| 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) |
| 2026-09-20 00:00 |
18:45:59.50 |
+62:10:23.6 |
HIP 91921 |
18.18 |
| 2026-09-20 12:00 |
18:45:58.98 |
+62:07:32.5 |
HIP 91921 |
16.04 |
| 2026-09-21 00:00 |
18:45:58.70 |
+62:04:41.2 |
HIP 91921 |
14.17 |
| 2026-09-21 12:00 |
18:45:58.64 |
+62:01:49.6 |
HIP 91921 |
12.70 |
| 2026-09-22 00:00 |
18:45:58.81 |
+61:58:57.9 |
HIP 91921 |
11.77 |
| 2026-09-22 12:00 |
18:45:59.21 |
+61:56:06.0 |
HIP 91921 |
11.53 |
| 2026-09-23 00:00 |
18:45:59.83 |
+61:53:14.0 |
HIP 91921 |
12.02 |
| 2026-09-23 12:00 |
18:46:00.67 |
+61:50:21.8 |
HIP 91921 |
13.15 |
| 2026-09-24 00:00 |
18:46:01.74 |
+61:47:29.5 |
HIP 91921 |
14.78 |
| 2026-09-24 12:00 |
18:46:03.03 |
+61:44:37.1 |
HIP 91921 |
16.78 |
| 2026-09-25 00:00 |
18:46:04.54 |
+61:41:44.5 |
HIP 91921 |
19.01 |
| 2026-09-25 12:00 |
18:46:06.27 |
+61:38:51.9 |
HIP 91921 |
21.42 |
| 2026-09-26 00:00 |
18:46:08.22 |
+61:35:59.2 |
HIP 91921 |
23.95 |
| 2026-09-26 12:00 |
18:46:10.38 |
+61:33:06.5 |
HIP 91921 |
26.57 |
| 2026-09-27 00:00 |
18:46:12.77 |
+61:30:13.6 |
HIP 91921 |
29.25 |
| 2026-09-27 12:00 |
18:46:15.36 |
+61:27:20.8 |
HIP 91915 |
28.22 |
| 2026-09-28 00:00 |
18:46:18.18 |
+61:24:27.9 |
HIP 91915 |
25.96 |
| 2026-09-28 12:00 |
18:46:21.20 |
+61:21:35.0 |
HIP 91915 |
23.85 |
| 2026-09-29 00:00 |
18:46:24.44 |
+61:18:42.2 |
HIP 91915 |
21.94 |
| 2026-09-29 12:00 |
18:46:27.90 |
+61:15:49.3 |
HIP 91915 |
20.29 |
| 2026-09-30 00:00 |
18:46:31.56 |
+61:12:56.4 |
HIP 91915 |
18.97 |
| 2026-09-30 12:00 |
18:46:35.43 |
+61:10:03.6 |
HIP 91915 |
18.05 |
| 2026-10-01 00:00 |
18:46:39.51 |
+61:07:10.9 |
HIP 91915 |
17.61 |
| 2026-10-01 12:00 |
18:46:43.80 |
+61:04:18.2 |
HIP 91915 |
17.66 |
| 2026-10-02 00:00 |
18:46:48.29 |
+61:01:25.6 |
HIP 92149 |
17.64 |
| 2026-10-02 12:00 |
18:46:52.99 |
+60:58:33.0 |
HIP 92149 |
14.76 |
| 2026-10-03 00:00 |
18:46:57.90 |
+60:55:40.6 |
HIP 92149 |
11.90 |
| 2026-10-03 12:00 |
18:47:03.01 |
+60:52:48.3 |
HIP 92149 |
9.09 |
| 2026-10-04 00:00 |
18:47:08.32 |
+60:49:56.1 |
HIP 92149 |
6.42 |
| 2026-10-04 12:00 |
18:47:13.84 |
+60:47:04.0 |
HIP 92149 |
4.15 |
| 2026-10-05 00:00 |
18:47:19.55 |
+60:44:12.1 |
HIP 92149 |
3.28 |
| 2026-10-05 12:00 |
18:47:25.47 |
+60:41:20.3 |
HIP 92149 |
4.68 |
| 2026-10-06 00:00 |
18:47:31.59 |
+60:38:28.8 |
HIP 92149 |
7.12 |
| 2026-10-06 12:00 |
18:47:37.90 |
+60:35:37.4 |
HIP 92149 |
9.85 |
| 2026-10-07 00:00 |
18:47:44.41 |
+60:32:46.2 |
HIP 92149 |
12.70 |
| 2026-10-07 12:00 |
18:47:51.12 |
+60:29:55.2 |
HIP 92149 |
15.60 |
| 2026-10-08 00:00 |
18:47:58.02 |
+60:27:04.5 |
HIP 92149 |
18.53 |
| 2026-10-08 12:00 |
18:48:05.12 |
+60:24:14.0 |
HIP 92149 |
21.48 |
| 2026-10-09 00:00 |
18:48:12.41 |
+60:21:23.8 |
HIP 92149 |
24.44 |
| 2026-10-09 12:00 |
18:48:19.89 |
+60:18:33.8 |
HIP 92555 |
25.62 |
| 2026-10-10 00:00 |
18:48:27.56 |
+60:15:44.1 |
HIP 92555 |
25.73 |
| 2026-10-10 12:00 |
18:48:35.42 |
+60:12:54.7 |
HIP 92555 |
26.15 |
| 2026-10-11 00:00 |
18:48:43.47 |
+60:10:05.6 |
HIP 92555 |
26.88 |