| 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) |
| 2026-09-20 00:00 |
15:26:01.12 |
-22:39:32.6 |
HIP 75598 |
13.63 |
| 2026-09-20 12:00 |
15:26:17.21 |
-22:40:28.5 |
HIP 75598 |
11.96 |
| 2026-09-21 00:00 |
15:26:33.40 |
-22:41:24.7 |
HIP 75598 |
11.39 |
| 2026-09-21 12:00 |
15:26:49.69 |
-22:42:21.2 |
HIP 75598 |
12.09 |
| 2026-09-22 00:00 |
15:27:06.07 |
-22:43:17.9 |
HIP 75598 |
13.89 |
| 2026-09-22 12:00 |
15:27:22.54 |
-22:44:15.0 |
HIP 75598 |
16.45 |
| 2026-09-23 00:00 |
15:27:39.11 |
-22:45:12.3 |
HIP 75598 |
19.48 |
| 2026-09-23 12:00 |
15:27:55.77 |
-22:46:10.0 |
HIP 75816 |
19.00 |
| 2026-09-24 00:00 |
15:28:12.52 |
-22:47:07.9 |
HIP 75816 |
15.55 |
| 2026-09-24 12:00 |
15:28:29.36 |
-22:48:06.1 |
HIP 75816 |
12.40 |
| 2026-09-25 00:00 |
15:28:46.30 |
-22:49:04.6 |
HIP 75816 |
9.88 |
| 2026-09-25 12:00 |
15:29:03.32 |
-22:50:03.3 |
HIP 75816 |
8.59 |
| 2026-09-26 00:00 |
15:29:20.43 |
-22:51:02.3 |
HIP 75816 |
9.09 |
| 2026-09-26 12:00 |
15:29:37.63 |
-22:52:01.6 |
HIP 75816 |
11.18 |
| 2026-09-27 00:00 |
15:29:54.92 |
-22:53:01.2 |
HIP 75816 |
14.18 |
| 2026-09-27 12:00 |
15:30:12.29 |
-22:54:01.0 |
HIP 75816 |
17.65 |
| 2026-09-28 00:00 |
15:30:29.75 |
-22:55:01.0 |
HIP 75816 |
21.38 |
| 2026-09-28 12:00 |
15:30:47.30 |
-22:56:01.3 |
HIP 75816 |
25.25 |
| 2026-09-29 00:00 |
15:31:04.93 |
-22:57:01.9 |
HIP 75816 |
29.22 |
| 2026-09-29 12:00 |
15:31:22.65 |
-22:58:02.7 |
HIP 76101 |
32.12 |
| 2026-09-30 00:00 |
15:31:40.45 |
-22:59:03.7 |
HIP 76101 |
29.31 |
| 2026-09-30 12:00 |
15:31:58.34 |
-23:00:05.0 |
HIP 76101 |
26.86 |
| 2026-10-01 00:00 |
15:32:16.31 |
-23:01:06.6 |
HIP 76101 |
24.90 |
| 2026-10-01 12:00 |
15:32:34.36 |
-23:02:08.3 |
HIP 76101 |
23.54 |
| 2026-10-02 00:00 |
15:32:52.50 |
-23:03:10.3 |
HIP 76101 |
22.91 |
| 2026-10-02 12:00 |
15:33:10.71 |
-23:04:12.5 |
HIP 76101 |
23.07 |
| 2026-10-03 00:00 |
15:33:29.01 |
-23:05:15.0 |
HIP 76155 |
22.86 |
| 2026-10-03 12:00 |
15:33:47.39 |
-23:06:17.6 |
HIP 76155 |
22.80 |
| 2026-10-04 00:00 |
15:34:05.85 |
-23:07:20.5 |
HIP 76268 |
22.65 |
| 2026-10-04 12:00 |
15:34:24.39 |
-23:08:23.6 |
HIP 76268 |
22.49 |
| 2026-10-05 00:00 |
15:34:43.01 |
-23:09:26.9 |
HIP 76268 |
23.18 |
| 2026-10-05 12:00 |
15:35:01.70 |
-23:10:30.4 |
HIP 76268 |
24.66 |
| 2026-10-06 00:00 |
15:35:20.47 |
-23:11:34.1 |
HIP 76268 |
26.81 |
| 2026-10-06 12:00 |
15:35:39.33 |
-23:12:38.0 |
HIP 76268 |
29.49 |
| 2026-10-07 00:00 |
15:35:58.25 |
-23:13:42.1 |
HIP 76532 |
25.77 |
| 2026-10-07 12:00 |
15:36:17.26 |
-23:14:46.4 |
HIP 76532 |
21.79 |
| 2026-10-08 00:00 |
15:36:36.33 |
-23:15:50.9 |
HIP 76532 |
18.05 |
| 2026-10-08 12:00 |
15:36:55.49 |
-23:16:55.6 |
HIP 76532 |
14.73 |
| 2026-10-09 00:00 |
15:37:14.71 |
-23:18:00.5 |
HIP 76532 |
12.22 |
| 2026-10-09 12:00 |
15:37:34.01 |
-23:19:05.5 |
HIP 76532 |
11.08 |
| 2026-10-10 00:00 |
15:37:53.39 |
-23:20:10.8 |
HIP 76532 |
11.75 |
| 2026-10-10 12:00 |
15:38:12.83 |
-23:21:16.2 |
HIP 76532 |
13.99 |
| 2026-10-11 00:00 |
15:38:32.35 |
-23:22:21.7 |
HIP 76532 |
17.20 |