| 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) |
| 2026-07-29 00:00 |
19:55:53.36 |
-03:56:39.2 |
HIP 97901 |
34.34 |
| 2026-07-29 12:00 |
19:55:47.92 |
-03:57:04.6 |
HIP 97901 |
33.23 |
| 2026-07-30 00:00 |
19:55:42.50 |
-03:57:30.3 |
HIP 97901 |
32.14 |
| 2026-07-30 12:00 |
19:55:37.08 |
-03:57:56.2 |
HIP 97901 |
31.09 |
| 2026-07-31 00:00 |
19:55:31.67 |
-03:58:22.2 |
HIP 97901 |
30.07 |
| 2026-07-31 12:00 |
19:55:26.28 |
-03:58:48.5 |
HIP 97901 |
29.08 |
| 2026-08-01 00:00 |
19:55:20.89 |
-03:59:15.0 |
HIP 97901 |
28.14 |
| 2026-08-01 12:00 |
19:55:15.52 |
-03:59:41.7 |
HIP 97901 |
27.24 |
| 2026-08-02 00:00 |
19:55:10.16 |
-04:00:08.6 |
HIP 97901 |
26.39 |
| 2026-08-02 12:00 |
19:55:04.81 |
-04:00:35.6 |
HIP 97901 |
25.59 |
| 2026-08-03 00:00 |
19:54:59.47 |
-04:01:02.9 |
HIP 97901 |
24.86 |
| 2026-08-03 12:00 |
19:54:54.14 |
-04:01:30.4 |
HIP 97901 |
24.18 |
| 2026-08-04 00:00 |
19:54:48.83 |
-04:01:58.0 |
HIP 97901 |
23.58 |
| 2026-08-04 12:00 |
19:54:43.54 |
-04:02:25.8 |
HIP 97901 |
23.05 |
| 2026-08-05 00:00 |
19:54:38.26 |
-04:02:53.9 |
HIP 97901 |
22.60 |
| 2026-08-05 12:00 |
19:54:32.99 |
-04:03:22.1 |
HIP 97901 |
22.23 |
| 2026-08-06 00:00 |
19:54:27.74 |
-04:03:50.5 |
HIP 97901 |
21.96 |
| 2026-08-06 12:00 |
19:54:22.50 |
-04:04:19.1 |
HIP 97901 |
21.77 |
| 2026-08-07 00:00 |
19:54:17.29 |
-04:04:47.8 |
HIP 97901 |
21.67 |
| 2026-08-07 12:00 |
19:54:12.08 |
-04:05:16.7 |
HIP 97901 |
21.67 |
| 2026-08-08 00:00 |
19:54:06.90 |
-04:05:45.8 |
HIP 97901 |
21.75 |
| 2026-08-08 12:00 |
19:54:01.74 |
-04:06:15.1 |
HIP 97901 |
21.93 |
| 2026-08-09 00:00 |
19:53:56.59 |
-04:06:44.6 |
HIP 97901 |
22.20 |
| 2026-08-09 12:00 |
19:53:51.46 |
-04:07:14.2 |
HIP 97901 |
22.55 |
| 2026-08-10 00:00 |
19:53:46.35 |
-04:07:44.0 |
HIP 97901 |
22.98 |
| 2026-08-10 12:00 |
19:53:41.27 |
-04:08:13.9 |
HIP 97901 |
23.48 |
| 2026-08-11 00:00 |
19:53:36.20 |
-04:08:44.1 |
HIP 97901 |
24.06 |
| 2026-08-11 12:00 |
19:53:31.16 |
-04:09:14.3 |
HIP 97901 |
24.69 |
| 2026-08-12 00:00 |
19:53:26.13 |
-04:09:44.8 |
HIP 97872 |
24.69 |
| 2026-08-12 12:00 |
19:53:21.13 |
-04:10:15.3 |
HIP 97872 |
24.12 |
| 2026-08-13 00:00 |
19:53:16.16 |
-04:10:46.1 |
HIP 97872 |
23.62 |
| 2026-08-13 12:00 |
19:53:11.20 |
-04:11:17.0 |
HIP 97872 |
23.18 |
| 2026-08-14 00:00 |
19:53:06.27 |
-04:11:48.0 |
HIP 97872 |
22.80 |
| 2026-08-14 12:00 |
19:53:01.36 |
-04:12:19.2 |
HIP 97872 |
22.50 |
| 2026-08-15 00:00 |
19:52:56.48 |
-04:12:50.5 |
HIP 97872 |
22.27 |
| 2026-08-15 12:00 |
19:52:51.63 |
-04:13:21.9 |
HIP 97872 |
22.10 |
| 2026-08-16 00:00 |
19:52:46.80 |
-04:13:53.5 |
HIP 97872 |
22.02 |
| 2026-08-16 12:00 |
19:52:41.99 |
-04:14:25.3 |
HIP 97872 |
22.00 |
| 2026-08-17 00:00 |
19:52:37.22 |
-04:14:57.1 |
HIP 97872 |
22.06 |
| 2026-08-17 12:00 |
19:52:32.47 |
-04:15:29.1 |
HIP 97872 |
22.19 |
| 2026-08-18 00:00 |
19:52:27.74 |
-04:16:01.2 |
HIP 97872 |
22.39 |
| 2026-08-18 12:00 |
19:52:23.05 |
-04:16:33.5 |
HIP 97872 |
22.66 |
| 2026-08-19 00:00 |
19:52:18.39 |
-04:17:05.8 |
HIP 97872 |
22.99 |