| Parameter |
Value |
| Designation |
250P/Larson |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2018-02-01T20:31:02.945280Z |
| Orbit solution date (soln_date, UTC) |
2026-05-28T12:12:25Z |
| Obs used |
571 |
| NEO |
- |
| M1 |
14.600 |
| K1 |
10.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-08-24.0000000 |
| e |
0.40736973 |
| q (au) |
2.212476 |
| a (au) |
3.733316 |
| i (deg) |
13.289115 |
| Ω (om, deg) |
73.709887 |
| ω (w, deg) |
45.028545 |
| M (ma, deg) |
238.004787 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.845 + 3.530\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.845 |
| n |
3.530 |
| gf |
0.982 |
| gb |
-0.684 |
| k |
0.800 |
| δ90 |
4.965 |
| 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 |
13:54:43.54 |
-04:58:13.3 |
HIP 67931 |
30.75 |
| 2026-07-29 12:00 |
13:55:02.26 |
-05:01:41.0 |
HIP 67931 |
34.56 |
| 2026-07-30 00:00 |
13:55:21.14 |
-05:05:08.9 |
HIP 67931 |
38.89 |
| 2026-07-30 12:00 |
13:55:40.18 |
-05:08:37.0 |
HIP 68192 |
35.97 |
| 2026-07-31 00:00 |
13:55:59.37 |
-05:12:05.5 |
HIP 68192 |
30.06 |
| 2026-07-31 12:00 |
13:56:18.73 |
-05:15:34.2 |
HIP 68192 |
24.12 |
| 2026-08-01 00:00 |
13:56:38.25 |
-05:19:03.1 |
HIP 68192 |
18.15 |
| 2026-08-01 12:00 |
13:56:57.92 |
-05:22:32.3 |
HIP 68192 |
12.15 |
| 2026-08-02 00:00 |
13:57:17.75 |
-05:26:01.8 |
HIP 68192 |
6.13 |
| 2026-08-02 12:00 |
13:57:37.73 |
-05:29:31.4 |
HIP 68192 |
0.79 |
| 2026-08-03 00:00 |
13:57:57.87 |
-05:33:01.3 |
HIP 68192 |
6.16 |
| 2026-08-03 12:00 |
13:58:18.16 |
-05:36:31.5 |
HIP 68192 |
12.28 |
| 2026-08-04 00:00 |
13:58:38.60 |
-05:40:01.8 |
HIP 68192 |
18.44 |
| 2026-08-04 12:00 |
13:58:59.20 |
-05:43:32.3 |
HIP 68348 |
19.47 |
| 2026-08-05 00:00 |
13:59:19.94 |
-05:47:03.1 |
HIP 68348 |
21.73 |
| 2026-08-05 12:00 |
13:59:40.83 |
-05:50:34.0 |
HIP 68348 |
25.38 |
| 2026-08-06 00:00 |
14:00:01.87 |
-05:54:05.2 |
HIP 68524 |
28.99 |
| 2026-08-06 12:00 |
14:00:23.06 |
-05:57:36.5 |
HIP 68524 |
26.70 |
| 2026-08-07 00:00 |
14:00:44.39 |
-06:01:08.0 |
HIP 68524 |
25.79 |
| 2026-08-07 12:00 |
14:01:05.87 |
-06:04:39.6 |
HIP 68524 |
26.41 |
| 2026-08-08 00:00 |
14:01:27.49 |
-06:08:11.5 |
HIP 68524 |
28.50 |
| 2026-08-08 12:00 |
14:01:49.26 |
-06:11:43.5 |
HIP 68636 |
25.59 |
| 2026-08-09 00:00 |
14:02:11.17 |
-06:15:15.7 |
HIP 68636 |
19.38 |
| 2026-08-09 12:00 |
14:02:33.22 |
-06:18:48.0 |
HIP 68636 |
13.41 |
| 2026-08-10 00:00 |
14:02:55.41 |
-06:22:20.4 |
HIP 68636 |
8.33 |
| 2026-08-10 12:00 |
14:03:17.74 |
-06:25:53.0 |
HIP 68636 |
6.70 |
| 2026-08-11 00:00 |
14:03:40.21 |
-06:29:25.8 |
HIP 68738 |
8.24 |
| 2026-08-11 12:00 |
14:04:02.82 |
-06:32:58.6 |
HIP 68738 |
5.53 |
| 2026-08-12 00:00 |
14:04:25.57 |
-06:36:31.6 |
HIP 68789 |
6.68 |
| 2026-08-12 12:00 |
14:04:48.45 |
-06:40:04.7 |
HIP 68789 |
6.93 |
| 2026-08-13 00:00 |
14:05:11.47 |
-06:43:37.9 |
HIP 68789 |
11.91 |
| 2026-08-13 12:00 |
14:05:34.62 |
-06:47:11.1 |
HIP 68789 |
18.08 |
| 2026-08-14 00:00 |
14:05:57.90 |
-06:50:44.5 |
HIP 68789 |
24.58 |
| 2026-08-14 12:00 |
14:06:21.31 |
-06:54:18.0 |
HIP 68806 |
28.07 |
| 2026-08-15 00:00 |
14:06:44.86 |
-06:57:51.5 |
HIP 68806 |
29.58 |
| 2026-08-15 12:00 |
14:07:08.53 |
-07:01:25.1 |
HIP 68806 |
32.52 |
| 2026-08-16 00:00 |
14:07:32.34 |
-07:04:58.8 |
HIP 69195 |
36.17 |
| 2026-08-16 12:00 |
14:07:56.27 |
-07:08:32.5 |
HIP 69195 |
29.96 |
| 2026-08-17 00:00 |
14:08:20.32 |
-07:12:06.3 |
HIP 69195 |
24.10 |
| 2026-08-17 12:00 |
14:08:44.50 |
-07:15:40.1 |
HIP 69195 |
18.97 |
| 2026-08-18 00:00 |
14:09:08.81 |
-07:19:13.9 |
HIP 69195 |
15.34 |
| 2026-08-18 12:00 |
14:09:33.24 |
-07:22:47.8 |
HIP 69195 |
14.45 |
| 2026-08-19 00:00 |
14:09:57.79 |
-07:26:21.7 |
HIP 69195 |
16.76 |