| Parameter |
Value |
| Designation |
C/2025 Q1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2024-07-12T01:27:00.011520Z |
| Orbit solution date (soln_date, UTC) |
2025-12-12T11:12:31Z |
| Obs used |
24 |
| NEO |
- |
| M1 |
6.600 |
| K1 |
8.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-08-27T05:43:50.505600Z |
| Discovery magnitude (MPC) |
19.88 o |
| Discovery observatory (MPC) |
W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-01-29.0000000 |
| e |
0.99127748 |
| q (au) |
10.099968 |
| a (au) |
1157.918555 |
| i (deg) |
66.152955 |
| Ω (om, deg) |
326.964441 |
| ω (w, deg) |
280.236072 |
| M (ma, deg) |
0.005026 |
Magnitude
Scatter + Global Linear
$$
M_a = (-1.316 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
-1.316 |
| n |
6.000 |
| gf |
0.918 |
| gb |
-0.998 |
| k |
1.000 |
| δ90 |
9.569 |
| 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) |
| 2026-09-20 00:00 |
21:07:57.59 |
-63:01:55.0 |
HIP 104323 |
5.15 |
| 2026-09-20 12:00 |
21:07:42.97 |
-62:59:48.0 |
HIP 104323 |
3.63 |
| 2026-09-21 00:00 |
21:07:28.54 |
-62:57:40.1 |
HIP 104323 |
3.76 |
| 2026-09-21 12:00 |
21:07:14.30 |
-62:55:31.3 |
HIP 104323 |
5.42 |
| 2026-09-22 00:00 |
21:07:00.25 |
-62:53:21.7 |
HIP 104323 |
7.67 |
| 2026-09-22 12:00 |
21:06:46.40 |
-62:51:11.2 |
HIP 104323 |
10.13 |
| 2026-09-23 00:00 |
21:06:32.73 |
-62:48:59.8 |
HIP 104323 |
12.68 |
| 2026-09-23 12:00 |
21:06:19.26 |
-62:46:47.6 |
HIP 104323 |
15.27 |
| 2026-09-24 00:00 |
21:06:05.97 |
-62:44:34.6 |
HIP 104323 |
17.89 |
| 2026-09-24 12:00 |
21:05:52.89 |
-62:42:20.7 |
HIP 104323 |
20.52 |
| 2026-09-25 00:00 |
21:05:39.99 |
-62:40:06.0 |
HIP 104323 |
23.16 |
| 2026-09-25 12:00 |
21:05:27.29 |
-62:37:50.5 |
HIP 104323 |
25.80 |
| 2026-09-26 00:00 |
21:05:14.79 |
-62:35:34.2 |
HIP 103965 |
26.74 |
| 2026-09-26 12:00 |
21:05:02.47 |
-62:33:17.1 |
HIP 103965 |
24.11 |
| 2026-09-27 00:00 |
21:04:50.36 |
-62:30:59.2 |
HIP 103965 |
21.48 |
| 2026-09-27 12:00 |
21:04:38.44 |
-62:28:40.6 |
HIP 103965 |
18.86 |
| 2026-09-28 00:00 |
21:04:26.71 |
-62:26:21.2 |
HIP 103965 |
16.26 |
| 2026-09-28 12:00 |
21:04:15.18 |
-62:24:01.1 |
HIP 103965 |
13.69 |
| 2026-09-29 00:00 |
21:04:03.85 |
-62:21:40.2 |
HIP 103965 |
11.17 |
| 2026-09-29 12:00 |
21:03:52.71 |
-62:19:18.6 |
HIP 103965 |
8.73 |
| 2026-09-30 00:00 |
21:03:41.77 |
-62:16:56.3 |
HIP 103965 |
6.48 |
| 2026-09-30 12:00 |
21:03:31.03 |
-62:14:33.3 |
HIP 103965 |
4.71 |
| 2026-10-01 00:00 |
21:03:20.48 |
-62:12:09.5 |
HIP 103965 |
4.07 |
| 2026-10-01 12:00 |
21:03:10.14 |
-62:09:45.1 |
HIP 103965 |
5.03 |
| 2026-10-02 00:00 |
21:02:59.99 |
-62:07:20.0 |
HIP 103965 |
6.96 |
| 2026-10-02 12:00 |
21:02:50.03 |
-62:04:54.2 |
HIP 103965 |
9.26 |
| 2026-10-03 00:00 |
21:02:40.28 |
-62:02:27.8 |
HIP 103854 |
9.64 |
| 2026-10-03 12:00 |
21:02:30.72 |
-62:00:00.7 |
HIP 103854 |
7.26 |
| 2026-10-04 00:00 |
21:02:21.37 |
-61:57:32.9 |
HIP 103854 |
5.16 |
| 2026-10-04 12:00 |
21:02:12.21 |
-61:55:04.6 |
HIP 103854 |
3.88 |
| 2026-10-05 00:00 |
21:02:03.25 |
-61:52:35.6 |
HIP 103854 |
4.22 |
| 2026-10-05 12:00 |
21:01:54.48 |
-61:50:05.9 |
HIP 103854 |
5.91 |
| 2026-10-06 00:00 |
21:01:45.92 |
-61:47:35.7 |
HIP 103854 |
8.15 |
| 2026-10-06 12:00 |
21:01:37.56 |
-61:45:04.9 |
HIP 103854 |
10.61 |
| 2026-10-07 00:00 |
21:01:29.39 |
-61:42:33.5 |
HIP 103854 |
13.15 |
| 2026-10-07 12:00 |
21:01:21.43 |
-61:40:01.5 |
HIP 103854 |
15.74 |
| 2026-10-08 00:00 |
21:01:13.66 |
-61:37:29.0 |
HIP 103854 |
18.36 |
| 2026-10-08 12:00 |
21:01:06.09 |
-61:34:55.8 |
HIP 103854 |
21.00 |
| 2026-10-09 00:00 |
21:00:58.72 |
-61:32:22.2 |
HIP 103499 |
20.64 |
| 2026-10-09 12:00 |
21:00:51.55 |
-61:29:48.0 |
HIP 103499 |
20.50 |
| 2026-10-10 00:00 |
21:00:44.58 |
-61:27:13.3 |
HIP 103499 |
20.75 |
| 2026-10-10 12:00 |
21:00:37.80 |
-61:24:38.0 |
HIP 103499 |
21.36 |
| 2026-10-11 00:00 |
21:00:31.22 |
-61:22:02.3 |
HIP 103499 |
22.31 |