| Parameter |
Value |
| Designation |
264P/Larsen |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2004-03-13T06:19:55.698240Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:10Z |
| Obs used |
112 |
| NEO |
- |
| M1 |
16.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2005-11-25.0000000 |
| e |
0.37373545 |
| q (au) |
2.438280 |
| a (au) |
3.893371 |
| i (deg) |
25.148268 |
| Ω (om, deg) |
220.967548 |
| ω (w, deg) |
346.619062 |
| M (ma, deg) |
79.766687 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.735 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.735 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-25 00:00 |
10:37:45.74 |
-09:44:38.6 |
HIP 52017 |
2.41 |
| 2026-09-25 12:00 |
10:38:33.43 |
-09:48:54.6 |
HIP 52017 |
14.79 |
| 2026-09-26 00:00 |
10:39:21.11 |
-09:53:11.0 |
HIP 52121 |
17.14 |
| 2026-09-26 12:00 |
10:40:08.78 |
-09:57:28.0 |
HIP 52288 |
15.43 |
| 2026-09-27 00:00 |
10:40:56.46 |
-10:01:45.6 |
HIP 52288 |
3.89 |
| 2026-09-27 12:00 |
10:41:44.12 |
-10:06:03.6 |
HIP 52288 |
10.22 |
| 2026-09-28 00:00 |
10:42:31.78 |
-10:10:22.1 |
HIP 52288 |
22.50 |
| 2026-09-28 12:00 |
10:43:19.44 |
-10:14:41.1 |
HIP 52561 |
28.31 |
| 2026-09-29 00:00 |
10:44:07.09 |
-10:19:00.6 |
HIP 52561 |
24.77 |
| 2026-09-29 12:00 |
10:44:54.73 |
-10:23:20.6 |
HIP 52634 |
23.49 |
| 2026-09-30 00:00 |
10:45:42.36 |
-10:27:41.1 |
HIP 52634 |
15.20 |
| 2026-09-30 12:00 |
10:46:30.00 |
-10:32:02.0 |
HIP 52634 |
14.88 |
| 2026-10-01 00:00 |
10:47:17.62 |
-10:36:23.4 |
HIP 52634 |
22.88 |
| 2026-10-01 12:00 |
10:48:05.24 |
-10:40:45.3 |
HIP 52634 |
33.72 |
| 2026-10-02 00:00 |
10:48:52.85 |
-10:45:07.6 |
HIP 52955 |
33.10 |
| 2026-10-02 12:00 |
10:49:40.45 |
-10:49:30.4 |
HIP 52955 |
34.47 |
| 2026-10-03 00:00 |
10:50:28.04 |
-10:53:53.6 |
HIP 53145 |
29.70 |
| 2026-10-03 12:00 |
10:51:15.63 |
-10:58:17.2 |
HIP 53145 |
17.30 |
| 2026-10-04 00:00 |
10:52:03.21 |
-11:02:41.2 |
HIP 53145 |
5.24 |
| 2026-10-04 12:00 |
10:52:50.78 |
-11:07:05.7 |
HIP 53145 |
8.19 |
| 2026-10-05 00:00 |
10:53:38.34 |
-11:11:30.6 |
HIP 53186 |
19.14 |
| 2026-10-05 12:00 |
10:54:25.89 |
-11:15:55.8 |
HIP 53186 |
26.57 |
| 2026-10-06 00:00 |
10:55:13.43 |
-11:20:21.5 |
HIP 53398 |
29.28 |
| 2026-10-06 12:00 |
10:56:00.97 |
-11:24:47.5 |
HIP 53568 |
29.34 |
| 2026-10-07 00:00 |
10:56:48.49 |
-11:29:13.9 |
HIP 53568 |
26.02 |
| 2026-10-07 12:00 |
10:57:36.00 |
-11:33:40.7 |
HIP 53568 |
28.36 |
| 2026-10-08 00:00 |
10:58:23.49 |
-11:38:07.9 |
HIP 53786 |
29.35 |
| 2026-10-08 12:00 |
10:59:10.98 |
-11:42:35.4 |
HIP 53786 |
16.93 |
| 2026-10-09 00:00 |
10:59:58.45 |
-11:47:03.2 |
HIP 53786 |
4.70 |
| 2026-10-09 12:00 |
11:00:45.91 |
-11:51:31.4 |
HIP 53786 |
8.21 |
| 2026-10-10 00:00 |
11:01:33.36 |
-11:55:59.8 |
HIP 53879 |
7.96 |
| 2026-10-10 12:00 |
11:02:20.79 |
-12:00:28.6 |
HIP 53879 |
14.39 |
| 2026-10-11 00:00 |
11:03:08.21 |
-12:04:57.7 |
HIP 53879 |
25.69 |
| 2026-10-11 12:00 |
11:03:55.61 |
-12:09:27.1 |
HIP 54172 |
27.80 |
| 2026-10-12 00:00 |
11:04:43.00 |
-12:13:56.8 |
HIP 54258 |
18.98 |
| 2026-10-12 12:00 |
11:05:30.37 |
-12:18:26.8 |
HIP 54258 |
11.02 |
| 2026-10-13 00:00 |
11:06:17.72 |
-12:22:57.0 |
HIP 54258 |
13.84 |
| 2026-10-13 12:00 |
11:07:05.06 |
-12:27:27.5 |
HIP 54258 |
23.87 |
| 2026-10-14 00:00 |
11:07:52.38 |
-12:31:58.2 |
HIP 54315 |
33.06 |
| 2026-10-14 12:00 |
11:08:39.69 |
-12:36:29.1 |
HIP 54315 |
37.29 |
| 2026-10-15 00:00 |
11:09:26.98 |
-12:41:00.3 |
HIP 54623 |
32.77 |
| 2026-10-15 12:00 |
11:10:14.25 |
-12:45:31.7 |
HIP 54623 |
23.01 |
| 2026-10-16 00:00 |
11:11:01.50 |
-12:50:03.4 |
HIP 54623 |
17.05 |