| 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) |
| 2026-07-29 00:00 |
02:17:21.13 |
+01:38:01.9 |
HIP 10723 |
12.45 |
| 2026-07-29 12:00 |
02:17:27.57 |
+01:37:27.2 |
HIP 10723 |
11.58 |
| 2026-07-30 00:00 |
02:17:33.87 |
+01:36:51.6 |
HIP 10723 |
10.95 |
| 2026-07-30 12:00 |
02:17:40.01 |
+01:36:15.0 |
HIP 10723 |
10.59 |
| 2026-07-31 00:00 |
02:17:46.00 |
+01:35:37.5 |
HIP 10723 |
10.50 |
| 2026-07-31 12:00 |
02:17:51.84 |
+01:34:59.1 |
HIP 10723 |
10.69 |
| 2026-08-01 00:00 |
02:17:57.53 |
+01:34:19.7 |
HIP 10723 |
11.12 |
| 2026-08-01 12:00 |
02:18:03.07 |
+01:33:39.4 |
HIP 10723 |
11.77 |
| 2026-08-02 00:00 |
02:18:08.45 |
+01:32:58.2 |
HIP 10723 |
12.57 |
| 2026-08-02 12:00 |
02:18:13.68 |
+01:32:16.1 |
HIP 10723 |
13.51 |
| 2026-08-03 00:00 |
02:18:18.75 |
+01:31:33.0 |
HIP 10723 |
14.54 |
| 2026-08-03 12:00 |
02:18:23.67 |
+01:30:49.0 |
HIP 10723 |
15.64 |
| 2026-08-04 00:00 |
02:18:28.43 |
+01:30:04.1 |
HIP 10723 |
16.78 |
| 2026-08-04 12:00 |
02:18:33.04 |
+01:29:18.3 |
HIP 10723 |
17.96 |
| 2026-08-05 00:00 |
02:18:37.49 |
+01:28:31.5 |
HIP 10697 |
18.36 |
| 2026-08-05 12:00 |
02:18:41.78 |
+01:27:43.8 |
HIP 10697 |
18.69 |
| 2026-08-06 00:00 |
02:18:45.92 |
+01:26:55.2 |
HIP 10697 |
19.06 |
| 2026-08-06 12:00 |
02:18:49.90 |
+01:26:05.7 |
HIP 10697 |
19.48 |
| 2026-08-07 00:00 |
02:18:53.71 |
+01:25:15.3 |
HIP 10697 |
19.93 |
| 2026-08-07 12:00 |
02:18:57.37 |
+01:24:24.0 |
HIP 10697 |
20.41 |
| 2026-08-08 00:00 |
02:19:00.86 |
+01:23:31.7 |
HIP 10697 |
20.90 |
| 2026-08-08 12:00 |
02:19:04.20 |
+01:22:38.5 |
HIP 10697 |
21.42 |
| 2026-08-09 00:00 |
02:19:07.37 |
+01:21:44.5 |
HIP 10697 |
21.94 |
| 2026-08-09 12:00 |
02:19:10.38 |
+01:20:49.5 |
HIP 10697 |
22.48 |
| 2026-08-10 00:00 |
02:19:13.23 |
+01:19:53.6 |
HIP 10697 |
23.02 |
| 2026-08-10 12:00 |
02:19:15.92 |
+01:18:56.9 |
HIP 10697 |
23.57 |
| 2026-08-11 00:00 |
02:19:18.44 |
+01:17:59.2 |
HIP 10697 |
24.11 |
| 2026-08-11 12:00 |
02:19:20.80 |
+01:17:00.7 |
HIP 10697 |
24.66 |
| 2026-08-12 00:00 |
02:19:22.99 |
+01:16:01.2 |
HIP 10697 |
25.21 |
| 2026-08-12 12:00 |
02:19:25.02 |
+01:15:00.9 |
HIP 10697 |
25.75 |
| 2026-08-13 00:00 |
02:19:26.89 |
+01:13:59.8 |
HIP 10697 |
26.29 |
| 2026-08-13 12:00 |
02:19:28.59 |
+01:12:57.7 |
HIP 10697 |
26.83 |
| 2026-08-14 00:00 |
02:19:30.12 |
+01:11:54.8 |
HIP 10697 |
27.37 |
| 2026-08-14 12:00 |
02:19:31.49 |
+01:10:51.0 |
HIP 10697 |
27.90 |
| 2026-08-15 00:00 |
02:19:32.69 |
+01:09:46.4 |
HIP 10697 |
28.42 |
| 2026-08-15 12:00 |
02:19:33.72 |
+01:08:40.9 |
HIP 10697 |
28.95 |
| 2026-08-16 00:00 |
02:19:34.59 |
+01:07:34.5 |
HIP 10697 |
29.47 |
| 2026-08-16 12:00 |
02:19:35.29 |
+01:06:27.4 |
HIP 10697 |
30.00 |
| 2026-08-17 00:00 |
02:19:35.83 |
+01:05:19.4 |
HIP 10697 |
30.52 |
| 2026-08-17 12:00 |
02:19:36.20 |
+01:04:10.5 |
HIP 10697 |
31.04 |
| 2026-08-18 00:00 |
02:19:36.40 |
+01:03:00.9 |
HIP 10697 |
31.56 |
| 2026-08-18 12:00 |
02:19:36.44 |
+01:01:50.4 |
HIP 10697 |
32.09 |
| 2026-08-19 00:00 |
02:19:36.30 |
+01:00:39.1 |
HIP 10697 |
32.62 |