280P/Larsen
| 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
$$
M_a = (14.698 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.698 |
| n |
6.000 |
| gf |
0.979 |
| gb |
-1.000 |
| k |
0.998 |
| δ90 |
9.779 |
| 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) |
| 2026-02-03 00:00 |
00:25:36.70 |
-07:15:02.5 |
HIP 2143 |
43.79 |
| 2026-02-03 12:00 |
00:25:55.25 |
-07:12:37.5 |
HIP 2143 |
43.80 |
| 2026-02-04 00:00 |
00:26:13.87 |
-07:10:12.2 |
HIP 2143 |
44.42 |
| 2026-02-04 12:00 |
00:26:32.58 |
-07:07:46.7 |
HIP 2201 |
43.23 |
| 2026-02-05 00:00 |
00:26:51.36 |
-07:05:21.0 |
HIP 2201 |
39.11 |
| 2026-02-05 12:00 |
00:27:10.21 |
-07:02:55.1 |
HIP 2201 |
35.28 |
| 2026-02-06 00:00 |
00:27:29.15 |
-07:00:29.0 |
HIP 2201 |
31.87 |
| 2026-02-06 12:00 |
00:27:48.16 |
-06:58:02.7 |
HIP 2201 |
29.02 |
| 2026-02-07 00:00 |
00:28:07.25 |
-06:55:36.2 |
HIP 2201 |
26.92 |
| 2026-02-07 12:00 |
00:28:26.41 |
-06:53:09.5 |
HIP 2201 |
25.79 |
| 2026-02-08 00:00 |
00:28:45.64 |
-06:50:42.6 |
HIP 2302 |
21.72 |
| 2026-02-08 12:00 |
00:29:04.95 |
-06:48:15.6 |
HIP 2302 |
17.85 |
| 2026-02-09 00:00 |
00:29:24.33 |
-06:45:48.3 |
HIP 2302 |
14.95 |
| 2026-02-09 12:00 |
00:29:43.78 |
-06:43:20.9 |
HIP 2302 |
13.66 |
| 2026-02-10 00:00 |
00:30:03.30 |
-06:40:53.4 |
HIP 2302 |
14.46 |
| 2026-02-10 12:00 |
00:30:22.90 |
-06:38:25.7 |
HIP 2302 |
17.06 |
| 2026-02-11 00:00 |
00:30:42.56 |
-06:35:57.8 |
HIP 2302 |
20.81 |
| 2026-02-11 12:00 |
00:31:02.29 |
-06:33:29.8 |
HIP 2302 |
25.22 |
| 2026-02-12 00:00 |
00:31:22.09 |
-06:31:01.7 |
HIP 2566 |
25.98 |
| 2026-02-12 12:00 |
00:31:41.95 |
-06:28:33.4 |
HIP 2566 |
20.85 |
| 2026-02-13 00:00 |
00:32:01.89 |
-06:26:05.1 |
HIP 2566 |
15.96 |
| 2026-02-13 12:00 |
00:32:21.88 |
-06:23:36.5 |
HIP 2566 |
11.66 |
| 2026-02-14 00:00 |
00:32:41.95 |
-06:21:07.9 |
HIP 2566 |
8.88 |
| 2026-02-14 12:00 |
00:33:02.07 |
-06:18:39.2 |
HIP 2566 |
9.15 |
| 2026-02-15 00:00 |
00:33:22.26 |
-06:16:10.3 |
HIP 2566 |
12.31 |
| 2026-02-15 12:00 |
00:33:42.52 |
-06:13:41.4 |
HIP 2566 |
16.81 |
| 2026-02-16 00:00 |
00:34:02.83 |
-06:11:12.4 |
HIP 2710 |
19.96 |
| 2026-02-16 12:00 |
00:34:23.21 |
-06:08:43.3 |
HIP 2785 |
16.96 |
| 2026-02-17 00:00 |
00:34:43.65 |
-06:06:14.1 |
HIP 2785 |
12.08 |
| 2026-02-17 12:00 |
00:35:04.14 |
-06:03:44.8 |
HIP 2785 |
8.26 |
| 2026-02-18 00:00 |
00:35:24.70 |
-06:01:15.5 |
HIP 2785 |
7.39 |
| 2026-02-18 12:00 |
00:35:45.31 |
-05:58:46.1 |
HIP 2785 |
10.28 |
| 2026-02-19 00:00 |
00:36:05.98 |
-05:56:16.6 |
HIP 2785 |
14.90 |
| 2026-02-19 12:00 |
00:36:26.71 |
-05:53:47.1 |
HIP 2919 |
14.93 |
| 2026-02-20 00:00 |
00:36:47.49 |
-05:51:17.6 |
HIP 2919 |
15.55 |
| 2026-02-20 12:00 |
00:37:08.33 |
-05:48:48.0 |
HIP 2980 |
16.38 |
| 2026-02-21 00:00 |
00:37:29.22 |
-05:46:18.4 |
HIP 2980 |
15.21 |
| 2026-02-21 12:00 |
00:37:50.17 |
-05:43:48.8 |
HIP 2980 |
16.15 |
| 2026-02-22 00:00 |
00:38:11.16 |
-05:41:19.1 |
HIP 2980 |
18.90 |
| 2026-02-22 12:00 |
00:38:32.21 |
-05:38:49.5 |
HIP 2980 |
22.81 |
| 2026-02-23 00:00 |
00:38:53.31 |
-05:36:19.8 |
HIP 2980 |
27.41 |
| 2026-02-23 12:00 |
00:39:14.46 |
-05:33:50.1 |
HIP 2980 |
32.41 |
| 2026-02-24 00:00 |
00:39:35.65 |
-05:31:20.5 |
HIP 2980 |
37.66 |