C/2024 J4 (Lemmon)
| Parameter |
Value |
| Designation |
C/2024 J4 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2025-04-26T01:04:33.398400Z |
| Orbit solution date (soln_date, UTC) |
2025-09-09T12:42:35Z |
| Obs used |
605 |
| NEO |
- |
| M1 |
6.700 |
| K1 |
11.500 |
| 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) |
2025-02-02.0000000 |
| e |
0.99910492 |
| q (au) |
5.695119 |
| a (au) |
6362.728333 |
| i (deg) |
117.533106 |
| Ω (om, deg) |
19.301024 |
| ω (w, deg) |
127.860254 |
| M (ma, deg) |
359.999839 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.106 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.106 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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) |
| 2026-02-03 00:00 |
15:01:33.53 |
+05:38:55.1 |
HIP 73529 |
3.07 |
| 2026-02-03 12:00 |
15:01:25.93 |
+05:39:03.0 |
HIP 73529 |
4.92 |
| 2026-02-04 00:00 |
15:01:18.14 |
+05:39:11.5 |
HIP 73529 |
6.85 |
| 2026-02-04 12:00 |
15:01:10.17 |
+05:39:20.9 |
HIP 73529 |
8.83 |
| 2026-02-05 00:00 |
15:01:02.00 |
+05:39:30.9 |
HIP 73529 |
10.86 |
| 2026-02-05 12:00 |
15:00:53.64 |
+05:39:41.7 |
HIP 73529 |
12.94 |
| 2026-02-06 00:00 |
15:00:45.09 |
+05:39:53.3 |
HIP 73529 |
15.08 |
| 2026-02-06 12:00 |
15:00:36.35 |
+05:40:05.5 |
HIP 73529 |
17.26 |
| 2026-02-07 00:00 |
15:00:27.42 |
+05:40:18.5 |
HIP 73529 |
19.49 |
| 2026-02-07 12:00 |
15:00:18.29 |
+05:40:32.2 |
HIP 73529 |
21.77 |
| 2026-02-08 00:00 |
15:00:08.97 |
+05:40:46.6 |
HIP 73456 |
22.56 |
| 2026-02-08 12:00 |
14:59:59.46 |
+05:41:01.7 |
HIP 73456 |
23.27 |
| 2026-02-09 00:00 |
14:59:49.74 |
+05:41:17.5 |
HIP 73456 |
24.21 |
| 2026-02-09 12:00 |
14:59:39.84 |
+05:41:33.9 |
HIP 73243 |
25.10 |
| 2026-02-10 00:00 |
14:59:29.73 |
+05:41:51.1 |
HIP 73243 |
22.73 |
| 2026-02-10 12:00 |
14:59:19.43 |
+05:42:08.9 |
HIP 73243 |
20.36 |
| 2026-02-11 00:00 |
14:59:08.93 |
+05:42:27.4 |
HIP 73243 |
18.00 |
| 2026-02-11 12:00 |
14:58:58.23 |
+05:42:46.6 |
HIP 73243 |
15.69 |
| 2026-02-12 00:00 |
14:58:47.33 |
+05:43:06.3 |
HIP 73243 |
13.46 |
| 2026-02-12 12:00 |
14:58:36.23 |
+05:43:26.8 |
HIP 73243 |
11.42 |
| 2026-02-13 00:00 |
14:58:24.93 |
+05:43:47.8 |
HIP 73243 |
9.72 |
| 2026-02-13 12:00 |
14:58:13.43 |
+05:44:09.5 |
HIP 73243 |
8.62 |
| 2026-02-14 00:00 |
14:58:01.73 |
+05:44:31.8 |
HIP 73243 |
8.41 |
| 2026-02-14 12:00 |
14:57:49.82 |
+05:44:54.7 |
HIP 73243 |
9.21 |
| 2026-02-15 00:00 |
14:57:37.71 |
+05:45:18.2 |
HIP 73243 |
10.83 |
| 2026-02-15 12:00 |
14:57:25.40 |
+05:45:42.3 |
HIP 73243 |
13.01 |
| 2026-02-16 00:00 |
14:57:12.89 |
+05:46:06.9 |
HIP 73243 |
15.54 |
| 2026-02-16 12:00 |
14:57:00.17 |
+05:46:32.1 |
HIP 73243 |
18.31 |
| 2026-02-17 00:00 |
14:56:47.25 |
+05:46:57.9 |
HIP 73243 |
21.24 |
| 2026-02-17 12:00 |
14:56:34.12 |
+05:47:24.2 |
HIP 73092 |
22.59 |
| 2026-02-18 00:00 |
14:56:20.79 |
+05:47:51.1 |
HIP 73004 |
21.63 |
| 2026-02-18 12:00 |
14:56:07.26 |
+05:48:18.5 |
HIP 73004 |
18.75 |
| 2026-02-19 00:00 |
14:55:53.52 |
+05:48:46.4 |
HIP 73004 |
16.02 |
| 2026-02-19 12:00 |
14:55:39.57 |
+05:49:14.8 |
HIP 73004 |
13.60 |
| 2026-02-20 00:00 |
14:55:25.42 |
+05:49:43.7 |
HIP 73004 |
11.71 |
| 2026-02-20 12:00 |
14:55:11.06 |
+05:50:13.1 |
HIP 73004 |
10.69 |
| 2026-02-21 00:00 |
14:54:56.50 |
+05:50:42.9 |
HIP 73004 |
10.85 |
| 2026-02-21 12:00 |
14:54:41.73 |
+05:51:13.2 |
HIP 73004 |
12.18 |
| 2026-02-22 00:00 |
14:54:26.76 |
+05:51:44.0 |
HIP 73004 |
14.41 |
| 2026-02-22 12:00 |
14:54:11.59 |
+05:52:15.1 |
HIP 73004 |
17.22 |
| 2026-02-23 00:00 |
14:53:56.20 |
+05:52:46.8 |
HIP 73004 |
20.40 |
| 2026-02-23 12:00 |
14:53:40.62 |
+05:53:18.8 |
HIP 72869 |
21.20 |
| 2026-02-24 00:00 |
14:53:24.83 |
+05:53:51.2 |
HIP 72869 |
20.99 |