| 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
$$
M_a = (11.003 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.003 |
| n |
2.000 |
| gf |
0.812 |
| gb |
-0.935 |
| k |
1.000 |
| δ90 |
2.331 |
| 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 |
12:08:03.23 |
-28:52:21.0 |
HIP 59140 |
12.79 |
| 2026-03-26 12:00 |
12:08:00.56 |
-28:52:06.8 |
HIP 59140 |
12.76 |
| 2026-03-27 00:00 |
12:07:57.88 |
-28:51:52.5 |
HIP 59140 |
12.75 |
| 2026-03-27 12:00 |
12:07:55.21 |
-28:51:38.1 |
HIP 59140 |
12.78 |
| 2026-03-28 00:00 |
12:07:52.54 |
-28:51:23.5 |
HIP 59140 |
12.84 |
| 2026-03-28 12:00 |
12:07:49.87 |
-28:51:08.7 |
HIP 59140 |
12.94 |
| 2026-03-29 00:00 |
12:07:47.21 |
-28:50:53.9 |
HIP 59140 |
13.07 |
| 2026-03-29 12:00 |
12:07:44.54 |
-28:50:38.9 |
HIP 59140 |
13.23 |
| 2026-03-30 00:00 |
12:07:41.88 |
-28:50:23.7 |
HIP 59140 |
13.42 |
| 2026-03-30 12:00 |
12:07:39.22 |
-28:50:08.4 |
HIP 59140 |
13.64 |
| 2026-03-31 00:00 |
12:07:36.57 |
-28:49:53.0 |
HIP 59140 |
13.88 |
| 2026-03-31 12:00 |
12:07:33.92 |
-28:49:37.5 |
HIP 59140 |
14.16 |
| 2026-04-01 00:00 |
12:07:31.27 |
-28:49:21.8 |
HIP 59140 |
14.45 |
| 2026-04-01 12:00 |
12:07:28.63 |
-28:49:06.0 |
HIP 59140 |
14.78 |
| 2026-04-02 00:00 |
12:07:25.99 |
-28:48:50.0 |
HIP 59140 |
15.12 |
| 2026-04-02 12:00 |
12:07:23.36 |
-28:48:34.0 |
HIP 59140 |
15.48 |
| 2026-04-03 00:00 |
12:07:20.72 |
-28:48:17.8 |
HIP 59140 |
15.87 |
| 2026-04-03 12:00 |
12:07:18.10 |
-28:48:01.4 |
HIP 59140 |
16.27 |
| 2026-04-04 00:00 |
12:07:15.48 |
-28:47:45.0 |
HIP 59140 |
16.68 |
| 2026-04-04 12:00 |
12:07:12.86 |
-28:47:28.4 |
HIP 59140 |
17.12 |
| 2026-04-05 00:00 |
12:07:10.25 |
-28:47:11.7 |
HIP 59140 |
17.56 |
| 2026-04-05 12:00 |
12:07:07.64 |
-28:46:54.9 |
HIP 59140 |
18.02 |
| 2026-04-06 00:00 |
12:07:05.04 |
-28:46:38.0 |
HIP 59140 |
18.49 |
| 2026-04-06 12:00 |
12:07:02.44 |
-28:46:20.9 |
HIP 59140 |
18.97 |
| 2026-04-07 00:00 |
12:06:59.85 |
-28:46:03.8 |
HIP 59140 |
19.47 |
| 2026-04-07 12:00 |
12:06:57.27 |
-28:45:46.5 |
HIP 59140 |
19.97 |
| 2026-04-08 00:00 |
12:06:54.69 |
-28:45:29.1 |
HIP 59140 |
20.48 |
| 2026-04-08 12:00 |
12:06:52.12 |
-28:45:11.6 |
HIP 59140 |
20.99 |
| 2026-04-09 00:00 |
12:06:49.56 |
-28:44:53.9 |
HIP 58950 |
21.19 |
| 2026-04-09 12:00 |
12:06:47.00 |
-28:44:36.2 |
HIP 58950 |
20.61 |
| 2026-04-10 00:00 |
12:06:44.45 |
-28:44:18.4 |
HIP 58950 |
20.03 |
| 2026-04-10 12:00 |
12:06:41.90 |
-28:44:00.4 |
HIP 58950 |
19.46 |
| 2026-04-11 00:00 |
12:06:39.37 |
-28:43:42.3 |
HIP 58950 |
18.89 |
| 2026-04-11 12:00 |
12:06:36.84 |
-28:43:24.2 |
HIP 58950 |
18.33 |
| 2026-04-12 00:00 |
12:06:34.32 |
-28:43:05.9 |
HIP 58950 |
17.77 |
| 2026-04-12 12:00 |
12:06:31.80 |
-28:42:47.5 |
HIP 58950 |
17.22 |
| 2026-04-13 00:00 |
12:06:29.30 |
-28:42:29.1 |
HIP 58950 |
16.68 |
| 2026-04-13 12:00 |
12:06:26.80 |
-28:42:10.5 |
HIP 58950 |
16.14 |
| 2026-04-14 00:00 |
12:06:24.31 |
-28:41:51.8 |
HIP 58950 |
15.62 |
| 2026-04-14 12:00 |
12:06:21.83 |
-28:41:33.1 |
HIP 58950 |
15.10 |
| 2026-04-15 00:00 |
12:06:19.36 |
-28:41:14.2 |
HIP 58950 |
14.59 |
| 2026-04-15 12:00 |
12:06:16.89 |
-28:40:55.2 |
HIP 58950 |
14.10 |
| 2026-04-16 00:00 |
12:06:14.44 |
-28:40:36.2 |
HIP 58950 |
13.62 |