| Parameter |
Value |
| Designation |
280P/Larsen |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-12-11T05:00:01.716480Z |
| Orbit solution date (soln_date, UTC) |
2024-09-11T13:42:29Z |
| Obs used |
166 |
| NEO |
- |
| M1 |
15.200 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-07-09.0000000 |
| e |
0.41769582 |
| q (au) |
2.627996 |
| a (au) |
4.513099 |
| i (deg) |
11.779921 |
| Ω (om, deg) |
131.491111 |
| ω (w, deg) |
104.855623 |
| M (ma, deg) |
193.854280 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.700 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.700 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.998 |
| δ90 |
9.629 |
| 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 |
02:11:58.25 |
-00:55:45.1 |
HIP 10142 |
28.07 |
| 2026-09-25 12:00 |
02:11:46.61 |
-00:57:32.6 |
HIP 10142 |
26.98 |
| 2026-09-26 00:00 |
02:11:34.85 |
-00:59:20.2 |
HIP 10142 |
26.29 |
| 2026-09-26 12:00 |
02:11:22.98 |
-01:01:07.7 |
HIP 10142 |
26.01 |
| 2026-09-27 00:00 |
02:11:10.99 |
-01:02:55.3 |
HIP 10142 |
26.19 |
| 2026-09-27 12:00 |
02:10:58.89 |
-01:04:42.9 |
HIP 10142 |
26.81 |
| 2026-09-28 00:00 |
02:10:46.68 |
-01:06:30.4 |
HIP 10142 |
27.87 |
| 2026-09-28 12:00 |
02:10:34.36 |
-01:08:17.9 |
HIP 10213 |
28.59 |
| 2026-09-29 00:00 |
02:10:21.94 |
-01:10:05.3 |
HIP 10213 |
28.46 |
| 2026-09-29 12:00 |
02:10:09.41 |
-01:11:52.7 |
HIP 10213 |
28.80 |
| 2026-09-30 00:00 |
02:09:56.77 |
-01:13:39.9 |
HIP 10213 |
29.60 |
| 2026-09-30 12:00 |
02:09:44.03 |
-01:15:27.1 |
HIP 10213 |
30.83 |
| 2026-10-01 00:00 |
02:09:31.20 |
-01:17:14.2 |
HIP 10213 |
32.44 |
| 2026-10-01 12:00 |
02:09:18.26 |
-01:19:01.1 |
HIP 10213 |
34.40 |
| 2026-10-02 00:00 |
02:09:05.23 |
-01:20:47.8 |
HIP 10213 |
36.65 |
| 2026-10-02 12:00 |
02:08:52.10 |
-01:22:34.4 |
HIP 10213 |
39.15 |
| 2026-10-03 00:00 |
02:08:38.87 |
-01:24:20.9 |
HIP 9865 |
35.90 |
| 2026-10-03 12:00 |
02:08:25.56 |
-01:26:07.1 |
HIP 9865 |
32.30 |
| 2026-10-04 00:00 |
02:08:12.16 |
-01:27:53.1 |
HIP 9865 |
28.73 |
| 2026-10-04 12:00 |
02:07:58.66 |
-01:29:38.9 |
HIP 9865 |
25.21 |
| 2026-10-05 00:00 |
02:07:45.09 |
-01:31:24.5 |
HIP 9865 |
21.78 |
| 2026-10-05 12:00 |
02:07:31.42 |
-01:33:09.8 |
HIP 9865 |
18.50 |
| 2026-10-06 00:00 |
02:07:17.68 |
-01:34:54.8 |
HIP 9865 |
15.48 |
| 2026-10-06 12:00 |
02:07:03.86 |
-01:36:39.5 |
HIP 9865 |
12.91 |
| 2026-10-07 00:00 |
02:06:49.95 |
-01:38:23.9 |
HIP 9865 |
11.13 |
| 2026-10-07 12:00 |
02:06:35.98 |
-01:40:08.0 |
HIP 9865 |
10.56 |
| 2026-10-08 00:00 |
02:06:21.93 |
-01:41:51.8 |
HIP 9865 |
11.40 |
| 2026-10-08 12:00 |
02:06:07.80 |
-01:43:35.2 |
HIP 9865 |
13.40 |
| 2026-10-09 00:00 |
02:05:53.61 |
-01:45:18.2 |
HIP 9865 |
16.14 |
| 2026-10-09 12:00 |
02:05:39.36 |
-01:47:00.9 |
HIP 9722 |
17.70 |
| 2026-10-10 00:00 |
02:05:25.03 |
-01:48:43.1 |
HIP 9722 |
14.60 |
| 2026-10-10 12:00 |
02:05:10.65 |
-01:50:24.9 |
HIP 9722 |
12.02 |
| 2026-10-11 00:00 |
02:04:56.21 |
-01:52:06.3 |
HIP 9722 |
10.36 |
| 2026-10-11 12:00 |
02:04:41.70 |
-01:53:47.2 |
HIP 9722 |
10.12 |
| 2026-10-12 00:00 |
02:04:27.15 |
-01:55:27.6 |
HIP 9645 |
10.59 |
| 2026-10-12 12:00 |
02:04:12.54 |
-01:57:07.6 |
HIP 9645 |
7.07 |
| 2026-10-13 00:00 |
02:03:57.88 |
-01:58:47.0 |
HIP 9645 |
4.49 |
| 2026-10-13 12:00 |
02:03:43.17 |
-02:00:26.0 |
HIP 9645 |
4.76 |
| 2026-10-14 00:00 |
02:03:28.42 |
-02:02:04.4 |
HIP 9645 |
7.61 |
| 2026-10-14 12:00 |
02:03:13.62 |
-02:03:42.2 |
HIP 9645 |
11.22 |
| 2026-10-15 00:00 |
02:02:58.78 |
-02:05:19.5 |
HIP 9566 |
12.94 |
| 2026-10-15 12:00 |
02:02:43.90 |
-02:06:56.2 |
HIP 9566 |
14.73 |
| 2026-10-16 00:00 |
02:02:28.99 |
-02:08:32.3 |
HIP 9563 |
15.27 |