C/2018 M1 (Catalina)
| 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) |
| 2026-02-03 00:00 |
10:28:33.55 |
+16:00:19.4 |
HIP 51279 |
15.07 |
| 2026-02-03 12:00 |
10:28:27.58 |
+16:00:51.4 |
HIP 51279 |
15.51 |
| 2026-02-04 00:00 |
10:28:21.59 |
+16:01:23.4 |
HIP 51279 |
16.08 |
| 2026-02-04 12:00 |
10:28:15.58 |
+16:01:55.4 |
HIP 51279 |
16.78 |
| 2026-02-05 00:00 |
10:28:09.54 |
+16:02:27.5 |
HIP 51279 |
17.59 |
| 2026-02-05 12:00 |
10:28:03.49 |
+16:02:59.5 |
HIP 51201 |
18.42 |
| 2026-02-06 00:00 |
10:27:57.41 |
+16:03:31.6 |
HIP 51221 |
17.88 |
| 2026-02-06 12:00 |
10:27:51.32 |
+16:04:03.7 |
HIP 51221 |
17.13 |
| 2026-02-07 00:00 |
10:27:45.20 |
+16:04:35.7 |
HIP 51221 |
16.50 |
| 2026-02-07 12:00 |
10:27:39.07 |
+16:05:07.8 |
HIP 51221 |
16.00 |
| 2026-02-08 00:00 |
10:27:32.92 |
+16:05:39.8 |
HIP 51221 |
15.64 |
| 2026-02-08 12:00 |
10:27:26.75 |
+16:06:11.8 |
HIP 51221 |
15.43 |
| 2026-02-09 00:00 |
10:27:20.57 |
+16:06:43.8 |
HIP 51221 |
15.38 |
| 2026-02-09 12:00 |
10:27:14.37 |
+16:07:15.8 |
HIP 51221 |
15.50 |
| 2026-02-10 00:00 |
10:27:08.15 |
+16:07:47.8 |
HIP 51221 |
15.77 |
| 2026-02-10 12:00 |
10:27:01.92 |
+16:08:19.7 |
HIP 51221 |
16.20 |
| 2026-02-11 00:00 |
10:26:55.68 |
+16:08:51.6 |
HIP 51221 |
16.77 |
| 2026-02-11 12:00 |
10:26:49.42 |
+16:09:23.4 |
HIP 51221 |
17.48 |
| 2026-02-12 00:00 |
10:26:43.15 |
+16:09:55.3 |
HIP 51221 |
18.29 |
| 2026-02-12 12:00 |
10:26:36.86 |
+16:10:27.0 |
HIP 51221 |
19.21 |
| 2026-02-13 00:00 |
10:26:30.56 |
+16:10:58.8 |
HIP 51221 |
20.22 |
| 2026-02-13 12:00 |
10:26:24.26 |
+16:11:30.4 |
HIP 51221 |
21.30 |
| 2026-02-14 00:00 |
10:26:17.94 |
+16:12:02.1 |
HIP 51221 |
22.44 |
| 2026-02-14 12:00 |
10:26:11.61 |
+16:12:33.6 |
HIP 51221 |
23.65 |
| 2026-02-15 00:00 |
10:26:05.27 |
+16:13:05.1 |
HIP 51221 |
24.90 |
| 2026-02-15 12:00 |
10:25:58.92 |
+16:13:36.6 |
HIP 51221 |
26.19 |
| 2026-02-16 00:00 |
10:25:52.56 |
+16:14:08.0 |
HIP 51221 |
27.52 |
| 2026-02-16 12:00 |
10:25:46.20 |
+16:14:39.3 |
HIP 51221 |
28.88 |
| 2026-02-17 00:00 |
10:25:39.83 |
+16:15:10.5 |
HIP 51221 |
30.26 |
| 2026-02-17 12:00 |
10:25:33.45 |
+16:15:41.6 |
HIP 51221 |
31.67 |
| 2026-02-18 00:00 |
10:25:27.07 |
+16:16:12.7 |
HIP 51221 |
33.10 |
| 2026-02-18 12:00 |
10:25:20.68 |
+16:16:43.7 |
HIP 51221 |
34.55 |
| 2026-02-19 00:00 |
10:25:14.29 |
+16:17:14.6 |
HIP 51221 |
36.01 |
| 2026-02-19 12:00 |
10:25:07.89 |
+16:17:45.3 |
HIP 51221 |
37.48 |
| 2026-02-20 00:00 |
10:25:01.49 |
+16:18:16.0 |
HIP 51020 |
37.32 |
| 2026-02-20 12:00 |
10:24:55.09 |
+16:18:46.6 |
HIP 51020 |
37.06 |
| 2026-02-21 00:00 |
10:24:48.68 |
+16:19:17.1 |
HIP 51020 |
36.88 |
| 2026-02-21 12:00 |
10:24:42.28 |
+16:19:47.5 |
HIP 51020 |
36.76 |
| 2026-02-22 00:00 |
10:24:35.87 |
+16:20:17.8 |
HIP 50784 |
35.84 |
| 2026-02-22 12:00 |
10:24:29.47 |
+16:20:47.9 |
HIP 50784 |
34.23 |
| 2026-02-23 00:00 |
10:24:23.06 |
+16:21:17.9 |
HIP 50784 |
32.62 |
| 2026-02-23 12:00 |
10:24:16.66 |
+16:21:47.9 |
HIP 50784 |
31.02 |
| 2026-02-24 00:00 |
10:24:10.25 |
+16:22:17.6 |
HIP 50784 |
29.41 |