| 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 |
-0.998 |
| 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) |
| 2026-07-29 00:00 |
03:41:22.16 |
+24:37:51.9 |
HIP 17044 |
30.88 |
| 2026-07-29 12:00 |
03:41:22.88 |
+24:37:55.7 |
HIP 17044 |
31.06 |
| 2026-07-30 00:00 |
03:41:23.60 |
+24:37:59.5 |
HIP 17044 |
31.24 |
| 2026-07-30 12:00 |
03:41:24.29 |
+24:38:03.2 |
HIP 17044 |
31.40 |
| 2026-07-31 00:00 |
03:41:24.97 |
+24:38:06.9 |
HIP 17044 |
31.57 |
| 2026-07-31 12:00 |
03:41:25.63 |
+24:38:10.6 |
HIP 17044 |
31.73 |
| 2026-08-01 00:00 |
03:41:26.28 |
+24:38:14.2 |
HIP 17044 |
31.89 |
| 2026-08-01 12:00 |
03:41:26.91 |
+24:38:17.7 |
HIP 17044 |
32.04 |
| 2026-08-02 00:00 |
03:41:27.52 |
+24:38:21.2 |
HIP 17044 |
32.20 |
| 2026-08-02 12:00 |
03:41:28.11 |
+24:38:24.7 |
HIP 17044 |
32.34 |
| 2026-08-03 00:00 |
03:41:28.69 |
+24:38:28.1 |
HIP 17034 |
32.47 |
| 2026-08-03 12:00 |
03:41:29.25 |
+24:38:31.5 |
HIP 17034 |
32.59 |
| 2026-08-04 00:00 |
03:41:29.80 |
+24:38:34.8 |
HIP 17034 |
32.70 |
| 2026-08-04 12:00 |
03:41:30.32 |
+24:38:38.0 |
HIP 17034 |
32.82 |
| 2026-08-05 00:00 |
03:41:30.83 |
+24:38:41.3 |
HIP 17034 |
32.93 |
| 2026-08-05 12:00 |
03:41:31.32 |
+24:38:44.4 |
HIP 17034 |
33.03 |
| 2026-08-06 00:00 |
03:41:31.80 |
+24:38:47.6 |
HIP 17034 |
33.13 |
| 2026-08-06 12:00 |
03:41:32.26 |
+24:38:50.6 |
HIP 17034 |
33.23 |
| 2026-08-07 00:00 |
03:41:32.70 |
+24:38:53.7 |
HIP 17034 |
33.33 |
| 2026-08-07 12:00 |
03:41:33.12 |
+24:38:56.6 |
HIP 17034 |
33.42 |
| 2026-08-08 00:00 |
03:41:33.52 |
+24:38:59.6 |
HIP 17034 |
33.50 |
| 2026-08-08 12:00 |
03:41:33.91 |
+24:39:02.4 |
HIP 17034 |
33.59 |
| 2026-08-09 00:00 |
03:41:34.28 |
+24:39:05.3 |
HIP 17034 |
33.67 |
| 2026-08-09 12:00 |
03:41:34.63 |
+24:39:08.0 |
HIP 17034 |
33.74 |
| 2026-08-10 00:00 |
03:41:34.97 |
+24:39:10.8 |
HIP 17034 |
33.81 |
| 2026-08-10 12:00 |
03:41:35.28 |
+24:39:13.4 |
HIP 17034 |
33.88 |
| 2026-08-11 00:00 |
03:41:35.58 |
+24:39:16.1 |
HIP 17034 |
33.94 |
| 2026-08-11 12:00 |
03:41:35.86 |
+24:39:18.6 |
HIP 17034 |
34.00 |
| 2026-08-12 00:00 |
03:41:36.12 |
+24:39:21.1 |
HIP 17034 |
34.06 |
| 2026-08-12 12:00 |
03:41:36.37 |
+24:39:23.6 |
HIP 17034 |
34.11 |
| 2026-08-13 00:00 |
03:41:36.59 |
+24:39:26.0 |
HIP 17034 |
34.16 |
| 2026-08-13 12:00 |
03:41:36.80 |
+24:39:28.4 |
HIP 17034 |
34.20 |
| 2026-08-14 00:00 |
03:41:36.99 |
+24:39:30.7 |
HIP 17034 |
34.24 |
| 2026-08-14 12:00 |
03:41:37.16 |
+24:39:32.9 |
HIP 17034 |
34.28 |
| 2026-08-15 00:00 |
03:41:37.32 |
+24:39:35.1 |
HIP 17034 |
34.31 |
| 2026-08-15 12:00 |
03:41:37.45 |
+24:39:37.2 |
HIP 17034 |
34.34 |
| 2026-08-16 00:00 |
03:41:37.57 |
+24:39:39.3 |
HIP 17034 |
34.36 |
| 2026-08-16 12:00 |
03:41:37.67 |
+24:39:41.3 |
HIP 17034 |
34.38 |
| 2026-08-17 00:00 |
03:41:37.75 |
+24:39:43.3 |
HIP 17034 |
34.40 |
| 2026-08-17 12:00 |
03:41:37.81 |
+24:39:45.2 |
HIP 17034 |
34.41 |
| 2026-08-18 00:00 |
03:41:37.85 |
+24:39:47.1 |
HIP 17034 |
34.42 |
| 2026-08-18 12:00 |
03:41:37.88 |
+24:39:48.9 |
HIP 17034 |
34.42 |
| 2026-08-19 00:00 |
03:41:37.89 |
+24:39:50.6 |
HIP 17034 |
34.42 |