| Parameter |
Value |
| Designation |
C/1998 M3 (Larsen) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1998-07-17T02:37:10.369920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:53Z |
| Obs used |
109 |
| NEO |
- |
| M1 |
6.500 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-08-29.0000000 |
| e |
1.00229380 |
| q (au) |
5.768232 |
| a (au) |
-2514.702905 |
| i (deg) |
113.422897 |
| Ω (om, deg) |
255.526698 |
| ω (w, deg) |
20.838100 |
| M (ma, deg) |
0.000335 |
Magnitude
Scatter + Global Linear
$$
M_a = (2.182 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
2.182 |
| n |
6.000 |
| gf |
0.963 |
| gb |
-1.000 |
| k |
1.000 |
| 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 |
05:22:42.32 |
+41:53:18.0 |
HIP 25048 |
11.23 |
| 2026-03-26 12:00 |
05:22:43.01 |
+41:53:03.9 |
HIP 25048 |
11.24 |
| 2026-03-27 00:00 |
05:22:43.72 |
+41:52:50.0 |
HIP 25048 |
11.26 |
| 2026-03-27 12:00 |
05:22:44.47 |
+41:52:36.0 |
HIP 25048 |
11.30 |
| 2026-03-28 00:00 |
05:22:45.24 |
+41:52:22.1 |
HIP 25048 |
11.35 |
| 2026-03-28 12:00 |
05:22:46.04 |
+41:52:08.3 |
HIP 25048 |
11.41 |
| 2026-03-29 00:00 |
05:22:46.87 |
+41:51:54.6 |
HIP 25048 |
11.48 |
| 2026-03-29 12:00 |
05:22:47.72 |
+41:51:40.8 |
HIP 25048 |
11.56 |
| 2026-03-30 00:00 |
05:22:48.61 |
+41:51:27.2 |
HIP 25048 |
11.65 |
| 2026-03-30 12:00 |
05:22:49.52 |
+41:51:13.6 |
HIP 25048 |
11.76 |
| 2026-03-31 00:00 |
05:22:50.45 |
+41:51:00.0 |
HIP 25048 |
11.87 |
| 2026-03-31 12:00 |
05:22:51.42 |
+41:50:46.5 |
HIP 25048 |
12.00 |
| 2026-04-01 00:00 |
05:22:52.41 |
+41:50:33.1 |
HIP 25048 |
12.14 |
| 2026-04-01 12:00 |
05:22:53.43 |
+41:50:19.7 |
HIP 25048 |
12.29 |
| 2026-04-02 00:00 |
05:22:54.47 |
+41:50:06.4 |
HIP 25048 |
12.44 |
| 2026-04-02 12:00 |
05:22:55.54 |
+41:49:53.2 |
HIP 25048 |
12.61 |
| 2026-04-03 00:00 |
05:22:56.64 |
+41:49:40.0 |
HIP 25048 |
12.79 |
| 2026-04-03 12:00 |
05:22:57.77 |
+41:49:26.8 |
HIP 25048 |
12.98 |
| 2026-04-04 00:00 |
05:22:58.92 |
+41:49:13.8 |
HIP 25048 |
13.17 |
| 2026-04-04 12:00 |
05:23:00.09 |
+41:49:00.8 |
HIP 25048 |
13.38 |
| 2026-04-05 00:00 |
05:23:01.30 |
+41:48:47.8 |
HIP 25048 |
13.59 |
| 2026-04-05 12:00 |
05:23:02.53 |
+41:48:34.9 |
HIP 25048 |
13.82 |
| 2026-04-06 00:00 |
05:23:03.78 |
+41:48:22.1 |
HIP 25211 |
13.68 |
| 2026-04-06 12:00 |
05:23:05.06 |
+41:48:09.3 |
HIP 25211 |
13.38 |
| 2026-04-07 00:00 |
05:23:06.37 |
+41:47:56.7 |
HIP 25211 |
13.09 |
| 2026-04-07 12:00 |
05:23:07.70 |
+41:47:44.0 |
HIP 25211 |
12.79 |
| 2026-04-08 00:00 |
05:23:09.06 |
+41:47:31.5 |
HIP 25211 |
12.50 |
| 2026-04-08 12:00 |
05:23:10.44 |
+41:47:19.0 |
HIP 25211 |
12.20 |
| 2026-04-09 00:00 |
05:23:11.85 |
+41:47:06.6 |
HIP 25211 |
11.91 |
| 2026-04-09 12:00 |
05:23:13.29 |
+41:46:54.2 |
HIP 25211 |
11.62 |
| 2026-04-10 00:00 |
05:23:14.75 |
+41:46:41.9 |
HIP 25211 |
11.33 |
| 2026-04-10 12:00 |
05:23:16.23 |
+41:46:29.7 |
HIP 25211 |
11.05 |
| 2026-04-11 00:00 |
05:23:17.74 |
+41:46:17.6 |
HIP 25211 |
10.76 |
| 2026-04-11 12:00 |
05:23:19.27 |
+41:46:05.5 |
HIP 25211 |
10.49 |
| 2026-04-12 00:00 |
05:23:20.83 |
+41:45:53.5 |
HIP 25211 |
10.21 |
| 2026-04-12 12:00 |
05:23:22.41 |
+41:45:41.6 |
HIP 25211 |
9.94 |
| 2026-04-13 00:00 |
05:23:24.02 |
+41:45:29.7 |
HIP 25211 |
9.68 |
| 2026-04-13 12:00 |
05:23:25.65 |
+41:45:17.9 |
HIP 25211 |
9.42 |
| 2026-04-14 00:00 |
05:23:27.30 |
+41:45:06.2 |
HIP 25211 |
9.17 |
| 2026-04-14 12:00 |
05:23:28.98 |
+41:44:54.6 |
HIP 25211 |
8.93 |
| 2026-04-15 00:00 |
05:23:30.68 |
+41:44:43.0 |
HIP 25211 |
8.69 |
| 2026-04-15 12:00 |
05:23:32.40 |
+41:44:31.5 |
HIP 25211 |
8.47 |
| 2026-04-16 00:00 |
05:23:34.15 |
+41:44:20.1 |
HIP 25211 |
8.26 |