| 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) |
| 2026-07-29 00:00 |
05:33:12.70 |
+41:36:48.4 |
HIP 26244 |
25.42 |
| 2026-07-29 12:00 |
05:33:15.02 |
+41:36:54.9 |
HIP 26244 |
25.02 |
| 2026-07-30 00:00 |
05:33:17.32 |
+41:37:01.4 |
HIP 26244 |
24.61 |
| 2026-07-30 12:00 |
05:33:19.61 |
+41:37:08.1 |
HIP 26244 |
24.21 |
| 2026-07-31 00:00 |
05:33:21.88 |
+41:37:14.7 |
HIP 26244 |
23.82 |
| 2026-07-31 12:00 |
05:33:24.12 |
+41:37:21.5 |
HIP 26244 |
23.43 |
| 2026-08-01 00:00 |
05:33:26.35 |
+41:37:28.3 |
HIP 26244 |
23.05 |
| 2026-08-01 12:00 |
05:33:28.57 |
+41:37:35.2 |
HIP 26244 |
22.67 |
| 2026-08-02 00:00 |
05:33:30.76 |
+41:37:42.1 |
HIP 26244 |
22.30 |
| 2026-08-02 12:00 |
05:33:32.93 |
+41:37:49.1 |
HIP 26244 |
21.93 |
| 2026-08-03 00:00 |
05:33:35.09 |
+41:37:56.1 |
HIP 26244 |
21.57 |
| 2026-08-03 12:00 |
05:33:37.22 |
+41:38:03.2 |
HIP 26244 |
21.22 |
| 2026-08-04 00:00 |
05:33:39.34 |
+41:38:10.3 |
HIP 26244 |
20.87 |
| 2026-08-04 12:00 |
05:33:41.43 |
+41:38:17.5 |
HIP 26244 |
20.53 |
| 2026-08-05 00:00 |
05:33:43.51 |
+41:38:24.8 |
HIP 26244 |
20.19 |
| 2026-08-05 12:00 |
05:33:45.56 |
+41:38:32.1 |
HIP 26244 |
19.87 |
| 2026-08-06 00:00 |
05:33:47.60 |
+41:38:39.5 |
HIP 26244 |
19.54 |
| 2026-08-06 12:00 |
05:33:49.61 |
+41:38:46.9 |
HIP 26244 |
19.23 |
| 2026-08-07 00:00 |
05:33:51.60 |
+41:38:54.4 |
HIP 26244 |
18.92 |
| 2026-08-07 12:00 |
05:33:53.58 |
+41:39:01.9 |
HIP 26244 |
18.62 |
| 2026-08-08 00:00 |
05:33:55.53 |
+41:39:09.5 |
HIP 26244 |
18.32 |
| 2026-08-08 12:00 |
05:33:57.46 |
+41:39:17.1 |
HIP 26244 |
18.04 |
| 2026-08-09 00:00 |
05:33:59.37 |
+41:39:24.8 |
HIP 26244 |
17.76 |
| 2026-08-09 12:00 |
05:34:01.26 |
+41:39:32.5 |
HIP 26244 |
17.49 |
| 2026-08-10 00:00 |
05:34:03.12 |
+41:39:40.3 |
HIP 26244 |
17.22 |
| 2026-08-10 12:00 |
05:34:04.97 |
+41:39:48.1 |
HIP 26244 |
16.97 |
| 2026-08-11 00:00 |
05:34:06.79 |
+41:39:56.0 |
HIP 26244 |
16.72 |
| 2026-08-11 12:00 |
05:34:08.59 |
+41:40:04.0 |
HIP 26244 |
16.48 |
| 2026-08-12 00:00 |
05:34:10.37 |
+41:40:11.9 |
HIP 26244 |
16.25 |
| 2026-08-12 12:00 |
05:34:12.12 |
+41:40:19.9 |
HIP 26244 |
16.03 |
| 2026-08-13 00:00 |
05:34:13.85 |
+41:40:28.0 |
HIP 26244 |
15.82 |
| 2026-08-13 12:00 |
05:34:15.56 |
+41:40:36.1 |
HIP 26244 |
15.62 |
| 2026-08-14 00:00 |
05:34:17.25 |
+41:40:44.3 |
HIP 26244 |
15.42 |
| 2026-08-14 12:00 |
05:34:18.91 |
+41:40:52.5 |
HIP 26244 |
15.24 |
| 2026-08-15 00:00 |
05:34:20.55 |
+41:41:00.7 |
HIP 26244 |
15.06 |
| 2026-08-15 12:00 |
05:34:22.17 |
+41:41:09.0 |
HIP 26244 |
14.90 |
| 2026-08-16 00:00 |
05:34:23.76 |
+41:41:17.3 |
HIP 26244 |
14.74 |
| 2026-08-16 12:00 |
05:34:25.33 |
+41:41:25.7 |
HIP 26244 |
14.60 |
| 2026-08-17 00:00 |
05:34:26.88 |
+41:41:34.1 |
HIP 26244 |
14.46 |
| 2026-08-17 12:00 |
05:34:28.40 |
+41:41:42.5 |
HIP 26244 |
14.33 |
| 2026-08-18 00:00 |
05:34:29.90 |
+41:41:51.0 |
HIP 26244 |
14.21 |
| 2026-08-18 12:00 |
05:34:31.37 |
+41:41:59.5 |
HIP 26244 |
14.11 |
| 2026-08-19 00:00 |
05:34:32.82 |
+41:42:08.1 |
HIP 26244 |
14.01 |