| Parameter |
Value |
| Designation |
C/2024 J4 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2025-04-26T00:33:14.241600Z |
| Orbit solution date (soln_date, UTC) |
2026-03-31T09:42:18Z |
| Obs used |
677 |
| NEO |
- |
| M1 |
6.800 |
| K1 |
11.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2024-05-11T09:58:56.611200Z |
| Discovery magnitude (MPC) |
20.17 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-03-17.0000000 |
| e |
0.99911624 |
| q (au) |
5.695140 |
| a (au) |
6444.192370 |
| i (deg) |
117.532023 |
| Ω (om, deg) |
19.302979 |
| ω (w, deg) |
127.858935 |
| M (ma, deg) |
359.999924 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.107 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.107 |
| n |
6.000 |
| gf |
0.974 |
| gb |
-0.998 |
| k |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
14:31:45.06 |
+06:30:45.5 |
HIP 71052 |
10.90 |
| 2026-03-26 12:00 |
14:31:18.23 |
+06:31:18.2 |
HIP 71052 |
12.93 |
| 2026-03-27 00:00 |
14:30:51.26 |
+06:31:50.4 |
HIP 70909 |
13.84 |
| 2026-03-27 12:00 |
14:30:24.15 |
+06:32:22.2 |
HIP 70909 |
8.24 |
| 2026-03-28 00:00 |
14:29:56.92 |
+06:32:53.5 |
HIP 70909 |
5.95 |
| 2026-03-28 12:00 |
14:29:29.57 |
+06:33:24.3 |
HIP 70909 |
9.78 |
| 2026-03-29 00:00 |
14:29:02.09 |
+06:33:54.7 |
HIP 70751 |
13.03 |
| 2026-03-29 12:00 |
14:28:34.49 |
+06:34:24.5 |
HIP 70751 |
6.34 |
| 2026-03-30 00:00 |
14:28:06.76 |
+06:34:53.8 |
HIP 70751 |
2.30 |
| 2026-03-30 12:00 |
14:27:38.92 |
+06:35:22.5 |
HIP 70751 |
8.12 |
| 2026-03-31 00:00 |
14:27:10.97 |
+06:35:50.7 |
HIP 70751 |
14.95 |
| 2026-03-31 12:00 |
14:26:42.90 |
+06:36:18.4 |
HIP 70751 |
21.89 |
| 2026-04-01 00:00 |
14:26:14.73 |
+06:36:45.4 |
HIP 70751 |
28.87 |
| 2026-04-01 12:00 |
14:25:46.45 |
+06:37:11.9 |
HIP 70348 |
35.14 |
| 2026-04-02 00:00 |
14:25:18.06 |
+06:37:37.8 |
HIP 70348 |
28.86 |
| 2026-04-02 12:00 |
14:24:49.57 |
+06:38:03.0 |
HIP 70348 |
23.01 |
| 2026-04-03 00:00 |
14:24:20.98 |
+06:38:27.7 |
HIP 70348 |
18.05 |
| 2026-04-03 12:00 |
14:23:52.29 |
+06:38:51.7 |
HIP 70342 |
14.73 |
| 2026-04-04 00:00 |
14:23:23.51 |
+06:39:15.0 |
HIP 70342 |
14.23 |
| 2026-04-04 12:00 |
14:22:54.64 |
+06:39:37.7 |
HIP 70342 |
17.05 |
| 2026-04-05 00:00 |
14:22:25.68 |
+06:39:59.7 |
HIP 70246 |
20.35 |
| 2026-04-05 12:00 |
14:21:56.63 |
+06:40:21.1 |
HIP 70246 |
20.98 |
| 2026-04-06 00:00 |
14:21:27.49 |
+06:40:41.7 |
HIP 70246 |
23.91 |
| 2026-04-06 12:00 |
14:20:58.28 |
+06:41:01.6 |
HIP 70246 |
28.45 |
| 2026-04-07 00:00 |
14:20:28.98 |
+06:41:20.8 |
HIP 70008 |
23.78 |
| 2026-04-07 12:00 |
14:19:59.62 |
+06:41:39.3 |
HIP 70008 |
20.36 |
| 2026-04-08 00:00 |
14:19:30.17 |
+06:41:57.0 |
HIP 70008 |
19.22 |
| 2026-04-08 12:00 |
14:19:00.66 |
+06:42:13.9 |
HIP 70008 |
20.77 |
| 2026-04-09 00:00 |
14:18:31.08 |
+06:42:30.1 |
HIP 69804 |
20.31 |
| 2026-04-09 12:00 |
14:18:01.43 |
+06:42:45.5 |
HIP 69804 |
13.00 |
| 2026-04-10 00:00 |
14:17:31.73 |
+06:43:00.1 |
HIP 69804 |
5.82 |
| 2026-04-10 12:00 |
14:17:01.96 |
+06:43:13.9 |
HIP 69804 |
2.77 |
| 2026-04-11 00:00 |
14:16:32.14 |
+06:43:26.9 |
HIP 69804 |
9.55 |
| 2026-04-11 12:00 |
14:16:02.27 |
+06:43:39.0 |
HIP 69804 |
16.88 |
| 2026-04-12 00:00 |
14:15:32.34 |
+06:43:50.3 |
HIP 69571 |
20.01 |
| 2026-04-12 12:00 |
14:15:02.37 |
+06:44:00.8 |
HIP 69571 |
14.58 |
| 2026-04-13 00:00 |
14:14:32.35 |
+06:44:10.4 |
HIP 69571 |
11.63 |
| 2026-04-13 12:00 |
14:14:02.30 |
+06:44:19.1 |
HIP 69571 |
12.99 |
| 2026-04-14 00:00 |
14:13:32.20 |
+06:44:26.9 |
HIP 69571 |
17.71 |
| 2026-04-14 12:00 |
14:13:02.07 |
+06:44:33.9 |
HIP 69571 |
23.89 |
| 2026-04-15 00:00 |
14:12:31.91 |
+06:44:39.9 |
HIP 69522 |
30.48 |
| 2026-04-15 12:00 |
14:12:01.72 |
+06:44:45.0 |
HIP 69522 |
35.88 |
| 2026-04-16 00:00 |
14:11:31.50 |
+06:44:49.2 |
HIP 69205 |
31.32 |