| 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) |
| 2026-07-29 00:00 |
21:45:43.75 |
-64:56:26.6 |
HIP 107349 |
10.46 |
| 2026-07-29 12:00 |
21:45:20.34 |
-64:56:28.7 |
HIP 107349 |
8.79 |
| 2026-07-30 00:00 |
21:44:56.87 |
-64:56:29.6 |
HIP 107349 |
7.57 |
| 2026-07-30 12:00 |
21:44:33.35 |
-64:56:29.3 |
HIP 107349 |
7.08 |
| 2026-07-31 00:00 |
21:44:09.76 |
-64:56:27.8 |
HIP 107349 |
7.45 |
| 2026-07-31 12:00 |
21:43:46.13 |
-64:56:25.0 |
HIP 107349 |
8.59 |
| 2026-08-01 00:00 |
21:43:22.44 |
-64:56:21.0 |
HIP 107349 |
10.24 |
| 2026-08-01 12:00 |
21:42:58.71 |
-64:56:15.8 |
HIP 107349 |
12.20 |
| 2026-08-02 00:00 |
21:42:34.93 |
-64:56:09.3 |
HIP 107349 |
14.34 |
| 2026-08-02 12:00 |
21:42:11.11 |
-64:56:01.5 |
HIP 107349 |
16.61 |
| 2026-08-03 00:00 |
21:41:47.26 |
-64:55:52.5 |
HIP 107349 |
18.95 |
| 2026-08-03 12:00 |
21:41:23.36 |
-64:55:42.2 |
HIP 107349 |
21.35 |
| 2026-08-04 00:00 |
21:40:59.44 |
-64:55:30.7 |
HIP 106818 |
19.71 |
| 2026-08-04 12:00 |
21:40:35.48 |
-64:55:17.8 |
HIP 106818 |
17.23 |
| 2026-08-05 00:00 |
21:40:11.50 |
-64:55:03.7 |
HIP 106818 |
14.77 |
| 2026-08-05 12:00 |
21:39:47.49 |
-64:54:48.3 |
HIP 106818 |
12.34 |
| 2026-08-06 00:00 |
21:39:23.46 |
-64:54:31.6 |
HIP 106818 |
9.96 |
| 2026-08-06 12:00 |
21:38:59.42 |
-64:54:13.6 |
HIP 106818 |
7.68 |
| 2026-08-07 00:00 |
21:38:35.36 |
-64:53:54.3 |
HIP 106818 |
5.64 |
| 2026-08-07 12:00 |
21:38:11.28 |
-64:53:33.7 |
HIP 106818 |
4.21 |
| 2026-08-08 00:00 |
21:37:47.20 |
-64:53:11.7 |
HIP 106818 |
4.10 |
| 2026-08-08 12:00 |
21:37:23.11 |
-64:52:48.5 |
HIP 106818 |
5.39 |
| 2026-08-09 00:00 |
21:36:59.03 |
-64:52:23.9 |
HIP 106818 |
7.39 |
| 2026-08-09 12:00 |
21:36:34.94 |
-64:51:58.1 |
HIP 106588 |
9.33 |
| 2026-08-10 00:00 |
21:36:10.85 |
-64:51:30.8 |
HIP 106588 |
6.85 |
| 2026-08-10 12:00 |
21:35:46.78 |
-64:51:02.3 |
HIP 106588 |
4.47 |
| 2026-08-11 00:00 |
21:35:22.71 |
-64:50:32.4 |
HIP 106588 |
2.56 |
| 2026-08-11 12:00 |
21:34:58.65 |
-64:50:01.2 |
HIP 106588 |
2.58 |
| 2026-08-12 00:00 |
21:34:34.62 |
-64:49:28.7 |
HIP 106588 |
4.51 |
| 2026-08-12 12:00 |
21:34:10.60 |
-64:48:54.8 |
HIP 106588 |
6.90 |
| 2026-08-13 00:00 |
21:33:46.61 |
-64:48:19.6 |
HIP 106588 |
9.41 |
| 2026-08-13 12:00 |
21:33:22.64 |
-64:47:43.0 |
HIP 106588 |
11.97 |
| 2026-08-14 00:00 |
21:32:58.70 |
-64:47:05.1 |
HIP 106588 |
14.55 |
| 2026-08-14 12:00 |
21:32:34.80 |
-64:46:25.8 |
HIP 106588 |
17.14 |
| 2026-08-15 00:00 |
21:32:10.93 |
-64:45:45.2 |
HIP 106588 |
19.75 |
| 2026-08-15 12:00 |
21:31:47.10 |
-64:45:03.3 |
HIP 106588 |
22.36 |
| 2026-08-16 00:00 |
21:31:23.32 |
-64:44:20.0 |
HIP 106588 |
24.97 |
| 2026-08-16 12:00 |
21:30:59.58 |
-64:43:35.4 |
HIP 106588 |
27.60 |
| 2026-08-17 00:00 |
21:30:35.89 |
-64:42:49.4 |
HIP 106588 |
30.22 |
| 2026-08-17 12:00 |
21:30:12.25 |
-64:42:02.1 |
HIP 106588 |
32.85 |
| 2026-08-18 00:00 |
21:29:48.66 |
-64:41:13.5 |
HIP 106588 |
35.48 |
| 2026-08-18 12:00 |
21:29:25.13 |
-64:40:23.5 |
HIP 105664 |
34.58 |
| 2026-08-19 00:00 |
21:29:01.66 |
-64:39:32.2 |
HIP 105664 |
32.36 |