| Parameter |
Value |
| Designation |
C/2024 G2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2025-06-13T13:03:03.144960Z |
| Orbit solution date (soln_date, UTC) |
2026-09-08T09:12:16Z |
| Obs used |
691 |
| NEO |
- |
| M1 |
6.700 |
| K1 |
11.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2024-04-08T07:54:38.131200Z |
| Discovery magnitude (MPC) |
18.63 o |
| Discovery observatory (MPC) |
W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-08-19.0000000 |
| e |
0.99264654 |
| q (au) |
5.348246 |
| a (au) |
727.309835 |
| i (deg) |
122.123851 |
| Ω (om, deg) |
171.397723 |
| ω (w, deg) |
328.739162 |
| M (ma, deg) |
0.003339 |
Magnitude
Scatter + Global Linear
$$
M_a = (2.899 + 5.912\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
2.899 |
| n |
5.912 |
| gf |
0.889 |
| gb |
-0.993 |
| k |
1.000 |
| δ90 |
8.559 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2024-04-08 |
2025-06-12 |
-4.1033 |
+2.737 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
11:22:47.28 |
+16:04:53.4 |
HIP 55603 |
10.76 |
| 2026-09-20 12:00 |
11:23:01.16 |
+16:05:34.4 |
HIP 55603 |
8.50 |
| 2026-09-21 00:00 |
11:23:15.03 |
+16:06:15.9 |
HIP 55603 |
7.21 |
| 2026-09-21 12:00 |
11:23:28.88 |
+16:06:57.9 |
HIP 55603 |
7.42 |
| 2026-09-22 00:00 |
11:23:42.72 |
+16:07:40.4 |
HIP 55603 |
9.02 |
| 2026-09-22 12:00 |
11:23:56.54 |
+16:08:23.3 |
HIP 55603 |
11.44 |
| 2026-09-23 00:00 |
11:24:10.34 |
+16:09:06.8 |
HIP 55690 |
12.33 |
| 2026-09-23 12:00 |
11:24:24.12 |
+16:09:50.8 |
HIP 55690 |
10.10 |
| 2026-09-24 00:00 |
11:24:37.88 |
+16:10:35.4 |
HIP 55690 |
8.64 |
| 2026-09-24 12:00 |
11:24:51.63 |
+16:11:20.4 |
HIP 55690 |
8.38 |
| 2026-09-25 00:00 |
11:25:05.35 |
+16:12:06.0 |
HIP 55690 |
9.40 |
| 2026-09-25 12:00 |
11:25:19.06 |
+16:12:52.1 |
HIP 55690 |
11.36 |
| 2026-09-26 00:00 |
11:25:32.74 |
+16:13:38.8 |
HIP 55765 |
13.77 |
| 2026-09-26 12:00 |
11:25:46.40 |
+16:14:26.1 |
HIP 55765 |
13.18 |
| 2026-09-27 00:00 |
11:26:00.03 |
+16:15:13.9 |
HIP 55765 |
13.41 |
| 2026-09-27 12:00 |
11:26:13.65 |
+16:16:02.3 |
HIP 55765 |
14.44 |
| 2026-09-28 00:00 |
11:26:27.23 |
+16:16:51.3 |
HIP 55765 |
16.11 |
| 2026-09-28 12:00 |
11:26:40.80 |
+16:17:40.8 |
HIP 55765 |
18.23 |
| 2026-09-29 00:00 |
11:26:54.34 |
+16:18:31.0 |
HIP 55765 |
20.68 |
| 2026-09-29 12:00 |
11:27:07.85 |
+16:19:21.7 |
HIP 55765 |
23.34 |
| 2026-09-30 00:00 |
11:27:21.34 |
+16:20:13.1 |
HIP 56043 |
26.15 |
| 2026-09-30 12:00 |
11:27:34.79 |
+16:21:05.1 |
HIP 56043 |
22.86 |
| 2026-10-01 00:00 |
11:27:48.22 |
+16:21:57.7 |
HIP 56043 |
19.59 |
| 2026-10-01 12:00 |
11:28:01.62 |
+16:22:50.9 |
HIP 56043 |
16.36 |
| 2026-10-02 00:00 |
11:28:15.00 |
+16:23:44.8 |
HIP 56043 |
13.19 |
| 2026-10-02 12:00 |
11:28:28.34 |
+16:24:39.3 |
HIP 56043 |
10.13 |
| 2026-10-03 00:00 |
11:28:41.65 |
+16:25:34.5 |
HIP 56043 |
7.33 |
| 2026-10-03 12:00 |
11:28:54.93 |
+16:26:30.3 |
HIP 56043 |
5.18 |
| 2026-10-04 00:00 |
11:29:08.17 |
+16:27:26.9 |
HIP 56043 |
4.71 |
| 2026-10-04 12:00 |
11:29:21.38 |
+16:28:24.1 |
HIP 56043 |
6.29 |
| 2026-10-05 00:00 |
11:29:34.56 |
+16:29:22.0 |
HIP 56043 |
8.88 |
| 2026-10-05 12:00 |
11:29:47.70 |
+16:30:20.6 |
HIP 56043 |
11.84 |
| 2026-10-06 00:00 |
11:30:00.81 |
+16:31:19.9 |
HIP 56043 |
14.93 |
| 2026-10-06 12:00 |
11:30:13.88 |
+16:32:19.9 |
HIP 56043 |
18.10 |
| 2026-10-07 00:00 |
11:30:26.92 |
+16:33:20.7 |
HIP 56043 |
21.30 |
| 2026-10-07 12:00 |
11:30:39.91 |
+16:34:22.2 |
HIP 56043 |
24.52 |
| 2026-10-08 00:00 |
11:30:52.87 |
+16:35:24.4 |
HIP 56276 |
22.56 |
| 2026-10-08 12:00 |
11:31:05.78 |
+16:36:27.4 |
HIP 56276 |
20.61 |
| 2026-10-09 00:00 |
11:31:18.66 |
+16:37:31.1 |
HIP 56276 |
19.04 |
| 2026-10-09 12:00 |
11:31:31.49 |
+16:38:35.6 |
HIP 56276 |
17.95 |
| 2026-10-10 00:00 |
11:31:44.28 |
+16:39:40.9 |
HIP 56276 |
17.42 |
| 2026-10-10 12:00 |
11:31:57.03 |
+16:40:47.0 |
HIP 56276 |
17.51 |
| 2026-10-11 00:00 |
11:32:09.73 |
+16:41:53.9 |
HIP 56276 |
18.20 |