| Parameter |
Value |
| Designation |
C/1998 M6 (Montani) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1998-10-06T09:36:58.354560Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:57Z |
| Obs used |
94 |
| NEO |
- |
| M1 |
7.500 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-08-01.0000000 |
| e |
0.99887950 |
| q (au) |
5.978630 |
| a (au) |
5335.660755 |
| i (deg) |
91.539988 |
| Ω (om, deg) |
306.603673 |
| ω (w, deg) |
9.130637 |
| M (ma, deg) |
359.999832 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.338 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.338 |
| n |
6.000 |
| gf |
0.800 |
| gb |
-0.865 |
| k |
0.988 |
| δ90 |
1.326 |
| 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) |
| 2026-09-20 00:00 |
09:33:24.08 |
+48:48:00.6 |
HIP 46878 |
10.44 |
| 2026-09-20 12:00 |
09:33:26.84 |
+48:48:02.9 |
HIP 46878 |
10.51 |
| 2026-09-21 00:00 |
09:33:29.59 |
+48:48:05.4 |
HIP 46878 |
10.59 |
| 2026-09-21 12:00 |
09:33:32.31 |
+48:48:08.1 |
HIP 46981 |
10.21 |
| 2026-09-22 00:00 |
09:33:35.02 |
+48:48:11.0 |
HIP 46981 |
9.79 |
| 2026-09-22 12:00 |
09:33:37.71 |
+48:48:14.1 |
HIP 46981 |
9.39 |
| 2026-09-23 00:00 |
09:33:40.38 |
+48:48:17.4 |
HIP 46981 |
8.99 |
| 2026-09-23 12:00 |
09:33:43.03 |
+48:48:20.9 |
HIP 46981 |
8.60 |
| 2026-09-24 00:00 |
09:33:45.66 |
+48:48:24.6 |
HIP 46981 |
8.22 |
| 2026-09-24 12:00 |
09:33:48.27 |
+48:48:28.5 |
HIP 46981 |
7.85 |
| 2026-09-25 00:00 |
09:33:50.86 |
+48:48:32.5 |
HIP 46981 |
7.49 |
| 2026-09-25 12:00 |
09:33:53.44 |
+48:48:36.8 |
HIP 46981 |
7.14 |
| 2026-09-26 00:00 |
09:33:55.99 |
+48:48:41.2 |
HIP 46981 |
6.81 |
| 2026-09-26 12:00 |
09:33:58.53 |
+48:48:45.8 |
HIP 46981 |
6.49 |
| 2026-09-27 00:00 |
09:34:01.04 |
+48:48:50.7 |
HIP 46981 |
6.19 |
| 2026-09-27 12:00 |
09:34:03.54 |
+48:48:55.7 |
HIP 46981 |
5.91 |
| 2026-09-28 00:00 |
09:34:06.01 |
+48:49:00.9 |
HIP 46981 |
5.65 |
| 2026-09-28 12:00 |
09:34:08.46 |
+48:49:06.2 |
HIP 46981 |
5.42 |
| 2026-09-29 00:00 |
09:34:10.89 |
+48:49:11.8 |
HIP 46981 |
5.21 |
| 2026-09-29 12:00 |
09:34:13.31 |
+48:49:17.6 |
HIP 46981 |
5.04 |
| 2026-09-30 00:00 |
09:34:15.70 |
+48:49:23.5 |
HIP 46981 |
4.89 |
| 2026-09-30 12:00 |
09:34:18.06 |
+48:49:29.7 |
HIP 46981 |
4.78 |
| 2026-10-01 00:00 |
09:34:20.41 |
+48:49:36.0 |
HIP 46981 |
4.71 |
| 2026-10-01 12:00 |
09:34:22.74 |
+48:49:42.5 |
HIP 46981 |
4.67 |
| 2026-10-02 00:00 |
09:34:25.04 |
+48:49:49.2 |
HIP 46981 |
4.67 |
| 2026-10-02 12:00 |
09:34:27.32 |
+48:49:56.1 |
HIP 46981 |
4.71 |
| 2026-10-03 00:00 |
09:34:29.58 |
+48:50:03.1 |
HIP 46981 |
4.78 |
| 2026-10-03 12:00 |
09:34:31.82 |
+48:50:10.4 |
HIP 46981 |
4.89 |
| 2026-10-04 00:00 |
09:34:34.03 |
+48:50:17.8 |
HIP 46981 |
5.03 |
| 2026-10-04 12:00 |
09:34:36.22 |
+48:50:25.4 |
HIP 46981 |
5.19 |
| 2026-10-05 00:00 |
09:34:38.39 |
+48:50:33.3 |
HIP 46981 |
5.38 |
| 2026-10-05 12:00 |
09:34:40.54 |
+48:50:41.2 |
HIP 46981 |
5.59 |
| 2026-10-06 00:00 |
09:34:42.66 |
+48:50:49.4 |
HIP 46981 |
5.82 |
| 2026-10-06 12:00 |
09:34:44.75 |
+48:50:57.8 |
HIP 46981 |
6.07 |
| 2026-10-07 00:00 |
09:34:46.83 |
+48:51:06.3 |
HIP 46981 |
6.33 |
| 2026-10-07 12:00 |
09:34:48.88 |
+48:51:15.0 |
HIP 46981 |
6.60 |
| 2026-10-08 00:00 |
09:34:50.90 |
+48:51:24.0 |
HIP 46981 |
6.88 |
| 2026-10-08 12:00 |
09:34:52.90 |
+48:51:33.0 |
HIP 46981 |
7.17 |
| 2026-10-09 00:00 |
09:34:54.88 |
+48:51:42.3 |
HIP 46981 |
7.46 |
| 2026-10-09 12:00 |
09:34:56.83 |
+48:51:51.8 |
HIP 46981 |
7.77 |
| 2026-10-10 00:00 |
09:34:58.75 |
+48:52:01.4 |
HIP 46981 |
8.07 |
| 2026-10-10 12:00 |
09:35:00.66 |
+48:52:11.2 |
HIP 46981 |
8.38 |
| 2026-10-11 00:00 |
09:35:02.53 |
+48:52:21.2 |
HIP 46981 |
8.70 |