| 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) |
| 2026-05-12 00:00 |
20:28:51.16 |
-27:43:49.9 |
HIP 100923 |
15.38 |
| 2026-05-12 12:00 |
20:28:58.14 |
-27:44:25.8 |
HIP 100923 |
16.90 |
| 2026-05-13 00:00 |
20:29:04.83 |
-27:45:02.6 |
HIP 100923 |
18.38 |
| 2026-05-13 12:00 |
20:29:11.23 |
-27:45:40.3 |
HIP 100923 |
19.81 |
| 2026-05-14 00:00 |
20:29:17.34 |
-27:46:18.9 |
HIP 100923 |
21.20 |
| 2026-05-14 12:00 |
20:29:23.16 |
-27:46:58.5 |
HIP 100923 |
22.54 |
| 2026-05-15 00:00 |
20:29:28.68 |
-27:47:39.0 |
HIP 100923 |
23.82 |
| 2026-05-15 12:00 |
20:29:33.91 |
-27:48:20.4 |
HIP 101250 |
24.73 |
| 2026-05-16 00:00 |
20:29:38.85 |
-27:49:02.7 |
HIP 101250 |
23.76 |
| 2026-05-16 12:00 |
20:29:43.48 |
-27:49:45.9 |
HIP 101250 |
22.90 |
| 2026-05-17 00:00 |
20:29:47.83 |
-27:50:30.1 |
HIP 101250 |
22.13 |
| 2026-05-17 12:00 |
20:29:51.88 |
-27:51:15.1 |
HIP 101250 |
21.47 |
| 2026-05-18 00:00 |
20:29:55.63 |
-27:52:01.1 |
HIP 101250 |
20.93 |
| 2026-05-18 12:00 |
20:29:59.08 |
-27:52:47.9 |
HIP 101250 |
20.50 |
| 2026-05-19 00:00 |
20:30:02.24 |
-27:53:35.6 |
HIP 101250 |
20.19 |
| 2026-05-19 12:00 |
20:30:05.10 |
-27:54:24.3 |
HIP 101250 |
19.99 |
| 2026-05-20 00:00 |
20:30:07.66 |
-27:55:13.8 |
HIP 101250 |
19.91 |
| 2026-05-20 12:00 |
20:30:09.92 |
-27:56:04.1 |
HIP 101250 |
19.94 |
| 2026-05-21 00:00 |
20:30:11.89 |
-27:56:55.4 |
HIP 101250 |
20.08 |
| 2026-05-21 12:00 |
20:30:13.55 |
-27:57:47.5 |
HIP 101250 |
20.32 |
| 2026-05-22 00:00 |
20:30:14.92 |
-27:58:40.4 |
HIP 101250 |
20.66 |
| 2026-05-22 12:00 |
20:30:15.99 |
-27:59:34.2 |
HIP 101283 |
20.45 |
| 2026-05-23 00:00 |
20:30:16.77 |
-28:00:28.8 |
HIP 101283 |
20.09 |
| 2026-05-23 12:00 |
20:30:17.24 |
-28:01:24.3 |
HIP 101283 |
19.82 |
| 2026-05-24 00:00 |
20:30:17.42 |
-28:02:20.6 |
HIP 101283 |
19.66 |
| 2026-05-24 12:00 |
20:30:17.29 |
-28:03:17.6 |
HIP 101283 |
19.61 |
| 2026-05-25 00:00 |
20:30:16.87 |
-28:04:15.5 |
HIP 101283 |
19.67 |
| 2026-05-25 12:00 |
20:30:16.15 |
-28:05:14.2 |
HIP 101283 |
19.85 |
| 2026-05-26 00:00 |
20:30:15.14 |
-28:06:13.7 |
HIP 101283 |
20.13 |
| 2026-05-26 12:00 |
20:30:13.82 |
-28:07:13.9 |
HIP 101283 |
20.54 |
| 2026-05-27 00:00 |
20:30:12.21 |
-28:08:14.9 |
HIP 101283 |
21.05 |
| 2026-05-27 12:00 |
20:30:10.30 |
-28:09:16.7 |
HIP 101283 |
21.67 |
| 2026-05-28 00:00 |
20:30:08.09 |
-28:10:19.2 |
HIP 101242 |
21.55 |
| 2026-05-28 12:00 |
20:30:05.58 |
-28:11:22.5 |
HIP 101242 |
21.22 |
| 2026-05-29 00:00 |
20:30:02.78 |
-28:12:26.5 |
HIP 101242 |
21.00 |
| 2026-05-29 12:00 |
20:29:59.68 |
-28:13:31.2 |
HIP 101242 |
20.89 |
| 2026-05-30 00:00 |
20:29:56.28 |
-28:14:36.6 |
HIP 101242 |
20.91 |
| 2026-05-30 12:00 |
20:29:52.58 |
-28:15:42.7 |
HIP 101242 |
21.07 |
| 2026-05-31 00:00 |
20:29:48.59 |
-28:16:49.5 |
HIP 101242 |
21.36 |
| 2026-05-31 12:00 |
20:29:44.30 |
-28:17:57.0 |
HIP 101242 |
21.80 |
| 2026-06-01 00:00 |
20:29:39.72 |
-28:19:05.1 |
HIP 101242 |
22.39 |
| 2026-06-01 12:00 |
20:29:34.84 |
-28:20:13.9 |
HIP 100935 |
22.40 |
| 2026-06-02 00:00 |
20:29:29.66 |
-28:21:23.3 |
HIP 100935 |
21.57 |