| Parameter |
Value |
| Designation |
C/1998 M5 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1999-01-24T13:39:13.763520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:54Z |
| Obs used |
1238 |
| NEO |
- |
| M1 |
9.500 |
| K1 |
5.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-11-27.0000000 |
| e |
0.99602466 |
| q (au) |
1.742289 |
| a (au) |
438.273933 |
| i (deg) |
82.228882 |
| Ω (om, deg) |
333.376703 |
| ω (w, deg) |
101.282943 |
| M (ma, deg) |
359.993709 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.498 + 5.665\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.498 |
| n |
5.665 |
| gf |
1.000 |
| gb |
-0.954 |
| k |
0.996 |
| 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) |
| 2026-09-20 00:00 |
08:14:07.37 |
-65:19:23.5 |
HIP 40585 |
27.72 |
| 2026-09-20 12:00 |
08:14:10.31 |
-65:19:54.9 |
HIP 40585 |
27.13 |
| 2026-09-21 00:00 |
08:14:13.22 |
-65:20:26.5 |
HIP 40585 |
26.54 |
| 2026-09-21 12:00 |
08:14:16.09 |
-65:20:58.2 |
HIP 40585 |
25.96 |
| 2026-09-22 00:00 |
08:14:18.92 |
-65:21:30.1 |
HIP 40585 |
25.37 |
| 2026-09-22 12:00 |
08:14:21.71 |
-65:22:02.2 |
HIP 40585 |
24.79 |
| 2026-09-23 00:00 |
08:14:24.46 |
-65:22:34.4 |
HIP 40585 |
24.20 |
| 2026-09-23 12:00 |
08:14:27.18 |
-65:23:06.7 |
HIP 40585 |
23.63 |
| 2026-09-24 00:00 |
08:14:29.85 |
-65:23:39.2 |
HIP 40585 |
23.05 |
| 2026-09-24 12:00 |
08:14:32.48 |
-65:24:11.8 |
HIP 40585 |
22.48 |
| 2026-09-25 00:00 |
08:14:35.08 |
-65:24:44.6 |
HIP 40585 |
21.91 |
| 2026-09-25 12:00 |
08:14:37.63 |
-65:25:17.5 |
HIP 40585 |
21.34 |
| 2026-09-26 00:00 |
08:14:40.15 |
-65:25:50.6 |
HIP 40585 |
20.78 |
| 2026-09-26 12:00 |
08:14:42.62 |
-65:26:23.8 |
HIP 40585 |
20.23 |
| 2026-09-27 00:00 |
08:14:45.06 |
-65:26:57.1 |
HIP 40585 |
19.68 |
| 2026-09-27 12:00 |
08:14:47.45 |
-65:27:30.6 |
HIP 40585 |
19.13 |
| 2026-09-28 00:00 |
08:14:49.80 |
-65:28:04.2 |
HIP 40585 |
18.59 |
| 2026-09-28 12:00 |
08:14:52.11 |
-65:28:37.9 |
HIP 40585 |
18.06 |
| 2026-09-29 00:00 |
08:14:54.38 |
-65:29:11.8 |
HIP 40585 |
17.53 |
| 2026-09-29 12:00 |
08:14:56.61 |
-65:29:45.7 |
HIP 40585 |
17.02 |
| 2026-09-30 00:00 |
08:14:58.80 |
-65:30:19.8 |
HIP 40585 |
16.51 |
| 2026-09-30 12:00 |
08:15:00.94 |
-65:30:54.1 |
HIP 40585 |
16.01 |
| 2026-10-01 00:00 |
08:15:03.04 |
-65:31:28.4 |
HIP 40585 |
15.53 |
| 2026-10-01 12:00 |
08:15:05.10 |
-65:32:02.9 |
HIP 40585 |
15.05 |
| 2026-10-02 00:00 |
08:15:07.12 |
-65:32:37.4 |
HIP 40585 |
14.59 |
| 2026-10-02 12:00 |
08:15:09.09 |
-65:33:12.1 |
HIP 40585 |
14.15 |
| 2026-10-03 00:00 |
08:15:11.02 |
-65:33:46.9 |
HIP 40585 |
13.72 |
| 2026-10-03 12:00 |
08:15:12.90 |
-65:34:21.8 |
HIP 40585 |
13.30 |
| 2026-10-04 00:00 |
08:15:14.75 |
-65:34:56.8 |
HIP 40585 |
12.91 |
| 2026-10-04 12:00 |
08:15:16.54 |
-65:35:31.9 |
HIP 40585 |
12.54 |
| 2026-10-05 00:00 |
08:15:18.30 |
-65:36:07.2 |
HIP 40585 |
12.20 |
| 2026-10-05 12:00 |
08:15:20.01 |
-65:36:42.5 |
HIP 40585 |
11.88 |
| 2026-10-06 00:00 |
08:15:21.67 |
-65:37:17.9 |
HIP 40585 |
11.58 |
| 2026-10-06 12:00 |
08:15:23.29 |
-65:37:53.4 |
HIP 40585 |
11.32 |
| 2026-10-07 00:00 |
08:15:24.87 |
-65:38:29.0 |
HIP 40585 |
11.09 |
| 2026-10-07 12:00 |
08:15:26.40 |
-65:39:04.7 |
HIP 40585 |
10.90 |
| 2026-10-08 00:00 |
08:15:27.88 |
-65:39:40.5 |
HIP 40585 |
10.74 |
| 2026-10-08 12:00 |
08:15:29.32 |
-65:40:16.3 |
HIP 40585 |
10.62 |
| 2026-10-09 00:00 |
08:15:30.71 |
-65:40:52.3 |
HIP 40585 |
10.54 |
| 2026-10-09 12:00 |
08:15:32.05 |
-65:41:28.3 |
HIP 40585 |
10.50 |
| 2026-10-10 00:00 |
08:15:33.35 |
-65:42:04.4 |
HIP 40585 |
10.50 |
| 2026-10-10 12:00 |
08:15:34.60 |
-65:42:40.6 |
HIP 40585 |
10.55 |
| 2026-10-11 00:00 |
08:15:35.81 |
-65:43:16.8 |
HIP 40585 |
10.63 |