| Parameter |
Value |
| Designation |
C/2024 J4 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2025-04-26T00:16:13.909440Z |
| Orbit solution date (soln_date, UTC) |
2026-05-28T12:12:15Z |
| Obs used |
817 |
| NEO |
- |
| M1 |
11.800 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2024-05-11T09:58:56.611200Z |
| Discovery magnitude (MPC) |
20.17 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-05-26.0000000 |
| e |
0.99909782 |
| q (au) |
5.695134 |
| a (au) |
6312.667123 |
| i (deg) |
117.530487 |
| Ω (om, deg) |
19.305266 |
| ω (w, deg) |
127.858772 |
| M (ma, deg) |
0.000059 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.371 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.371 |
| n |
6.000 |
| gf |
0.998 |
| gb |
-0.979 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
13:29:38.54 |
+05:36:06.2 |
HIP 65855 |
25.15 |
| 2026-06-01 12:00 |
13:29:17.37 |
+05:34:33.2 |
HIP 65855 |
28.10 |
| 2026-06-02 00:00 |
13:28:56.39 |
+05:32:59.4 |
HIP 65717 |
27.85 |
| 2026-06-02 12:00 |
13:28:35.58 |
+05:31:24.6 |
HIP 65717 |
25.19 |
| 2026-06-03 00:00 |
13:28:14.95 |
+05:29:49.0 |
HIP 65717 |
23.49 |
| 2026-06-03 12:00 |
13:27:54.50 |
+05:28:12.5 |
HIP 65717 |
22.92 |
| 2026-06-04 00:00 |
13:27:34.24 |
+05:26:35.1 |
HIP 65555 |
23.36 |
| 2026-06-04 12:00 |
13:27:14.15 |
+05:24:56.8 |
HIP 65555 |
21.32 |
| 2026-06-05 00:00 |
13:26:54.25 |
+05:23:17.7 |
HIP 65555 |
20.50 |
| 2026-06-05 12:00 |
13:26:34.52 |
+05:21:37.8 |
HIP 65555 |
21.01 |
| 2026-06-06 00:00 |
13:26:14.98 |
+05:19:56.9 |
HIP 65555 |
22.73 |
| 2026-06-06 12:00 |
13:25:55.63 |
+05:18:15.3 |
HIP 65555 |
25.39 |
| 2026-06-07 00:00 |
13:25:36.46 |
+05:16:32.8 |
HIP 65428 |
27.52 |
| 2026-06-07 12:00 |
13:25:17.47 |
+05:14:49.5 |
HIP 65428 |
26.94 |
| 2026-06-08 00:00 |
13:24:58.67 |
+05:13:05.4 |
HIP 65428 |
27.32 |
| 2026-06-08 12:00 |
13:24:40.05 |
+05:11:20.4 |
HIP 65428 |
28.60 |
| 2026-06-09 00:00 |
13:24:21.62 |
+05:09:34.6 |
HIP 65428 |
30.64 |
| 2026-06-09 12:00 |
13:24:03.37 |
+05:07:48.1 |
HIP 65241 |
28.33 |
| 2026-06-10 00:00 |
13:23:45.31 |
+05:06:00.7 |
HIP 65241 |
24.02 |
| 2026-06-10 12:00 |
13:23:27.44 |
+05:04:12.5 |
HIP 65241 |
20.01 |
| 2026-06-11 00:00 |
13:23:09.75 |
+05:02:23.6 |
HIP 65241 |
16.46 |
| 2026-06-11 12:00 |
13:22:52.25 |
+05:00:33.9 |
HIP 65241 |
13.72 |
| 2026-06-12 00:00 |
13:22:34.94 |
+04:58:43.4 |
HIP 65241 |
12.29 |
| 2026-06-12 12:00 |
13:22:17.81 |
+04:56:52.1 |
HIP 65241 |
12.58 |
| 2026-06-13 00:00 |
13:22:00.87 |
+04:55:00.1 |
HIP 65241 |
14.46 |
| 2026-06-13 12:00 |
13:21:44.12 |
+04:53:07.3 |
HIP 65241 |
17.38 |
| 2026-06-14 00:00 |
13:21:27.56 |
+04:51:13.7 |
HIP 65106 |
13.47 |
| 2026-06-14 12:00 |
13:21:11.19 |
+04:49:19.5 |
HIP 65106 |
9.30 |
| 2026-06-15 00:00 |
13:20:55.00 |
+04:47:24.4 |
HIP 65106 |
5.71 |
| 2026-06-15 12:00 |
13:20:39.01 |
+04:45:28.7 |
HIP 65106 |
4.34 |
| 2026-06-16 00:00 |
13:20:23.20 |
+04:43:32.2 |
HIP 65106 |
6.65 |
| 2026-06-16 12:00 |
13:20:07.58 |
+04:41:35.1 |
HIP 65106 |
10.37 |
| 2026-06-17 00:00 |
13:19:52.15 |
+04:39:37.2 |
HIP 65106 |
14.43 |
| 2026-06-17 12:00 |
13:19:36.90 |
+04:37:38.6 |
HIP 64958 |
10.98 |
| 2026-06-18 00:00 |
13:19:21.85 |
+04:35:39.3 |
HIP 64958 |
6.95 |
| 2026-06-18 12:00 |
13:19:06.98 |
+04:33:39.4 |
HIP 64958 |
3.51 |
| 2026-06-19 00:00 |
13:18:52.30 |
+04:31:38.8 |
HIP 64958 |
3.44 |
| 2026-06-19 12:00 |
13:18:37.81 |
+04:29:37.5 |
HIP 64958 |
6.78 |
| 2026-06-20 00:00 |
13:18:23.50 |
+04:27:35.5 |
HIP 64958 |
10.67 |
| 2026-06-20 12:00 |
13:18:09.38 |
+04:25:32.9 |
HIP 64958 |
14.65 |
| 2026-06-21 00:00 |
13:17:55.45 |
+04:23:29.6 |
HIP 64958 |
18.64 |
| 2026-06-21 12:00 |
13:17:41.70 |
+04:21:25.8 |
HIP 64958 |
22.61 |
| 2026-06-22 00:00 |
13:17:28.14 |
+04:19:21.2 |
HIP 64958 |
26.56 |