| Parameter |
Value |
| Designation |
C/1990 M1 (McNaught-Hughes) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1991-02-27T15:48:11.756160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
49 |
| NEO |
- |
| M1 |
10.900 |
| K1 |
6.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1990-12-12.0000000 |
| e |
1.00128966 |
| q (au) |
2.682264 |
| a (au) |
-2079.821712 |
| i (deg) |
132.774960 |
| Ω (om, deg) |
233.206314 |
| ω (w, deg) |
18.169676 |
| M (ma, deg) |
-0.000807 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.670 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.670 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.997 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
03:37:05.77 |
+24:23:18.1 |
HIP 16996 |
24.17 |
| 2026-05-12 12:00 |
03:37:07.84 |
+24:23:23.7 |
HIP 16996 |
23.72 |
| 2026-05-13 00:00 |
03:37:09.90 |
+24:23:29.2 |
HIP 16996 |
23.28 |
| 2026-05-13 12:00 |
03:37:11.98 |
+24:23:34.8 |
HIP 16996 |
22.83 |
| 2026-05-14 00:00 |
03:37:14.05 |
+24:23:40.4 |
HIP 16996 |
22.39 |
| 2026-05-14 12:00 |
03:37:16.12 |
+24:23:46.1 |
HIP 16996 |
21.94 |
| 2026-05-15 00:00 |
03:37:18.19 |
+24:23:51.7 |
HIP 16996 |
21.50 |
| 2026-05-15 12:00 |
03:37:20.27 |
+24:23:57.4 |
HIP 16996 |
21.06 |
| 2026-05-16 00:00 |
03:37:22.34 |
+24:24:03.1 |
HIP 16996 |
20.62 |
| 2026-05-16 12:00 |
03:37:24.42 |
+24:24:08.8 |
HIP 16996 |
20.18 |
| 2026-05-17 00:00 |
03:37:26.49 |
+24:24:14.6 |
HIP 16996 |
19.75 |
| 2026-05-17 12:00 |
03:37:28.57 |
+24:24:20.4 |
HIP 16996 |
19.31 |
| 2026-05-18 00:00 |
03:37:30.65 |
+24:24:26.2 |
HIP 16996 |
18.88 |
| 2026-05-18 12:00 |
03:37:32.72 |
+24:24:32.0 |
HIP 16996 |
18.45 |
| 2026-05-19 00:00 |
03:37:34.80 |
+24:24:37.8 |
HIP 16996 |
18.02 |
| 2026-05-19 12:00 |
03:37:36.87 |
+24:24:43.7 |
HIP 16996 |
17.60 |
| 2026-05-20 00:00 |
03:37:38.95 |
+24:24:49.5 |
HIP 16996 |
17.17 |
| 2026-05-20 12:00 |
03:37:41.02 |
+24:24:55.4 |
HIP 16996 |
16.76 |
| 2026-05-21 00:00 |
03:37:43.10 |
+24:25:01.3 |
HIP 16996 |
16.34 |
| 2026-05-21 12:00 |
03:37:45.17 |
+24:25:07.2 |
HIP 16996 |
15.93 |
| 2026-05-22 00:00 |
03:37:47.24 |
+24:25:13.2 |
HIP 16996 |
15.52 |
| 2026-05-22 12:00 |
03:37:49.31 |
+24:25:19.1 |
HIP 16996 |
15.12 |
| 2026-05-23 00:00 |
03:37:51.38 |
+24:25:25.1 |
HIP 16996 |
14.72 |
| 2026-05-23 12:00 |
03:37:53.44 |
+24:25:31.1 |
HIP 16996 |
14.33 |
| 2026-05-24 00:00 |
03:37:55.51 |
+24:25:37.1 |
HIP 16996 |
13.94 |
| 2026-05-24 12:00 |
03:37:57.57 |
+24:25:43.1 |
HIP 16996 |
13.56 |
| 2026-05-25 00:00 |
03:37:59.63 |
+24:25:49.1 |
HIP 16996 |
13.18 |
| 2026-05-25 12:00 |
03:38:01.69 |
+24:25:55.1 |
HIP 16996 |
12.81 |
| 2026-05-26 00:00 |
03:38:03.75 |
+24:26:01.2 |
HIP 16996 |
12.45 |
| 2026-05-26 12:00 |
03:38:05.80 |
+24:26:07.2 |
HIP 16996 |
12.10 |
| 2026-05-27 00:00 |
03:38:07.85 |
+24:26:13.3 |
HIP 16996 |
11.76 |
| 2026-05-27 12:00 |
03:38:09.90 |
+24:26:19.4 |
HIP 16996 |
11.43 |
| 2026-05-28 00:00 |
03:38:11.95 |
+24:26:25.5 |
HIP 16996 |
11.10 |
| 2026-05-28 12:00 |
03:38:13.99 |
+24:26:31.6 |
HIP 16996 |
10.79 |
| 2026-05-29 00:00 |
03:38:16.03 |
+24:26:37.7 |
HIP 16996 |
10.50 |
| 2026-05-29 12:00 |
03:38:18.06 |
+24:26:43.8 |
HIP 16996 |
10.21 |
| 2026-05-30 00:00 |
03:38:20.10 |
+24:26:49.9 |
HIP 16996 |
9.94 |
| 2026-05-30 12:00 |
03:38:22.13 |
+24:26:56.1 |
HIP 16996 |
9.69 |
| 2026-05-31 00:00 |
03:38:24.15 |
+24:27:02.2 |
HIP 16996 |
9.45 |
| 2026-05-31 12:00 |
03:38:26.17 |
+24:27:08.4 |
HIP 16996 |
9.23 |
| 2026-06-01 00:00 |
03:38:28.19 |
+24:27:14.5 |
HIP 16996 |
9.03 |
| 2026-06-01 12:00 |
03:38:30.21 |
+24:27:20.7 |
HIP 16996 |
8.85 |
| 2026-06-02 00:00 |
03:38:32.22 |
+24:27:26.9 |
HIP 16996 |
8.69 |