| 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
$$
M_a = (5.320 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.320 |
| n |
6.000 |
| gf |
0.800 |
| gb |
-0.865 |
| k |
0.989 |
| δ90 |
1.417 |
| 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) |
| 2026-03-26 00:00 |
09:24:33.18 |
+50:33:04.2 |
HIP 46156 |
16.51 |
| 2026-03-26 12:00 |
09:24:30.33 |
+50:32:52.1 |
HIP 46156 |
16.37 |
| 2026-03-27 00:00 |
09:24:27.51 |
+50:32:39.8 |
HIP 46156 |
16.24 |
| 2026-03-27 12:00 |
09:24:24.72 |
+50:32:27.3 |
HIP 46156 |
16.13 |
| 2026-03-28 00:00 |
09:24:21.95 |
+50:32:14.6 |
HIP 46156 |
16.02 |
| 2026-03-28 12:00 |
09:24:19.21 |
+50:32:01.7 |
HIP 46156 |
15.93 |
| 2026-03-29 00:00 |
09:24:16.49 |
+50:31:48.7 |
HIP 46156 |
15.84 |
| 2026-03-29 12:00 |
09:24:13.81 |
+50:31:35.4 |
HIP 45983 |
15.65 |
| 2026-03-30 00:00 |
09:24:11.15 |
+50:31:21.9 |
HIP 45983 |
15.32 |
| 2026-03-30 12:00 |
09:24:08.51 |
+50:31:08.3 |
HIP 45983 |
15.00 |
| 2026-03-31 00:00 |
09:24:05.91 |
+50:30:54.5 |
HIP 45983 |
14.69 |
| 2026-03-31 12:00 |
09:24:03.33 |
+50:30:40.5 |
HIP 45983 |
14.40 |
| 2026-04-01 00:00 |
09:24:00.78 |
+50:30:26.3 |
HIP 45983 |
14.12 |
| 2026-04-01 12:00 |
09:23:58.25 |
+50:30:11.9 |
HIP 45983 |
13.86 |
| 2026-04-02 00:00 |
09:23:55.76 |
+50:29:57.3 |
HIP 45983 |
13.62 |
| 2026-04-02 12:00 |
09:23:53.29 |
+50:29:42.6 |
HIP 45983 |
13.39 |
| 2026-04-03 00:00 |
09:23:50.85 |
+50:29:27.7 |
HIP 45983 |
13.18 |
| 2026-04-03 12:00 |
09:23:48.44 |
+50:29:12.6 |
HIP 45983 |
12.99 |
| 2026-04-04 00:00 |
09:23:46.06 |
+50:28:57.3 |
HIP 45983 |
12.81 |
| 2026-04-04 12:00 |
09:23:43.71 |
+50:28:41.9 |
HIP 45983 |
12.66 |
| 2026-04-05 00:00 |
09:23:41.38 |
+50:28:26.2 |
HIP 45983 |
12.52 |
| 2026-04-05 12:00 |
09:23:39.09 |
+50:28:10.4 |
HIP 45983 |
12.41 |
| 2026-04-06 00:00 |
09:23:36.82 |
+50:27:54.4 |
HIP 45983 |
12.32 |
| 2026-04-06 12:00 |
09:23:34.59 |
+50:27:38.3 |
HIP 45983 |
12.24 |
| 2026-04-07 00:00 |
09:23:32.38 |
+50:27:22.0 |
HIP 45983 |
12.19 |
| 2026-04-07 12:00 |
09:23:30.20 |
+50:27:05.5 |
HIP 45983 |
12.16 |
| 2026-04-08 00:00 |
09:23:28.05 |
+50:26:48.8 |
HIP 45983 |
12.16 |
| 2026-04-08 12:00 |
09:23:25.93 |
+50:26:32.0 |
HIP 45983 |
12.17 |
| 2026-04-09 00:00 |
09:23:23.84 |
+50:26:15.0 |
HIP 45983 |
12.20 |
| 2026-04-09 12:00 |
09:23:21.78 |
+50:25:57.9 |
HIP 45983 |
12.25 |
| 2026-04-10 00:00 |
09:23:19.75 |
+50:25:40.6 |
HIP 45983 |
12.33 |
| 2026-04-10 12:00 |
09:23:17.76 |
+50:25:23.1 |
HIP 45983 |
12.42 |
| 2026-04-11 00:00 |
09:23:15.79 |
+50:25:05.5 |
HIP 45983 |
12.53 |
| 2026-04-11 12:00 |
09:23:13.85 |
+50:24:47.7 |
HIP 45983 |
12.66 |
| 2026-04-12 00:00 |
09:23:11.94 |
+50:24:29.7 |
HIP 45983 |
12.81 |
| 2026-04-12 12:00 |
09:23:10.07 |
+50:24:11.6 |
HIP 45983 |
12.97 |
| 2026-04-13 00:00 |
09:23:08.22 |
+50:23:53.3 |
HIP 45983 |
13.15 |
| 2026-04-13 12:00 |
09:23:06.41 |
+50:23:34.9 |
HIP 45983 |
13.34 |
| 2026-04-14 00:00 |
09:23:04.62 |
+50:23:16.3 |
HIP 45983 |
13.55 |
| 2026-04-14 12:00 |
09:23:02.87 |
+50:22:57.6 |
HIP 45983 |
13.77 |
| 2026-04-15 00:00 |
09:23:01.15 |
+50:22:38.7 |
HIP 45983 |
14.01 |
| 2026-04-15 12:00 |
09:22:59.46 |
+50:22:19.7 |
HIP 45983 |
14.25 |
| 2026-04-16 00:00 |
09:22:57.80 |
+50:22:00.5 |
HIP 45983 |
14.51 |