| 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) |
| 2026-03-26 00:00 |
07:55:06.22 |
-66:17:12.5 |
HIP 38645 |
4.88 |
| 2026-03-26 12:00 |
07:55:03.82 |
-66:16:39.4 |
HIP 38645 |
4.27 |
| 2026-03-27 00:00 |
07:55:01.46 |
-66:16:06.2 |
HIP 38645 |
3.67 |
| 2026-03-27 12:00 |
07:54:59.16 |
-66:15:32.9 |
HIP 38645 |
3.07 |
| 2026-03-28 00:00 |
07:54:56.91 |
-66:14:59.5 |
HIP 38645 |
2.47 |
| 2026-03-28 12:00 |
07:54:54.71 |
-66:14:26.0 |
HIP 38645 |
1.87 |
| 2026-03-29 00:00 |
07:54:52.55 |
-66:13:52.4 |
HIP 38645 |
1.27 |
| 2026-03-29 12:00 |
07:54:50.45 |
-66:13:18.7 |
HIP 38645 |
0.68 |
| 2026-03-30 00:00 |
07:54:48.40 |
-66:12:44.9 |
HIP 38645 |
0.16 |
| 2026-03-30 12:00 |
07:54:46.40 |
-66:12:11.0 |
HIP 38645 |
0.56 |
| 2026-03-31 00:00 |
07:54:44.45 |
-66:11:37.0 |
HIP 38645 |
1.15 |
| 2026-03-31 12:00 |
07:54:42.55 |
-66:11:03.0 |
HIP 38645 |
1.74 |
| 2026-04-01 00:00 |
07:54:40.71 |
-66:10:28.8 |
HIP 38645 |
2.34 |
| 2026-04-01 12:00 |
07:54:38.91 |
-66:09:54.6 |
HIP 38645 |
2.94 |
| 2026-04-02 00:00 |
07:54:37.16 |
-66:09:20.3 |
HIP 38645 |
3.54 |
| 2026-04-02 12:00 |
07:54:35.46 |
-66:08:45.9 |
HIP 38645 |
4.14 |
| 2026-04-03 00:00 |
07:54:33.82 |
-66:08:11.5 |
HIP 38645 |
4.73 |
| 2026-04-03 12:00 |
07:54:32.22 |
-66:07:36.9 |
HIP 38645 |
5.33 |
| 2026-04-04 00:00 |
07:54:30.68 |
-66:07:02.4 |
HIP 38645 |
5.93 |
| 2026-04-04 12:00 |
07:54:29.19 |
-66:06:27.7 |
HIP 38645 |
6.53 |
| 2026-04-05 00:00 |
07:54:27.74 |
-66:05:53.0 |
HIP 38645 |
7.12 |
| 2026-04-05 12:00 |
07:54:26.35 |
-66:05:18.2 |
HIP 38645 |
7.72 |
| 2026-04-06 00:00 |
07:54:25.01 |
-66:04:43.4 |
HIP 38645 |
8.32 |
| 2026-04-06 12:00 |
07:54:23.72 |
-66:04:08.5 |
HIP 38645 |
8.91 |
| 2026-04-07 00:00 |
07:54:22.48 |
-66:03:33.5 |
HIP 38645 |
9.51 |
| 2026-04-07 12:00 |
07:54:21.30 |
-66:02:58.6 |
HIP 38645 |
10.10 |
| 2026-04-08 00:00 |
07:54:20.16 |
-66:02:23.5 |
HIP 38645 |
10.69 |
| 2026-04-08 12:00 |
07:54:19.07 |
-66:01:48.4 |
HIP 38645 |
11.29 |
| 2026-04-09 00:00 |
07:54:18.04 |
-66:01:13.3 |
HIP 38645 |
11.88 |
| 2026-04-09 12:00 |
07:54:17.06 |
-66:00:38.2 |
HIP 38645 |
12.47 |
| 2026-04-10 00:00 |
07:54:16.12 |
-66:00:03.0 |
HIP 38645 |
13.07 |
| 2026-04-10 12:00 |
07:54:15.24 |
-65:59:27.7 |
HIP 38645 |
13.66 |
| 2026-04-11 00:00 |
07:54:14.41 |
-65:58:52.5 |
HIP 38645 |
14.25 |
| 2026-04-11 12:00 |
07:54:13.63 |
-65:58:17.2 |
HIP 38645 |
14.84 |
| 2026-04-12 00:00 |
07:54:12.90 |
-65:57:41.9 |
HIP 38645 |
15.43 |
| 2026-04-12 12:00 |
07:54:12.23 |
-65:57:06.5 |
HIP 38645 |
16.02 |
| 2026-04-13 00:00 |
07:54:11.60 |
-65:56:31.2 |
HIP 38645 |
16.61 |
| 2026-04-13 12:00 |
07:54:11.02 |
-65:55:55.8 |
HIP 38645 |
17.20 |
| 2026-04-14 00:00 |
07:54:10.50 |
-65:55:20.4 |
HIP 38645 |
17.79 |
| 2026-04-14 12:00 |
07:54:10.03 |
-65:54:45.0 |
HIP 38645 |
18.37 |
| 2026-04-15 00:00 |
07:54:09.60 |
-65:54:09.6 |
HIP 38645 |
18.96 |
| 2026-04-15 12:00 |
07:54:09.23 |
-65:53:34.2 |
HIP 38645 |
19.55 |
| 2026-04-16 00:00 |
07:54:08.91 |
-65:52:58.8 |
HIP 38645 |
20.13 |