P/2025 C1 (ATLAS)
| Parameter |
Value |
| Designation |
P/2025 C1 (ATLAS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2025-02-06T12:52:50.154240Z |
| Orbit solution date (soln_date, UTC) |
2025-09-30T13:39:40Z |
| Obs used |
385 |
| NEO |
- |
| M1 |
6.900 |
| K1 |
20.250 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2025-02-02T15:11:23.596800Z |
| Discovery magnitude (MPC) |
18.47 c |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-02-27.0000000 |
| e |
0.34537178 |
| q (au) |
2.746051 |
| a (au) |
4.194826 |
| i (deg) |
7.517505 |
| Ω (om, deg) |
9.104185 |
| ω (w, deg) |
186.793260 |
| M (ma, deg) |
2.347518 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.324 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.324 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.997 |
| k |
1.000 |
| 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 |
18:54:19.96 |
-28:56:53.1 |
HIP 92805 |
15.04 |
| 2026-02-03 12:00 |
18:55:04.43 |
-28:56:22.6 |
HIP 92805 |
15.52 |
| 2026-02-04 00:00 |
18:55:48.81 |
-28:55:51.7 |
HIP 92870 |
17.65 |
| 2026-02-04 12:00 |
18:56:33.08 |
-28:55:20.3 |
HIP 92870 |
22.80 |
| 2026-02-05 00:00 |
18:57:17.24 |
-28:54:48.5 |
HIP 93123 |
15.73 |
| 2026-02-05 12:00 |
18:58:01.31 |
-28:54:16.3 |
HIP 93123 |
9.53 |
| 2026-02-06 00:00 |
18:58:45.27 |
-28:53:43.7 |
HIP 93123 |
10.98 |
| 2026-02-06 12:00 |
18:59:29.12 |
-28:53:10.6 |
HIP 93207 |
18.25 |
| 2026-02-07 00:00 |
19:00:12.87 |
-28:52:37.2 |
HIP 93375 |
15.22 |
| 2026-02-07 12:00 |
19:00:56.51 |
-28:52:03.4 |
HIP 93375 |
9.46 |
| 2026-02-08 00:00 |
19:01:40.04 |
-28:51:29.2 |
HIP 93375 |
11.42 |
| 2026-02-08 12:00 |
19:02:23.47 |
-28:50:54.6 |
HIP 93479 |
12.06 |
| 2026-02-09 00:00 |
19:03:06.78 |
-28:50:19.6 |
HIP 93500 |
13.92 |
| 2026-02-09 12:00 |
19:03:49.98 |
-28:49:44.3 |
HIP 93500 |
20.35 |
| 2026-02-10 00:00 |
19:04:33.08 |
-28:49:08.7 |
HIP 93769 |
22.54 |
| 2026-02-10 12:00 |
19:05:16.06 |
-28:48:32.6 |
HIP 93769 |
17.66 |
| 2026-02-11 00:00 |
19:05:58.93 |
-28:47:56.3 |
HIP 93769 |
17.13 |
| 2026-02-11 12:00 |
19:06:41.68 |
-28:47:19.6 |
HIP 93925 |
14.12 |
| 2026-02-12 00:00 |
19:07:24.32 |
-28:46:42.6 |
HIP 93925 |
8.62 |
| 2026-02-12 12:00 |
19:08:06.84 |
-28:46:05.3 |
HIP 94059 |
10.95 |
| 2026-02-13 00:00 |
19:08:49.25 |
-28:45:27.6 |
HIP 94059 |
1.83 |
| 2026-02-13 12:00 |
19:09:31.54 |
-28:44:49.7 |
HIP 94059 |
7.75 |
| 2026-02-14 00:00 |
19:10:13.70 |
-28:44:11.4 |
HIP 94176 |
8.12 |
| 2026-02-14 12:00 |
19:10:55.75 |
-28:43:32.9 |
HIP 94261 |
12.04 |
| 2026-02-15 00:00 |
19:11:37.68 |
-28:42:54.1 |
HIP 94261 |
12.24 |
| 2026-02-15 12:00 |
19:12:19.49 |
-28:42:15.1 |
HIP 94425 |
11.24 |
| 2026-02-16 00:00 |
19:13:01.18 |
-28:41:35.8 |
HIP 94425 |
4.98 |
| 2026-02-16 12:00 |
19:13:42.74 |
-28:40:56.2 |
HIP 94425 |
9.53 |
| 2026-02-17 00:00 |
19:14:24.17 |
-28:40:16.4 |
HIP 94425 |
17.97 |
| 2026-02-17 12:00 |
19:15:05.48 |
-28:39:36.3 |
HIP 94752 |
22.67 |
| 2026-02-18 00:00 |
19:15:46.67 |
-28:38:56.0 |
HIP 94752 |
13.68 |
| 2026-02-18 12:00 |
19:16:27.73 |
-28:38:15.5 |
HIP 94752 |
4.95 |
| 2026-02-19 00:00 |
19:17:08.65 |
-28:37:34.8 |
HIP 94752 |
4.99 |
| 2026-02-19 12:00 |
19:17:49.45 |
-28:36:53.9 |
HIP 94752 |
13.66 |
| 2026-02-20 00:00 |
19:18:30.12 |
-28:36:12.8 |
HIP 94985 |
15.22 |
| 2026-02-20 12:00 |
19:19:10.66 |
-28:35:31.5 |
HIP 94985 |
6.37 |
| 2026-02-21 00:00 |
19:19:51.07 |
-28:34:50.1 |
HIP 94985 |
2.95 |
| 2026-02-21 12:00 |
19:20:31.34 |
-28:34:08.4 |
HIP 94985 |
11.60 |
| 2026-02-22 00:00 |
19:21:11.48 |
-28:33:26.6 |
HIP 95182 |
13.56 |
| 2026-02-22 12:00 |
19:21:51.48 |
-28:32:44.7 |
HIP 95182 |
11.85 |
| 2026-02-23 00:00 |
19:22:31.35 |
-28:32:02.6 |
HIP 95278 |
7.11 |
| 2026-02-23 12:00 |
19:23:11.08 |
-28:31:20.3 |
HIP 95278 |
2.16 |
| 2026-02-24 00:00 |
19:23:50.68 |
-28:30:38.0 |
HIP 95278 |
10.56 |