C/2025 F1 (ATLAS)
| 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) |
| 2026-02-03 00:00 |
21:16:47.05 |
+54:06:56.9 |
HIP 105064 |
7.42 |
| 2026-02-03 12:00 |
21:17:29.51 |
+54:05:51.6 |
HIP 105064 |
7.23 |
| 2026-02-04 00:00 |
21:18:11.79 |
+54:04:49.1 |
HIP 105182 |
6.03 |
| 2026-02-04 12:00 |
21:18:53.88 |
+54:03:49.4 |
HIP 105182 |
7.69 |
| 2026-02-05 00:00 |
21:19:35.79 |
+54:02:52.4 |
HIP 105309 |
5.94 |
| 2026-02-05 12:00 |
21:20:17.52 |
+54:01:58.2 |
HIP 105309 |
6.84 |
| 2026-02-06 00:00 |
21:20:59.06 |
+54:01:06.6 |
HIP 105309 |
11.61 |
| 2026-02-06 12:00 |
21:21:40.43 |
+54:00:17.8 |
HIP 105559 |
16.36 |
| 2026-02-07 00:00 |
21:22:21.61 |
+53:59:31.6 |
HIP 105559 |
14.65 |
| 2026-02-07 12:00 |
21:23:02.61 |
+53:58:48.1 |
HIP 105559 |
15.31 |
| 2026-02-08 00:00 |
21:23:43.44 |
+53:58:07.3 |
HIP 105559 |
18.04 |
| 2026-02-08 12:00 |
21:24:24.08 |
+53:57:29.2 |
HIP 105559 |
22.07 |
| 2026-02-09 00:00 |
21:25:04.55 |
+53:56:53.6 |
HIP 105559 |
26.79 |
| 2026-02-09 12:00 |
21:25:44.84 |
+53:56:20.7 |
HIP 106073 |
31.00 |
| 2026-02-10 00:00 |
21:26:24.95 |
+53:55:50.5 |
HIP 106073 |
25.21 |
| 2026-02-10 12:00 |
21:27:04.89 |
+53:55:22.8 |
HIP 106073 |
19.55 |
| 2026-02-11 00:00 |
21:27:44.65 |
+53:54:57.7 |
HIP 106073 |
14.13 |
| 2026-02-11 12:00 |
21:28:24.24 |
+53:54:35.2 |
HIP 106073 |
9.34 |
| 2026-02-12 00:00 |
21:29:03.65 |
+53:54:15.2 |
HIP 106073 |
6.62 |
| 2026-02-12 12:00 |
21:29:42.89 |
+53:53:57.9 |
HIP 106073 |
8.27 |
| 2026-02-13 00:00 |
21:30:21.96 |
+53:53:43.0 |
HIP 106245 |
7.18 |
| 2026-02-13 12:00 |
21:31:00.85 |
+53:53:30.7 |
HIP 106245 |
2.03 |
| 2026-02-14 00:00 |
21:31:39.56 |
+53:53:20.9 |
HIP 106245 |
4.69 |
| 2026-02-14 12:00 |
21:32:18.11 |
+53:53:13.6 |
HIP 106366 |
5.50 |
| 2026-02-15 00:00 |
21:32:56.48 |
+53:53:08.7 |
HIP 106366 |
5.64 |
| 2026-02-15 12:00 |
21:33:34.68 |
+53:53:06.4 |
HIP 106366 |
9.86 |
| 2026-02-16 00:00 |
21:34:12.70 |
+53:53:06.5 |
HIP 106366 |
15.03 |
| 2026-02-16 12:00 |
21:34:50.56 |
+53:53:09.1 |
HIP 106366 |
20.42 |
| 2026-02-17 00:00 |
21:35:28.24 |
+53:53:14.1 |
HIP 106771 |
21.34 |
| 2026-02-17 12:00 |
21:36:05.75 |
+53:53:21.5 |
HIP 106771 |
16.48 |
| 2026-02-18 00:00 |
21:36:43.09 |
+53:53:31.3 |
HIP 106771 |
12.18 |
| 2026-02-18 12:00 |
21:37:20.25 |
+53:53:43.5 |
HIP 106771 |
9.22 |
| 2026-02-19 00:00 |
21:37:57.25 |
+53:53:58.1 |
HIP 106771 |
8.98 |
| 2026-02-19 12:00 |
21:38:34.07 |
+53:54:15.1 |
HIP 106860 |
10.87 |
| 2026-02-20 00:00 |
21:39:10.72 |
+53:54:34.4 |
HIP 106980 |
8.24 |
| 2026-02-20 12:00 |
21:39:47.20 |
+53:54:56.0 |
HIP 106980 |
3.81 |
| 2026-02-21 00:00 |
21:40:23.50 |
+53:55:20.0 |
HIP 106980 |
4.32 |
| 2026-02-21 12:00 |
21:40:59.64 |
+53:55:46.3 |
HIP 107012 |
7.95 |
| 2026-02-22 00:00 |
21:41:35.60 |
+53:56:14.8 |
HIP 107012 |
11.86 |
| 2026-02-22 12:00 |
21:42:11.39 |
+53:56:45.6 |
HIP 107211 |
12.35 |
| 2026-02-23 00:00 |
21:42:47.01 |
+53:57:18.7 |
HIP 107211 |
11.29 |
| 2026-02-23 12:00 |
21:43:22.45 |
+53:57:54.0 |
HIP 107211 |
12.61 |
| 2026-02-24 00:00 |
21:43:57.73 |
+53:58:31.6 |
HIP 107211 |
15.69 |