| 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) |
| 2026-03-26 00:00 |
19:58:45.59 |
-27:49:39.4 |
HIP 98127 |
31.28 |
| 2026-03-26 12:00 |
19:59:15.23 |
-27:49:05.4 |
HIP 98284 |
37.21 |
| 2026-03-27 00:00 |
19:59:44.68 |
-27:48:31.9 |
HIP 98688 |
39.12 |
| 2026-03-27 12:00 |
20:00:13.93 |
-27:47:58.8 |
HIP 98688 |
32.64 |
| 2026-03-28 00:00 |
20:00:42.99 |
-27:47:26.1 |
HIP 98688 |
26.22 |
| 2026-03-28 12:00 |
20:01:11.85 |
-27:46:53.9 |
HIP 98688 |
19.86 |
| 2026-03-29 00:00 |
20:01:40.52 |
-27:46:22.1 |
HIP 98688 |
13.58 |
| 2026-03-29 12:00 |
20:02:08.99 |
-27:45:50.8 |
HIP 98688 |
7.49 |
| 2026-03-30 00:00 |
20:02:37.26 |
-27:45:19.9 |
HIP 98688 |
2.78 |
| 2026-03-30 12:00 |
20:03:05.34 |
-27:44:49.5 |
HIP 98688 |
6.15 |
| 2026-03-31 00:00 |
20:03:33.21 |
-27:44:19.6 |
HIP 98849 |
11.59 |
| 2026-03-31 12:00 |
20:04:00.89 |
-27:43:50.2 |
HIP 98849 |
5.55 |
| 2026-04-01 00:00 |
20:04:28.36 |
-27:43:21.2 |
HIP 98849 |
1.62 |
| 2026-04-01 12:00 |
20:04:55.63 |
-27:42:52.8 |
HIP 98849 |
6.94 |
| 2026-04-02 00:00 |
20:05:22.70 |
-27:42:24.9 |
HIP 98933 |
6.38 |
| 2026-04-02 12:00 |
20:05:49.56 |
-27:41:57.5 |
HIP 98933 |
9.76 |
| 2026-04-03 00:00 |
20:06:16.22 |
-27:41:30.6 |
HIP 98933 |
14.82 |
| 2026-04-03 12:00 |
20:06:42.67 |
-27:41:04.2 |
HIP 98933 |
20.30 |
| 2026-04-04 00:00 |
20:07:08.92 |
-27:40:38.4 |
HIP 98933 |
25.90 |
| 2026-04-04 12:00 |
20:07:34.95 |
-27:40:13.2 |
HIP 99313 |
26.26 |
| 2026-04-05 00:00 |
20:08:00.78 |
-27:39:48.5 |
HIP 99313 |
20.63 |
| 2026-04-05 12:00 |
20:08:26.40 |
-27:39:24.4 |
HIP 99313 |
15.12 |
| 2026-04-06 00:00 |
20:08:51.80 |
-27:39:00.9 |
HIP 99313 |
9.85 |
| 2026-04-06 12:00 |
20:09:17.00 |
-27:38:38.0 |
HIP 99313 |
5.42 |
| 2026-04-07 00:00 |
20:09:41.97 |
-27:38:15.6 |
HIP 99313 |
4.90 |
| 2026-04-07 12:00 |
20:10:06.74 |
-27:37:53.9 |
HIP 99363 |
3.91 |
| 2026-04-08 00:00 |
20:10:31.28 |
-27:37:32.8 |
HIP 99363 |
7.16 |
| 2026-04-08 12:00 |
20:10:55.61 |
-27:37:12.3 |
HIP 99363 |
12.06 |
| 2026-04-09 00:00 |
20:11:19.72 |
-27:36:52.4 |
HIP 99363 |
17.21 |
| 2026-04-09 12:00 |
20:11:43.61 |
-27:36:33.2 |
HIP 99499 |
16.99 |
| 2026-04-10 00:00 |
20:12:07.28 |
-27:36:14.6 |
HIP 99499 |
18.10 |
| 2026-04-10 12:00 |
20:12:30.73 |
-27:35:56.7 |
HIP 99499 |
20.52 |
| 2026-04-11 00:00 |
20:12:53.96 |
-27:35:39.5 |
HIP 99499 |
23.83 |
| 2026-04-11 12:00 |
20:13:16.96 |
-27:35:22.9 |
HIP 99499 |
27.67 |
| 2026-04-12 00:00 |
20:13:39.73 |
-27:35:07.0 |
HIP 99499 |
31.83 |
| 2026-04-12 12:00 |
20:14:02.28 |
-27:34:51.8 |
HIP 99932 |
33.67 |
| 2026-04-13 00:00 |
20:14:24.59 |
-27:34:37.2 |
HIP 99932 |
28.74 |
| 2026-04-13 12:00 |
20:14:46.68 |
-27:34:23.4 |
HIP 99932 |
23.87 |
| 2026-04-14 00:00 |
20:15:08.54 |
-27:34:10.3 |
HIP 99932 |
19.07 |
| 2026-04-14 12:00 |
20:15:30.16 |
-27:33:58.0 |
HIP 99932 |
14.34 |
| 2026-04-15 00:00 |
20:15:51.55 |
-27:33:46.3 |
HIP 99932 |
9.74 |
| 2026-04-15 12:00 |
20:16:12.71 |
-27:33:35.4 |
HIP 99932 |
5.42 |
| 2026-04-16 00:00 |
20:16:33.63 |
-27:33:25.3 |
HIP 99932 |
2.80 |