value |
| Designation |
C/2018 M1 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-07-10T00:35:11.529600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:44Z |
| Obs used |
171 |
| NEO |
- |
| M1 |
16.600 |
| K1 |
5.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-06-25T10:26:00.672000Z |
| Discovery magnitude (MPC) |
17.60 G |
| Discovery observatory (MPC) |
703 · Catalina Sky Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-08-16.0000000 |
| e |
0.93870003 |
| q (au) |
1.303480 |
| a (au) |
21.263951 |
| i (deg) |
37.257024 |
| Ω (om, deg) |
339.463309 |
| ω (w, deg) |
14.132786 |
| M (ma, deg) |
0.371666 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.433 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.433 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.965 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
10:13:11.94 |
+16:52:05.0 |
HIP 50053 |
9.15 |
| 2026-05-12 12:00 |
10:13:11.16 |
+16:51:54.4 |
HIP 50053 |
9.32 |
| 2026-05-13 00:00 |
10:13:10.43 |
+16:51:43.4 |
HIP 50053 |
9.49 |
| 2026-05-13 12:00 |
10:13:09.75 |
+16:51:32.2 |
HIP 50053 |
9.68 |
| 2026-05-14 00:00 |
10:13:09.13 |
+16:51:20.7 |
HIP 50053 |
9.87 |
| 2026-05-14 12:00 |
10:13:08.56 |
+16:51:08.9 |
HIP 50053 |
10.07 |
| 2026-05-15 00:00 |
10:13:08.04 |
+16:50:56.8 |
HIP 50053 |
10.27 |
| 2026-05-15 12:00 |
10:13:07.58 |
+16:50:44.5 |
HIP 50053 |
10.48 |
| 2026-05-16 00:00 |
10:13:07.17 |
+16:50:31.8 |
HIP 50053 |
10.70 |
| 2026-05-16 12:00 |
10:13:06.81 |
+16:50:18.9 |
HIP 50053 |
10.92 |
| 2026-05-17 00:00 |
10:13:06.50 |
+16:50:05.7 |
HIP 50053 |
11.14 |
| 2026-05-17 12:00 |
10:13:06.25 |
+16:49:52.2 |
HIP 50053 |
11.37 |
| 2026-05-18 00:00 |
10:13:06.05 |
+16:49:38.4 |
HIP 50053 |
11.60 |
| 2026-05-18 12:00 |
10:13:05.91 |
+16:49:24.4 |
HIP 50053 |
11.84 |
| 2026-05-19 00:00 |
10:13:05.81 |
+16:49:10.1 |
HIP 50053 |
12.08 |
| 2026-05-19 12:00 |
10:13:05.77 |
+16:48:55.5 |
HIP 50053 |
12.32 |
| 2026-05-20 00:00 |
10:13:05.79 |
+16:48:40.6 |
HIP 50053 |
12.57 |
| 2026-05-20 12:00 |
10:13:05.85 |
+16:48:25.5 |
HIP 50053 |
12.82 |
| 2026-05-21 00:00 |
10:13:05.97 |
+16:48:10.0 |
HIP 50053 |
13.07 |
| 2026-05-21 12:00 |
10:13:06.14 |
+16:47:54.4 |
HIP 50053 |
13.33 |
| 2026-05-22 00:00 |
10:13:06.36 |
+16:47:38.4 |
HIP 50053 |
13.59 |
| 2026-05-22 12:00 |
10:13:06.63 |
+16:47:22.2 |
HIP 50053 |
13.86 |
| 2026-05-23 00:00 |
10:13:06.96 |
+16:47:05.7 |
HIP 50053 |
14.13 |
| 2026-05-23 12:00 |
10:13:07.34 |
+16:46:49.0 |
HIP 50053 |
14.41 |
| 2026-05-24 00:00 |
10:13:07.77 |
+16:46:32.0 |
HIP 50053 |
14.69 |
| 2026-05-24 12:00 |
10:13:08.25 |
+16:46:14.7 |
HIP 50040 |
14.49 |
| 2026-05-25 00:00 |
10:13:08.78 |
+16:45:57.2 |
HIP 50040 |
14.22 |
| 2026-05-25 12:00 |
10:13:09.36 |
+16:45:39.4 |
HIP 50040 |
13.95 |
| 2026-05-26 00:00 |
10:13:10.00 |
+16:45:21.3 |
HIP 50040 |
13.68 |
| 2026-05-26 12:00 |
10:13:10.68 |
+16:45:03.1 |
HIP 50040 |
13.41 |
| 2026-05-27 00:00 |
10:13:11.42 |
+16:44:44.5 |
HIP 50040 |
13.14 |
| 2026-05-27 12:00 |
10:13:12.20 |
+16:44:25.7 |
HIP 50040 |
12.88 |
| 2026-05-28 00:00 |
10:13:13.04 |
+16:44:06.6 |
HIP 50040 |
12.62 |
| 2026-05-28 12:00 |
10:13:13.93 |
+16:43:47.3 |
HIP 50040 |
12.37 |
| 2026-05-29 00:00 |
10:13:14.86 |
+16:43:27.8 |
HIP 50040 |
12.12 |
| 2026-05-29 12:00 |
10:13:15.85 |
+16:43:08.0 |
HIP 50040 |
11.89 |
| 2026-05-30 00:00 |
10:13:16.89 |
+16:42:47.9 |
HIP 50040 |
11.66 |
| 2026-05-30 12:00 |
10:13:17.98 |
+16:42:27.6 |
HIP 50040 |
11.44 |
| 2026-05-31 00:00 |
10:13:19.11 |
+16:42:07.1 |
HIP 50040 |
11.24 |
| 2026-05-31 12:00 |
10:13:20.30 |
+16:41:46.3 |
HIP 50040 |
11.05 |
| 2026-06-01 00:00 |
10:13:21.53 |
+16:41:25.3 |
HIP 50040 |
10.88 |
| 2026-06-01 12:00 |
10:13:22.82 |
+16:41:04.0 |
HIP 50040 |
10.73 |
| 2026-06-02 00:00 |
10:13:24.15 |
+16:40:42.5 |
HIP 50040 |
10.60 |