| 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) |
| 2026-05-12 00:00 |
12:04:23.63 |
-28:22:39.4 |
HIP 58759 |
19.27 |
| 2026-05-12 12:00 |
12:04:21.89 |
-28:22:17.8 |
HIP 58759 |
18.78 |
| 2026-05-13 00:00 |
12:04:20.17 |
-28:21:56.2 |
HIP 58759 |
18.30 |
| 2026-05-13 12:00 |
12:04:18.46 |
-28:21:34.6 |
HIP 58759 |
17.82 |
| 2026-05-14 00:00 |
12:04:16.77 |
-28:21:13.0 |
HIP 58759 |
17.35 |
| 2026-05-14 12:00 |
12:04:15.09 |
-28:20:51.3 |
HIP 58759 |
16.88 |
| 2026-05-15 00:00 |
12:04:13.44 |
-28:20:29.7 |
HIP 58759 |
16.43 |
| 2026-05-15 12:00 |
12:04:11.80 |
-28:20:08.1 |
HIP 58759 |
15.98 |
| 2026-05-16 00:00 |
12:04:10.18 |
-28:19:46.5 |
HIP 58759 |
15.53 |
| 2026-05-16 12:00 |
12:04:08.58 |
-28:19:24.9 |
HIP 58759 |
15.10 |
| 2026-05-17 00:00 |
12:04:06.99 |
-28:19:03.3 |
HIP 58759 |
14.67 |
| 2026-05-17 12:00 |
12:04:05.43 |
-28:18:41.7 |
HIP 58759 |
14.25 |
| 2026-05-18 00:00 |
12:04:03.88 |
-28:18:20.1 |
HIP 58759 |
13.84 |
| 2026-05-18 12:00 |
12:04:02.35 |
-28:17:58.5 |
HIP 58759 |
13.44 |
| 2026-05-19 00:00 |
12:04:00.83 |
-28:17:37.0 |
HIP 58759 |
13.05 |
| 2026-05-19 12:00 |
12:03:59.34 |
-28:17:15.4 |
HIP 58759 |
12.67 |
| 2026-05-20 00:00 |
12:03:57.86 |
-28:16:53.9 |
HIP 58759 |
12.31 |
| 2026-05-20 12:00 |
12:03:56.41 |
-28:16:32.4 |
HIP 58759 |
11.95 |
| 2026-05-21 00:00 |
12:03:54.97 |
-28:16:11.0 |
HIP 58759 |
11.61 |
| 2026-05-21 12:00 |
12:03:53.55 |
-28:15:49.5 |
HIP 58759 |
11.28 |
| 2026-05-22 00:00 |
12:03:52.15 |
-28:15:28.1 |
HIP 58759 |
10.97 |
| 2026-05-22 12:00 |
12:03:50.77 |
-28:15:06.7 |
HIP 58759 |
10.68 |
| 2026-05-23 00:00 |
12:03:49.40 |
-28:14:45.3 |
HIP 58759 |
10.40 |
| 2026-05-23 12:00 |
12:03:48.06 |
-28:14:24.0 |
HIP 58759 |
10.13 |
| 2026-05-24 00:00 |
12:03:46.74 |
-28:14:02.7 |
HIP 58759 |
9.89 |
| 2026-05-24 12:00 |
12:03:45.43 |
-28:13:41.4 |
HIP 58759 |
9.67 |
| 2026-05-25 00:00 |
12:03:44.14 |
-28:13:20.2 |
HIP 58759 |
9.46 |
| 2026-05-25 12:00 |
12:03:42.88 |
-28:12:59.0 |
HIP 58759 |
9.28 |
| 2026-05-26 00:00 |
12:03:41.63 |
-28:12:37.8 |
HIP 58759 |
9.13 |
| 2026-05-26 12:00 |
12:03:40.40 |
-28:12:16.7 |
HIP 58759 |
8.99 |
| 2026-05-27 00:00 |
12:03:39.19 |
-28:11:55.6 |
HIP 58759 |
8.88 |
| 2026-05-27 12:00 |
12:03:38.00 |
-28:11:34.5 |
HIP 58759 |
8.79 |
| 2026-05-28 00:00 |
12:03:36.83 |
-28:11:13.5 |
HIP 58759 |
8.73 |
| 2026-05-28 12:00 |
12:03:35.68 |
-28:10:52.6 |
HIP 58759 |
8.69 |
| 2026-05-29 00:00 |
12:03:34.55 |
-28:10:31.7 |
HIP 58759 |
8.68 |
| 2026-05-29 12:00 |
12:03:33.44 |
-28:10:10.8 |
HIP 58759 |
8.69 |
| 2026-05-30 00:00 |
12:03:32.34 |
-28:09:50.0 |
HIP 58759 |
8.72 |
| 2026-05-30 12:00 |
12:03:31.27 |
-28:09:29.2 |
HIP 58759 |
8.78 |
| 2026-05-31 00:00 |
12:03:30.22 |
-28:09:08.5 |
HIP 58759 |
8.85 |
| 2026-05-31 12:00 |
12:03:29.19 |
-28:08:47.8 |
HIP 58759 |
8.95 |
| 2026-06-01 00:00 |
12:03:28.17 |
-28:08:27.2 |
HIP 58759 |
9.07 |
| 2026-06-01 12:00 |
12:03:27.18 |
-28:08:06.6 |
HIP 58759 |
9.21 |
| 2026-06-02 00:00 |
12:03:26.21 |
-28:07:46.1 |
HIP 58759 |
9.36 |