| Parameter |
Value |
| Designation |
423P/Lemmon |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-09-24T00:20:08.096640Z |
| Orbit solution date (soln_date, UTC) |
2023-03-28T19:43:45Z |
| Obs used |
96 |
| NEO |
- |
| M1 |
13.800 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-02-19.0000000 |
| e |
0.12005480 |
| q (au) |
5.418519 |
| a (au) |
6.157791 |
| i (deg) |
8.348898 |
| Ω (om, deg) |
33.347491 |
| ω (w, deg) |
80.712810 |
| M (ma, deg) |
322.394999 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.108 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.108 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.778 |
| k |
0.800 |
| δ90 |
10.000 |
| 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 |
15:29:31.66 |
-22:43:31.7 |
HIP 75816 |
3.88 |
| 2026-05-12 12:00 |
15:29:17.53 |
-22:43:01.3 |
HIP 75816 |
1.07 |
| 2026-05-13 00:00 |
15:29:03.38 |
-22:42:30.6 |
HIP 75816 |
3.00 |
| 2026-05-13 12:00 |
15:28:49.23 |
-22:41:59.7 |
HIP 75816 |
6.22 |
| 2026-05-14 00:00 |
15:28:35.06 |
-22:41:28.5 |
HIP 75816 |
9.50 |
| 2026-05-14 12:00 |
15:28:20.90 |
-22:40:56.9 |
HIP 75816 |
12.79 |
| 2026-05-15 00:00 |
15:28:06.73 |
-22:40:25.1 |
HIP 75816 |
16.10 |
| 2026-05-15 12:00 |
15:27:52.56 |
-22:39:53.1 |
HIP 75598 |
18.37 |
| 2026-05-16 00:00 |
15:27:38.39 |
-22:39:20.8 |
HIP 75598 |
15.35 |
| 2026-05-16 12:00 |
15:27:24.22 |
-22:38:48.2 |
HIP 75598 |
12.47 |
| 2026-05-17 00:00 |
15:27:10.07 |
-22:38:15.4 |
HIP 75598 |
9.87 |
| 2026-05-17 12:00 |
15:26:55.92 |
-22:37:42.4 |
HIP 75598 |
7.83 |
| 2026-05-18 00:00 |
15:26:41.78 |
-22:37:09.1 |
HIP 75598 |
6.86 |
| 2026-05-18 12:00 |
15:26:27.66 |
-22:36:35.6 |
HIP 75598 |
7.39 |
| 2026-05-19 00:00 |
15:26:13.55 |
-22:36:01.9 |
HIP 75598 |
9.16 |
| 2026-05-19 12:00 |
15:25:59.47 |
-22:35:28.0 |
HIP 75598 |
11.62 |
| 2026-05-20 00:00 |
15:25:45.40 |
-22:34:53.9 |
HIP 75598 |
14.42 |
| 2026-05-20 12:00 |
15:25:31.35 |
-22:34:19.6 |
HIP 75598 |
17.38 |
| 2026-05-21 00:00 |
15:25:17.33 |
-22:33:45.1 |
HIP 75378 |
18.05 |
| 2026-05-21 12:00 |
15:25:03.34 |
-22:33:10.5 |
HIP 75378 |
15.79 |
| 2026-05-22 00:00 |
15:24:49.38 |
-22:32:35.7 |
HIP 75378 |
13.95 |
| 2026-05-22 12:00 |
15:24:35.45 |
-22:32:00.7 |
HIP 75378 |
12.71 |
| 2026-05-23 00:00 |
15:24:21.55 |
-22:31:25.6 |
HIP 75378 |
12.24 |
| 2026-05-23 12:00 |
15:24:07.69 |
-22:30:50.4 |
HIP 75378 |
12.63 |
| 2026-05-24 00:00 |
15:23:53.86 |
-22:30:15.0 |
HIP 75378 |
13.79 |
| 2026-05-24 12:00 |
15:23:40.08 |
-22:29:39.5 |
HIP 75378 |
15.55 |
| 2026-05-25 00:00 |
15:23:26.34 |
-22:29:03.9 |
HIP 75378 |
17.73 |
| 2026-05-25 12:00 |
15:23:12.64 |
-22:28:28.2 |
HIP 75378 |
20.19 |
| 2026-05-26 00:00 |
15:22:58.99 |
-22:27:52.3 |
HIP 75159 |
20.95 |
| 2026-05-26 12:00 |
15:22:45.39 |
-22:27:16.4 |
HIP 75159 |
17.80 |
| 2026-05-27 00:00 |
15:22:31.83 |
-22:26:40.4 |
HIP 75159 |
14.69 |
| 2026-05-27 12:00 |
15:22:18.33 |
-22:26:04.3 |
HIP 75159 |
11.62 |
| 2026-05-28 00:00 |
15:22:04.88 |
-22:25:28.1 |
HIP 75159 |
8.64 |
| 2026-05-28 12:00 |
15:21:51.49 |
-22:24:51.9 |
HIP 75159 |
5.88 |
| 2026-05-29 00:00 |
15:21:38.15 |
-22:24:15.6 |
HIP 75159 |
3.78 |
| 2026-05-29 12:00 |
15:21:24.87 |
-22:23:39.3 |
HIP 75159 |
3.71 |
| 2026-05-30 00:00 |
15:21:11.66 |
-22:23:02.9 |
HIP 75159 |
5.71 |
| 2026-05-30 12:00 |
15:20:58.51 |
-22:22:26.5 |
HIP 75159 |
8.41 |
| 2026-05-31 00:00 |
15:20:45.42 |
-22:21:50.1 |
HIP 75159 |
11.30 |
| 2026-05-31 12:00 |
15:20:32.40 |
-22:21:13.6 |
HIP 75159 |
14.25 |
| 2026-06-01 00:00 |
15:20:19.44 |
-22:20:37.2 |
HIP 75159 |
17.23 |
| 2026-06-01 12:00 |
15:20:06.56 |
-22:20:00.7 |
HIP 75159 |
20.22 |
| 2026-06-02 00:00 |
15:19:53.75 |
-22:19:24.3 |
HIP 75159 |
23.21 |