| Parameter |
Value |
| Designation |
C/2025 F1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2025-04-20T11:22:51.692160Z |
| Orbit solution date (soln_date, UTC) |
2025-06-30T18:47:30Z |
| Obs used |
69 |
| NEO |
- |
| M1 |
15.800 |
| K1 |
44.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-03-22T00:57:23.299200Z |
| Discovery magnitude (MPC) |
19.16 c |
| Discovery observatory (MPC) |
W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-04-03.0000000 |
| e |
0.99629808 |
| q (au) |
1.069969 |
| a (au) |
289.030892 |
| i (deg) |
109.235882 |
| Ω (om, deg) |
122.704828 |
| ω (w, deg) |
334.230510 |
| M (ma, deg) |
359.996495 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.487 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.487 |
| n |
6.000 |
| gf |
0.998 |
| gb |
-1.000 |
| k |
0.800 |
| 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 |
22:35:45.71 |
+60:46:50.9 |
HIP 111469 |
6.16 |
| 2026-05-12 12:00 |
22:35:46.49 |
+60:50:40.1 |
HIP 111469 |
5.72 |
| 2026-05-13 00:00 |
22:35:46.93 |
+60:54:29.5 |
HIP 111469 |
7.49 |
| 2026-05-13 12:00 |
22:35:47.03 |
+60:58:18.9 |
HIP 111469 |
10.41 |
| 2026-05-14 00:00 |
22:35:46.78 |
+61:02:08.5 |
HIP 111469 |
13.76 |
| 2026-05-14 12:00 |
22:35:46.19 |
+61:05:58.2 |
HIP 111469 |
17.30 |
| 2026-05-15 00:00 |
22:35:45.25 |
+61:09:48.0 |
HIP 111469 |
20.94 |
| 2026-05-15 12:00 |
22:35:43.96 |
+61:13:37.9 |
HIP 111469 |
24.62 |
| 2026-05-16 00:00 |
22:35:42.31 |
+61:17:27.8 |
HIP 111469 |
28.34 |
| 2026-05-16 12:00 |
22:35:40.31 |
+61:21:17.7 |
HIP 111379 |
28.42 |
| 2026-05-17 00:00 |
22:35:37.94 |
+61:25:07.6 |
HIP 111379 |
24.90 |
| 2026-05-17 12:00 |
22:35:35.22 |
+61:28:57.4 |
HIP 111379 |
21.48 |
| 2026-05-18 00:00 |
22:35:32.13 |
+61:32:47.3 |
HIP 111379 |
18.20 |
| 2026-05-18 12:00 |
22:35:28.68 |
+61:36:37.0 |
HIP 111379 |
15.16 |
| 2026-05-19 00:00 |
22:35:24.86 |
+61:40:26.7 |
HIP 111379 |
12.53 |
| 2026-05-19 12:00 |
22:35:20.67 |
+61:44:16.3 |
HIP 111379 |
10.63 |
| 2026-05-20 00:00 |
22:35:16.10 |
+61:48:05.7 |
HIP 111379 |
9.91 |
| 2026-05-20 12:00 |
22:35:11.16 |
+61:51:54.9 |
HIP 111379 |
10.59 |
| 2026-05-21 00:00 |
22:35:05.85 |
+61:55:44.0 |
HIP 111379 |
12.47 |
| 2026-05-21 12:00 |
22:35:00.15 |
+61:59:32.9 |
HIP 111305 |
14.88 |
| 2026-05-22 00:00 |
22:34:54.07 |
+62:03:21.5 |
HIP 111305 |
15.50 |
| 2026-05-22 12:00 |
22:34:47.61 |
+62:07:09.9 |
HIP 111305 |
16.98 |
| 2026-05-23 00:00 |
22:34:40.76 |
+62:10:58.0 |
HIP 111305 |
19.11 |
| 2026-05-23 12:00 |
22:34:33.53 |
+62:14:45.9 |
HIP 111305 |
21.71 |
| 2026-05-24 00:00 |
22:34:25.91 |
+62:18:33.4 |
HIP 111706 |
24.27 |
| 2026-05-24 12:00 |
22:34:17.89 |
+62:22:20.6 |
HIP 111706 |
26.57 |
| 2026-05-25 00:00 |
22:34:09.48 |
+62:26:07.4 |
HIP 111706 |
29.25 |
| 2026-05-25 12:00 |
22:34:00.68 |
+62:29:53.9 |
HIP 111706 |
32.20 |
| 2026-05-26 00:00 |
22:33:51.47 |
+62:33:39.9 |
HIP 111706 |
35.37 |
| 2026-05-26 12:00 |
22:33:41.87 |
+62:37:25.5 |
HIP 111221 |
35.97 |
| 2026-05-27 00:00 |
22:33:31.87 |
+62:41:10.7 |
HIP 111221 |
32.05 |
| 2026-05-27 12:00 |
22:33:21.46 |
+62:44:55.4 |
HIP 111221 |
28.12 |
| 2026-05-28 00:00 |
22:33:10.64 |
+62:48:39.6 |
HIP 111221 |
24.18 |
| 2026-05-28 12:00 |
22:32:59.42 |
+62:52:23.3 |
HIP 111221 |
20.24 |
| 2026-05-29 00:00 |
22:32:47.78 |
+62:56:06.5 |
HIP 111221 |
16.29 |
| 2026-05-29 12:00 |
22:32:35.73 |
+62:59:49.1 |
HIP 111221 |
12.34 |
| 2026-05-30 00:00 |
22:32:23.27 |
+63:03:31.1 |
HIP 111221 |
8.38 |
| 2026-05-30 12:00 |
22:32:10.40 |
+63:07:12.5 |
HIP 111221 |
4.43 |
| 2026-05-31 00:00 |
22:31:57.10 |
+63:10:53.3 |
HIP 111221 |
0.75 |
| 2026-05-31 12:00 |
22:31:43.38 |
+63:14:33.4 |
HIP 111221 |
3.63 |
| 2026-06-01 00:00 |
22:31:29.24 |
+63:18:12.8 |
HIP 111221 |
7.59 |
| 2026-06-01 12:00 |
22:31:14.68 |
+63:21:51.6 |
HIP 111166 |
9.50 |
| 2026-06-02 00:00 |
22:30:59.68 |
+63:25:29.6 |
HIP 111166 |
6.13 |