| Parameter |
Value |
| Designation |
C/2024 C4 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2024-01-30T04:46:56.107200Z |
| Orbit solution date (soln_date, UTC) |
2024-08-18T18:42:14Z |
| Obs used |
545 |
| NEO |
- |
| M1 |
14.700 |
| K1 |
9.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2024-02-14T01:57:11.318400Z |
| Discovery magnitude (MPC) |
17.45 o |
| Discovery observatory (MPC) |
M22 · ATLAS South Africa, Sutherland |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2024-04-20.0000000 |
| e |
0.98249391 |
| q (au) |
1.471267 |
| a (au) |
84.043133 |
| i (deg) |
79.287579 |
| Ω (om, deg) |
220.685068 |
| ω (w, deg) |
321.524084 |
| M (ma, deg) |
0.103363 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.966 + 4.002\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.966 |
| n |
4.002 |
| gf |
1.000 |
| gb |
-0.751 |
| k |
0.989 |
| 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) |
| 2026-05-12 00:00 |
20:02:47.44 |
+62:28:35.5 |
HIP 98557 |
12.05 |
| 2026-05-12 12:00 |
20:02:41.06 |
+62:31:50.2 |
HIP 98557 |
13.15 |
| 2026-05-13 00:00 |
20:02:34.43 |
+62:35:04.1 |
HIP 98557 |
14.90 |
| 2026-05-13 12:00 |
20:02:27.54 |
+62:38:17.2 |
HIP 98557 |
17.10 |
| 2026-05-14 00:00 |
20:02:20.40 |
+62:41:29.4 |
HIP 98803 |
17.99 |
| 2026-05-14 12:00 |
20:02:13.02 |
+62:44:40.7 |
HIP 98803 |
16.26 |
| 2026-05-15 00:00 |
20:02:05.38 |
+62:47:51.1 |
HIP 98803 |
15.10 |
| 2026-05-15 12:00 |
20:01:57.48 |
+62:51:00.6 |
HIP 98803 |
14.64 |
| 2026-05-16 00:00 |
20:01:49.34 |
+62:54:09.2 |
HIP 98803 |
14.93 |
| 2026-05-16 12:00 |
20:01:40.94 |
+62:57:16.8 |
HIP 98803 |
15.92 |
| 2026-05-17 00:00 |
20:01:32.29 |
+63:00:23.4 |
HIP 98803 |
17.50 |
| 2026-05-17 12:00 |
20:01:23.39 |
+63:03:29.1 |
HIP 98803 |
19.52 |
| 2026-05-18 00:00 |
20:01:14.24 |
+63:06:33.8 |
HIP 98803 |
21.85 |
| 2026-05-18 12:00 |
20:01:04.84 |
+63:09:37.5 |
HIP 98613 |
23.51 |
| 2026-05-19 00:00 |
20:00:55.18 |
+63:12:40.1 |
HIP 98613 |
20.80 |
| 2026-05-19 12:00 |
20:00:45.28 |
+63:15:41.7 |
HIP 98613 |
18.29 |
| 2026-05-20 00:00 |
20:00:35.12 |
+63:18:42.3 |
HIP 98613 |
16.06 |
| 2026-05-20 12:00 |
20:00:24.72 |
+63:21:41.8 |
HIP 98613 |
14.24 |
| 2026-05-21 00:00 |
20:00:14.07 |
+63:24:40.2 |
HIP 98613 |
13.01 |
| 2026-05-21 12:00 |
20:00:03.16 |
+63:27:37.5 |
HIP 98308 |
11.43 |
| 2026-05-22 00:00 |
19:59:52.01 |
+63:30:33.7 |
HIP 98308 |
9.40 |
| 2026-05-22 12:00 |
19:59:40.61 |
+63:33:28.7 |
HIP 98308 |
8.13 |
| 2026-05-23 00:00 |
19:59:28.97 |
+63:36:22.7 |
HIP 98308 |
7.98 |
| 2026-05-23 12:00 |
19:59:17.08 |
+63:39:15.4 |
HIP 98419 |
7.95 |
| 2026-05-24 00:00 |
19:59:04.94 |
+63:42:07.0 |
HIP 98419 |
6.50 |
| 2026-05-24 12:00 |
19:58:52.56 |
+63:44:57.5 |
HIP 98419 |
6.45 |
| 2026-05-25 00:00 |
19:58:39.93 |
+63:47:46.7 |
HIP 98419 |
7.82 |
| 2026-05-25 12:00 |
19:58:27.06 |
+63:50:34.7 |
HIP 98419 |
10.03 |
| 2026-05-26 00:00 |
19:58:13.95 |
+63:53:21.6 |
HIP 98419 |
12.66 |
| 2026-05-26 12:00 |
19:58:00.60 |
+63:56:07.1 |
HIP 98419 |
15.47 |
| 2026-05-27 00:00 |
19:57:47.00 |
+63:58:51.5 |
HIP 98419 |
18.39 |
| 2026-05-27 12:00 |
19:57:33.16 |
+64:01:34.5 |
HIP 98419 |
21.37 |
| 2026-05-28 00:00 |
19:57:19.09 |
+64:04:16.4 |
HIP 98419 |
24.38 |
| 2026-05-28 12:00 |
19:57:04.78 |
+64:06:56.9 |
HIP 98419 |
27.41 |
| 2026-05-29 00:00 |
19:56:50.22 |
+64:09:36.1 |
HIP 97831 |
26.44 |
| 2026-05-29 12:00 |
19:56:35.44 |
+64:12:14.0 |
HIP 97831 |
24.85 |
| 2026-05-30 00:00 |
19:56:20.41 |
+64:14:50.6 |
HIP 97831 |
23.53 |
| 2026-05-30 12:00 |
19:56:05.15 |
+64:17:25.9 |
HIP 97831 |
22.53 |
| 2026-05-31 00:00 |
19:55:49.66 |
+64:19:59.8 |
HIP 97831 |
21.90 |
| 2026-05-31 12:00 |
19:55:33.93 |
+64:22:32.4 |
HIP 97988 |
21.28 |
| 2026-06-01 00:00 |
19:55:17.97 |
+64:25:03.5 |
HIP 97988 |
18.47 |
| 2026-06-01 12:00 |
19:55:01.79 |
+64:27:33.3 |
HIP 97988 |
15.77 |
| 2026-06-02 00:00 |
19:54:45.37 |
+64:30:01.7 |
HIP 97988 |
13.25 |