| 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
$$
M_a = (2.191 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
2.191 |
| n |
6.000 |
| gf |
0.933 |
| gb |
-0.858 |
| k |
1.000 |
| δ90 |
9.451 |
| 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 |
05:35:10.80 |
+41:51:58.9 |
HIP 26244 |
19.83 |
| 2026-09-20 12:00 |
05:35:10.49 |
+41:52:08.2 |
HIP 26244 |
20.00 |
| 2026-09-21 00:00 |
05:35:10.14 |
+41:52:17.6 |
HIP 26244 |
20.16 |
| 2026-09-21 12:00 |
05:35:09.77 |
+41:52:26.9 |
HIP 26244 |
20.32 |
| 2026-09-22 00:00 |
05:35:09.36 |
+41:52:36.1 |
HIP 26244 |
20.49 |
| 2026-09-22 12:00 |
05:35:08.93 |
+41:52:45.4 |
HIP 26244 |
20.65 |
| 2026-09-23 00:00 |
05:35:08.47 |
+41:52:54.6 |
HIP 26244 |
20.82 |
| 2026-09-23 12:00 |
05:35:07.98 |
+41:53:03.9 |
HIP 26244 |
20.98 |
| 2026-09-24 00:00 |
05:35:07.46 |
+41:53:13.1 |
HIP 26244 |
21.15 |
| 2026-09-24 12:00 |
05:35:06.91 |
+41:53:22.2 |
HIP 26244 |
21.32 |
| 2026-09-25 00:00 |
05:35:06.33 |
+41:53:31.4 |
HIP 26244 |
21.49 |
| 2026-09-25 12:00 |
05:35:05.73 |
+41:53:40.5 |
HIP 26244 |
21.66 |
| 2026-09-26 00:00 |
05:35:05.09 |
+41:53:49.6 |
HIP 26244 |
21.83 |
| 2026-09-26 12:00 |
05:35:04.43 |
+41:53:58.7 |
HIP 26057 |
21.77 |
| 2026-09-27 00:00 |
05:35:03.74 |
+41:54:07.8 |
HIP 26057 |
21.58 |
| 2026-09-27 12:00 |
05:35:03.02 |
+41:54:16.8 |
HIP 26057 |
21.38 |
| 2026-09-28 00:00 |
05:35:02.27 |
+41:54:25.8 |
HIP 26057 |
21.18 |
| 2026-09-28 12:00 |
05:35:01.49 |
+41:54:34.8 |
HIP 26057 |
20.98 |
| 2026-09-29 00:00 |
05:35:00.68 |
+41:54:43.7 |
HIP 26057 |
20.77 |
| 2026-09-29 12:00 |
05:34:59.85 |
+41:54:52.6 |
HIP 26057 |
20.56 |
| 2026-09-30 00:00 |
05:34:58.98 |
+41:55:01.5 |
HIP 26057 |
20.34 |
| 2026-09-30 12:00 |
05:34:58.09 |
+41:55:10.3 |
HIP 26057 |
20.12 |
| 2026-10-01 00:00 |
05:34:57.17 |
+41:55:19.1 |
HIP 26057 |
19.89 |
| 2026-10-01 12:00 |
05:34:56.22 |
+41:55:27.9 |
HIP 26057 |
19.67 |
| 2026-10-02 00:00 |
05:34:55.24 |
+41:55:36.6 |
HIP 26057 |
19.43 |
| 2026-10-02 12:00 |
05:34:54.23 |
+41:55:45.3 |
HIP 26057 |
19.20 |
| 2026-10-03 00:00 |
05:34:53.20 |
+41:55:54.0 |
HIP 26057 |
18.96 |
| 2026-10-03 12:00 |
05:34:52.13 |
+41:56:02.6 |
HIP 26057 |
18.71 |
| 2026-10-04 00:00 |
05:34:51.04 |
+41:56:11.2 |
HIP 26057 |
18.46 |
| 2026-10-04 12:00 |
05:34:49.92 |
+41:56:19.8 |
HIP 26057 |
18.21 |
| 2026-10-05 00:00 |
05:34:48.77 |
+41:56:28.3 |
HIP 26057 |
17.95 |
| 2026-10-05 12:00 |
05:34:47.59 |
+41:56:36.7 |
HIP 26057 |
17.69 |
| 2026-10-06 00:00 |
05:34:46.39 |
+41:56:45.2 |
HIP 26057 |
17.43 |
| 2026-10-06 12:00 |
05:34:45.15 |
+41:56:53.5 |
HIP 26057 |
17.16 |
| 2026-10-07 00:00 |
05:34:43.89 |
+41:57:01.9 |
HIP 26057 |
16.89 |
| 2026-10-07 12:00 |
05:34:42.60 |
+41:57:10.2 |
HIP 26057 |
16.61 |
| 2026-10-08 00:00 |
05:34:41.28 |
+41:57:18.4 |
HIP 26057 |
16.33 |
| 2026-10-08 12:00 |
05:34:39.93 |
+41:57:26.6 |
HIP 26057 |
16.05 |
| 2026-10-09 00:00 |
05:34:38.55 |
+41:57:34.7 |
HIP 26057 |
15.76 |
| 2026-10-09 12:00 |
05:34:37.15 |
+41:57:42.8 |
HIP 26057 |
15.47 |
| 2026-10-10 00:00 |
05:34:35.72 |
+41:57:50.9 |
HIP 26057 |
15.17 |
| 2026-10-10 12:00 |
05:34:34.26 |
+41:57:58.9 |
HIP 26057 |
14.88 |
| 2026-10-11 00:00 |
05:34:32.77 |
+41:58:06.8 |
HIP 26057 |
14.57 |