| Parameter |
Value |
| Designation |
C/2004 C1 (Larsen) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2003-03-19T15:25:34.576320Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:36Z |
| Obs used |
94 |
| NEO |
- |
| M1 |
10.000 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2004-02-26.0000000 |
| e |
0.62315774 |
| q (au) |
4.359408 |
| a (au) |
11.568256 |
| i (deg) |
28.916543 |
| Ω (om, deg) |
151.954024 |
| ω (w, deg) |
316.149884 |
| M (ma, deg) |
8.600990 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.476 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.476 |
| n |
6.000 |
| gf |
0.946 |
| gb |
-0.947 |
| k |
1.000 |
| δ90 |
8.820 |
| 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 |
19:48:36.31 |
-04:53:54.7 |
HIP 97400 |
23.56 |
| 2026-09-20 12:00 |
19:48:34.27 |
-04:54:29.6 |
HIP 97400 |
22.80 |
| 2026-09-21 00:00 |
19:48:32.29 |
-04:55:04.4 |
HIP 97400 |
22.05 |
| 2026-09-21 12:00 |
19:48:30.35 |
-04:55:39.1 |
HIP 97400 |
21.31 |
| 2026-09-22 00:00 |
19:48:28.46 |
-04:56:13.8 |
HIP 97400 |
20.57 |
| 2026-09-22 12:00 |
19:48:26.62 |
-04:56:48.5 |
HIP 97400 |
19.84 |
| 2026-09-23 00:00 |
19:48:24.83 |
-04:57:23.1 |
HIP 97400 |
19.12 |
| 2026-09-23 12:00 |
19:48:23.10 |
-04:57:57.6 |
HIP 97400 |
18.41 |
| 2026-09-24 00:00 |
19:48:21.41 |
-04:58:32.1 |
HIP 97400 |
17.70 |
| 2026-09-24 12:00 |
19:48:19.77 |
-04:59:06.5 |
HIP 97400 |
17.00 |
| 2026-09-25 00:00 |
19:48:18.19 |
-04:59:40.8 |
HIP 97400 |
16.31 |
| 2026-09-25 12:00 |
19:48:16.65 |
-05:00:15.1 |
HIP 97400 |
15.62 |
| 2026-09-26 00:00 |
19:48:15.17 |
-05:00:49.3 |
HIP 97400 |
14.95 |
| 2026-09-26 12:00 |
19:48:13.74 |
-05:01:23.5 |
HIP 97400 |
14.28 |
| 2026-09-27 00:00 |
19:48:12.36 |
-05:01:57.5 |
HIP 97400 |
13.62 |
| 2026-09-27 12:00 |
19:48:11.03 |
-05:02:31.5 |
HIP 97400 |
12.96 |
| 2026-09-28 00:00 |
19:48:09.75 |
-05:03:05.4 |
HIP 97400 |
12.31 |
| 2026-09-28 12:00 |
19:48:08.53 |
-05:03:39.2 |
HIP 97400 |
11.67 |
| 2026-09-29 00:00 |
19:48:07.36 |
-05:04:13.0 |
HIP 97400 |
11.04 |
| 2026-09-29 12:00 |
19:48:06.23 |
-05:04:46.6 |
HIP 97400 |
10.41 |
| 2026-09-30 00:00 |
19:48:05.17 |
-05:05:20.2 |
HIP 97400 |
9.79 |
| 2026-09-30 12:00 |
19:48:04.15 |
-05:05:53.7 |
HIP 97400 |
9.18 |
| 2026-10-01 00:00 |
19:48:03.18 |
-05:06:27.1 |
HIP 97400 |
8.58 |
| 2026-10-01 12:00 |
19:48:02.27 |
-05:07:00.4 |
HIP 97400 |
7.98 |
| 2026-10-02 00:00 |
19:48:01.41 |
-05:07:33.6 |
HIP 97400 |
7.39 |
| 2026-10-02 12:00 |
19:48:00.61 |
-05:08:06.7 |
HIP 97400 |
6.81 |
| 2026-10-03 00:00 |
19:47:59.85 |
-05:08:39.7 |
HIP 97400 |
6.24 |
| 2026-10-03 12:00 |
19:47:59.15 |
-05:09:12.6 |
HIP 97400 |
5.68 |
| 2026-10-04 00:00 |
19:47:58.51 |
-05:09:45.4 |
HIP 97400 |
5.14 |
| 2026-10-04 12:00 |
19:47:57.91 |
-05:10:18.1 |
HIP 97400 |
4.61 |
| 2026-10-05 00:00 |
19:47:57.37 |
-05:10:50.7 |
HIP 97400 |
4.10 |
| 2026-10-05 12:00 |
19:47:56.88 |
-05:11:23.2 |
HIP 97400 |
3.61 |
| 2026-10-06 00:00 |
19:47:56.45 |
-05:11:55.6 |
HIP 97400 |
3.16 |
| 2026-10-06 12:00 |
19:47:56.07 |
-05:12:27.8 |
HIP 97400 |
2.75 |
| 2026-10-07 00:00 |
19:47:55.74 |
-05:13:00.0 |
HIP 97400 |
2.41 |
| 2026-10-07 12:00 |
19:47:55.47 |
-05:13:31.9 |
HIP 97400 |
2.17 |
| 2026-10-08 00:00 |
19:47:55.25 |
-05:14:03.8 |
HIP 97400 |
2.07 |
| 2026-10-08 12:00 |
19:47:55.08 |
-05:14:35.6 |
HIP 97400 |
2.11 |
| 2026-10-09 00:00 |
19:47:54.97 |
-05:15:07.2 |
HIP 97400 |
2.28 |
| 2026-10-09 12:00 |
19:47:54.92 |
-05:15:38.7 |
HIP 97400 |
2.57 |
| 2026-10-10 00:00 |
19:47:54.91 |
-05:16:10.1 |
HIP 97400 |
2.93 |
| 2026-10-10 12:00 |
19:47:54.96 |
-05:16:41.3 |
HIP 97400 |
3.34 |
| 2026-10-11 00:00 |
19:47:55.07 |
-05:17:12.4 |
HIP 97400 |
3.78 |