| 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) |
| 2026-05-12 00:00 |
01:37:19.23 |
+00:05:39.2 |
HIP 7549 |
26.67 |
| 2026-05-12 12:00 |
01:37:40.65 |
+00:07:15.8 |
HIP 7549 |
28.93 |
| 2026-05-13 00:00 |
01:38:02.03 |
+00:08:51.6 |
HIP 7646 |
30.99 |
| 2026-05-13 12:00 |
01:38:23.37 |
+00:10:26.9 |
HIP 7646 |
28.67 |
| 2026-05-14 00:00 |
01:38:44.66 |
+00:12:01.5 |
HIP 7724 |
26.69 |
| 2026-05-14 12:00 |
01:39:05.90 |
+00:13:35.4 |
HIP 7724 |
23.63 |
| 2026-05-15 00:00 |
01:39:27.10 |
+00:15:08.7 |
HIP 7724 |
21.59 |
| 2026-05-15 12:00 |
01:39:48.25 |
+00:16:41.4 |
HIP 7840 |
17.65 |
| 2026-05-16 00:00 |
01:40:09.36 |
+00:18:13.3 |
HIP 7840 |
12.29 |
| 2026-05-16 12:00 |
01:40:30.41 |
+00:19:44.6 |
HIP 7840 |
7.15 |
| 2026-05-17 00:00 |
01:40:51.42 |
+00:21:15.2 |
HIP 7840 |
3.37 |
| 2026-05-17 12:00 |
01:41:12.37 |
+00:22:45.2 |
HIP 7840 |
5.58 |
| 2026-05-18 00:00 |
01:41:33.28 |
+00:24:14.5 |
HIP 7840 |
10.49 |
| 2026-05-18 12:00 |
01:41:54.13 |
+00:25:43.1 |
HIP 7840 |
15.74 |
| 2026-05-19 00:00 |
01:42:14.94 |
+00:27:11.0 |
HIP 7840 |
21.05 |
| 2026-05-19 12:00 |
01:42:35.69 |
+00:28:38.2 |
HIP 7871 |
25.26 |
| 2026-05-20 00:00 |
01:42:56.38 |
+00:30:04.7 |
HIP 8080 |
27.18 |
| 2026-05-20 12:00 |
01:43:17.03 |
+00:31:30.5 |
HIP 8080 |
23.84 |
| 2026-05-21 00:00 |
01:43:37.61 |
+00:32:55.6 |
HIP 8080 |
21.35 |
| 2026-05-21 12:00 |
01:43:58.15 |
+00:34:20.0 |
HIP 8080 |
20.02 |
| 2026-05-22 00:00 |
01:44:18.62 |
+00:35:43.8 |
HIP 8080 |
20.06 |
| 2026-05-22 12:00 |
01:44:39.05 |
+00:37:06.8 |
HIP 8080 |
21.45 |
| 2026-05-23 00:00 |
01:44:59.41 |
+00:38:29.1 |
HIP 8080 |
23.96 |
| 2026-05-23 12:00 |
01:45:19.72 |
+00:39:50.7 |
HIP 8080 |
27.26 |
| 2026-05-24 00:00 |
01:45:39.96 |
+00:41:11.5 |
HIP 8328 |
26.52 |
| 2026-05-24 12:00 |
01:46:00.15 |
+00:42:31.7 |
HIP 8328 |
21.30 |
| 2026-05-25 00:00 |
01:46:20.28 |
+00:43:51.1 |
HIP 8328 |
16.10 |
| 2026-05-25 12:00 |
01:46:40.35 |
+00:45:09.9 |
HIP 8328 |
10.92 |
| 2026-05-26 00:00 |
01:47:00.36 |
+00:46:27.9 |
HIP 8328 |
5.79 |
| 2026-05-26 12:00 |
01:47:20.31 |
+00:47:45.1 |
HIP 8328 |
1.04 |
| 2026-05-27 00:00 |
01:47:40.20 |
+00:49:01.7 |
HIP 8328 |
4.64 |
| 2026-05-27 12:00 |
01:48:00.02 |
+00:50:17.5 |
HIP 8328 |
9.72 |
| 2026-05-28 00:00 |
01:48:19.78 |
+00:51:32.6 |
HIP 8328 |
14.80 |
| 2026-05-28 12:00 |
01:48:39.48 |
+00:52:46.9 |
HIP 8328 |
19.87 |
| 2026-05-29 00:00 |
01:48:59.12 |
+00:54:00.5 |
HIP 8328 |
24.93 |
| 2026-05-29 12:00 |
01:49:18.69 |
+00:55:13.4 |
HIP 8454 |
25.09 |
| 2026-05-30 00:00 |
01:49:38.19 |
+00:56:25.5 |
HIP 8454 |
25.30 |
| 2026-05-30 12:00 |
01:49:57.63 |
+00:57:36.9 |
HIP 8639 |
23.48 |
| 2026-05-31 00:00 |
01:50:17.00 |
+00:58:47.5 |
HIP 8639 |
19.58 |
| 2026-05-31 12:00 |
01:50:36.31 |
+00:59:57.4 |
HIP 8639 |
16.28 |
| 2026-06-01 00:00 |
01:50:55.55 |
+01:01:06.5 |
HIP 8639 |
14.00 |
| 2026-06-01 12:00 |
01:51:14.72 |
+01:02:14.9 |
HIP 8639 |
13.25 |
| 2026-06-02 00:00 |
01:51:33.83 |
+01:03:22.5 |
HIP 8639 |
14.26 |