| 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 |
1.000 |
| 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) |
| 2026-07-29 00:00 |
21:17:02.12 |
+66:53:12.4 |
HIP 105122 |
15.34 |
| 2026-07-29 12:00 |
21:16:07.88 |
+66:52:09.6 |
HIP 105122 |
16.52 |
| 2026-07-30 00:00 |
21:15:13.67 |
+66:51:03.0 |
HIP 105122 |
19.19 |
| 2026-07-30 12:00 |
21:14:19.49 |
+66:49:52.7 |
HIP 104562 |
21.82 |
| 2026-07-31 00:00 |
21:13:25.37 |
+66:48:38.8 |
HIP 104562 |
16.40 |
| 2026-07-31 12:00 |
21:12:31.31 |
+66:47:21.1 |
HIP 104562 |
10.99 |
| 2026-08-01 00:00 |
21:11:37.31 |
+66:45:59.6 |
HIP 104562 |
5.71 |
| 2026-08-01 12:00 |
21:10:43.39 |
+66:44:34.5 |
HIP 104562 |
2.14 |
| 2026-08-02 00:00 |
21:09:49.56 |
+66:43:05.7 |
HIP 104562 |
6.09 |
| 2026-08-02 12:00 |
21:08:55.82 |
+66:41:33.1 |
HIP 104562 |
11.43 |
| 2026-08-03 00:00 |
21:08:02.20 |
+66:39:56.8 |
HIP 104562 |
16.90 |
| 2026-08-03 12:00 |
21:07:08.68 |
+66:38:16.9 |
HIP 104562 |
22.42 |
| 2026-08-04 00:00 |
21:06:15.30 |
+66:36:33.2 |
HIP 104562 |
27.96 |
| 2026-08-04 12:00 |
21:05:22.04 |
+66:34:45.8 |
HIP 103758 |
24.07 |
| 2026-08-05 00:00 |
21:04:28.93 |
+66:32:54.8 |
HIP 103758 |
20.00 |
| 2026-08-05 12:00 |
21:03:35.98 |
+66:31:00.0 |
HIP 103758 |
16.86 |
| 2026-08-06 00:00 |
21:02:43.18 |
+66:29:01.6 |
HIP 103758 |
15.25 |
| 2026-08-06 12:00 |
21:01:50.56 |
+66:26:59.5 |
HIP 103758 |
15.67 |
| 2026-08-07 00:00 |
21:00:58.11 |
+66:24:53.8 |
HIP 103758 |
17.99 |
| 2026-08-07 12:00 |
21:00:05.86 |
+66:22:44.4 |
HIP 103758 |
21.61 |
| 2026-08-08 00:00 |
20:59:13.80 |
+66:20:31.4 |
HIP 103758 |
26.00 |
| 2026-08-08 12:00 |
20:58:21.95 |
+66:18:14.8 |
HIP 103758 |
30.84 |
| 2026-08-09 00:00 |
20:57:30.31 |
+66:15:54.5 |
HIP 103357 |
27.08 |
| 2026-08-09 12:00 |
20:56:38.90 |
+66:13:30.7 |
HIP 103357 |
23.90 |
| 2026-08-10 00:00 |
20:55:47.72 |
+66:11:03.2 |
HIP 103357 |
21.73 |
| 2026-08-10 12:00 |
20:54:56.79 |
+66:08:32.2 |
HIP 103014 |
18.40 |
| 2026-08-11 00:00 |
20:54:06.10 |
+66:05:57.6 |
HIP 103014 |
15.77 |
| 2026-08-11 12:00 |
20:53:15.67 |
+66:03:19.5 |
HIP 103014 |
15.03 |
| 2026-08-12 00:00 |
20:52:25.50 |
+66:00:37.9 |
HIP 103014 |
16.45 |
| 2026-08-12 12:00 |
20:51:35.61 |
+65:57:52.7 |
HIP 103014 |
19.57 |
| 2026-08-13 00:00 |
20:50:46.00 |
+65:55:04.1 |
HIP 103014 |
23.75 |
| 2026-08-13 12:00 |
20:49:56.68 |
+65:52:12.0 |
HIP 103014 |
28.52 |
| 2026-08-14 00:00 |
20:49:07.66 |
+65:49:16.5 |
HIP 102448 |
25.46 |
| 2026-08-14 12:00 |
20:48:18.94 |
+65:46:17.6 |
HIP 102448 |
19.64 |
| 2026-08-15 00:00 |
20:47:30.53 |
+65:43:15.3 |
HIP 102448 |
13.82 |
| 2026-08-15 12:00 |
20:46:42.44 |
+65:40:09.6 |
HIP 102448 |
7.99 |
| 2026-08-16 00:00 |
20:45:54.67 |
+65:37:00.5 |
HIP 102448 |
2.18 |
| 2026-08-16 12:00 |
20:45:07.24 |
+65:33:48.2 |
HIP 102448 |
3.76 |
| 2026-08-17 00:00 |
20:44:20.14 |
+65:30:32.5 |
HIP 102448 |
9.61 |
| 2026-08-17 12:00 |
20:43:33.38 |
+65:27:13.6 |
HIP 102448 |
15.48 |
| 2026-08-18 00:00 |
20:42:46.98 |
+65:23:51.4 |
HIP 102448 |
21.37 |
| 2026-08-18 12:00 |
20:42:00.92 |
+65:20:26.1 |
HIP 101938 |
19.95 |
| 2026-08-19 00:00 |
20:41:15.23 |
+65:16:57.5 |
HIP 101938 |
14.04 |