| Parameter |
Value |
| Designation |
C/1998 M4 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1997-12-10T02:48:12.064320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:53Z |
| Obs used |
116 |
| NEO |
- |
| M1 |
9.500 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-07-03.0000000 |
| e |
0.99738677 |
| q (au) |
2.600017 |
| a (au) |
994.943592 |
| i (deg) |
154.571097 |
| Ω (om, deg) |
92.922669 |
| ω (w, deg) |
106.286301 |
| M (ma, deg) |
0.006434 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.999 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.999 |
| n |
2.000 |
| gf |
0.812 |
| gb |
-0.935 |
| k |
1.000 |
| δ90 |
2.369 |
| 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 |
12:07:10.03 |
-27:44:04.0 |
HIP 59006 |
31.38 |
| 2026-09-20 12:00 |
12:07:12.31 |
-27:44:14.6 |
HIP 59006 |
31.80 |
| 2026-09-21 00:00 |
12:07:14.59 |
-27:44:25.4 |
HIP 59259 |
31.46 |
| 2026-09-21 12:00 |
12:07:16.88 |
-27:44:36.3 |
HIP 59259 |
30.93 |
| 2026-09-22 00:00 |
12:07:19.16 |
-27:44:47.3 |
HIP 59259 |
30.40 |
| 2026-09-22 12:00 |
12:07:21.45 |
-27:44:58.5 |
HIP 59259 |
29.86 |
| 2026-09-23 00:00 |
12:07:23.74 |
-27:45:09.8 |
HIP 59259 |
29.33 |
| 2026-09-23 12:00 |
12:07:26.03 |
-27:45:21.2 |
HIP 59259 |
28.79 |
| 2026-09-24 00:00 |
12:07:28.31 |
-27:45:32.8 |
HIP 59259 |
28.25 |
| 2026-09-24 12:00 |
12:07:30.60 |
-27:45:44.5 |
HIP 59259 |
27.72 |
| 2026-09-25 00:00 |
12:07:32.89 |
-27:45:56.4 |
HIP 59259 |
27.18 |
| 2026-09-25 12:00 |
12:07:35.18 |
-27:46:08.3 |
HIP 59259 |
26.64 |
| 2026-09-26 00:00 |
12:07:37.47 |
-27:46:20.4 |
HIP 59259 |
26.10 |
| 2026-09-26 12:00 |
12:07:39.76 |
-27:46:32.7 |
HIP 59259 |
25.55 |
| 2026-09-27 00:00 |
12:07:42.04 |
-27:46:45.0 |
HIP 59259 |
25.01 |
| 2026-09-27 12:00 |
12:07:44.33 |
-27:46:57.5 |
HIP 59259 |
24.47 |
| 2026-09-28 00:00 |
12:07:46.62 |
-27:47:10.1 |
HIP 59259 |
23.93 |
| 2026-09-28 12:00 |
12:07:48.90 |
-27:47:22.9 |
HIP 59259 |
23.38 |
| 2026-09-29 00:00 |
12:07:51.19 |
-27:47:35.7 |
HIP 59259 |
22.84 |
| 2026-09-29 12:00 |
12:07:53.47 |
-27:47:48.7 |
HIP 59259 |
22.29 |
| 2026-09-30 00:00 |
12:07:55.75 |
-27:48:01.8 |
HIP 59259 |
21.74 |
| 2026-09-30 12:00 |
12:07:58.03 |
-27:48:15.1 |
HIP 59259 |
21.20 |
| 2026-10-01 00:00 |
12:08:00.31 |
-27:48:28.4 |
HIP 59259 |
20.65 |
| 2026-10-01 12:00 |
12:08:02.59 |
-27:48:41.9 |
HIP 59259 |
20.10 |
| 2026-10-02 00:00 |
12:08:04.86 |
-27:48:55.5 |
HIP 59259 |
19.55 |
| 2026-10-02 12:00 |
12:08:07.13 |
-27:49:09.3 |
HIP 59259 |
19.01 |
| 2026-10-03 00:00 |
12:08:09.40 |
-27:49:23.1 |
HIP 59259 |
18.46 |
| 2026-10-03 12:00 |
12:08:11.67 |
-27:49:37.1 |
HIP 59259 |
17.91 |
| 2026-10-04 00:00 |
12:08:13.94 |
-27:49:51.1 |
HIP 59259 |
17.36 |
| 2026-10-04 12:00 |
12:08:16.20 |
-27:50:05.3 |
HIP 59259 |
16.81 |
| 2026-10-05 00:00 |
12:08:18.46 |
-27:50:19.6 |
HIP 59259 |
16.26 |
| 2026-10-05 12:00 |
12:08:20.71 |
-27:50:34.1 |
HIP 59259 |
15.71 |
| 2026-10-06 00:00 |
12:08:22.96 |
-27:50:48.6 |
HIP 59259 |
15.16 |
| 2026-10-06 12:00 |
12:08:25.21 |
-27:51:03.3 |
HIP 59259 |
14.61 |
| 2026-10-07 00:00 |
12:08:27.46 |
-27:51:18.0 |
HIP 59259 |
14.06 |
| 2026-10-07 12:00 |
12:08:29.70 |
-27:51:32.9 |
HIP 59259 |
13.51 |
| 2026-10-08 00:00 |
12:08:31.94 |
-27:51:47.9 |
HIP 59259 |
12.96 |
| 2026-10-08 12:00 |
12:08:34.17 |
-27:52:03.0 |
HIP 59259 |
12.41 |
| 2026-10-09 00:00 |
12:08:36.40 |
-27:52:18.2 |
HIP 59259 |
11.86 |
| 2026-10-09 12:00 |
12:08:38.62 |
-27:52:33.5 |
HIP 59259 |
11.31 |
| 2026-10-10 00:00 |
12:08:40.84 |
-27:52:48.9 |
HIP 59259 |
10.76 |
| 2026-10-10 12:00 |
12:08:43.06 |
-27:53:04.4 |
HIP 59259 |
10.21 |
| 2026-10-11 00:00 |
12:08:45.27 |
-27:53:20.0 |
HIP 59259 |
9.66 |