C/2025 L1 (ATLAS)
| Parameter |
Value |
| Designation |
C/2025 L1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-01-12T17:58:32.070720Z |
| Orbit solution date (soln_date, UTC) |
2026-01-07T15:42:42Z |
| Obs used |
71 |
| NEO |
- |
| M1 |
12.200 |
| K1 |
7.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-06-06T09:16:16.579200Z |
| Discovery magnitude (MPC) |
18.22 c |
| Discovery observatory (MPC) |
W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-06-21.0000000 |
| e |
1.00135270 |
| q (au) |
1.679515 |
| a (au) |
-1241.602022 |
| i (deg) |
114.137000 |
| Ω (om, deg) |
208.105583 |
| ω (w, deg) |
341.257615 |
| M (ma, deg) |
-0.004635 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.150 + 3.365\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.150 |
| n |
3.365 |
| gf |
1.000 |
| gb |
-0.644 |
| k |
0.800 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
16:01:41.33 |
-25:23:55.5 |
HIP 78494 |
12.47 |
| 2026-02-03 12:00 |
16:01:44.14 |
-25:08:50.4 |
HIP 78494 |
5.01 |
| 2026-02-04 00:00 |
16:01:46.49 |
-24:53:34.3 |
HIP 78602 |
16.53 |
| 2026-02-04 12:00 |
16:01:48.35 |
-24:38:07.0 |
HIP 78510 |
18.69 |
| 2026-02-05 00:00 |
16:01:49.72 |
-24:22:28.3 |
HIP 78510 |
3.62 |
| 2026-02-05 12:00 |
16:01:50.59 |
-24:06:38.0 |
HIP 78482 |
9.15 |
| 2026-02-06 00:00 |
16:01:50.96 |
-23:50:35.9 |
HIP 78482 |
13.48 |
| 2026-02-06 12:00 |
16:01:50.83 |
-23:34:21.7 |
HIP 78586 |
26.63 |
| 2026-02-07 00:00 |
16:01:50.17 |
-23:17:55.2 |
HIP 78586 |
14.53 |
| 2026-02-07 12:00 |
16:01:49.00 |
-23:01:16.2 |
HIP 78586 |
16.15 |
| 2026-02-08 00:00 |
16:01:47.29 |
-22:44:24.4 |
HIP 78549 |
6.83 |
| 2026-02-08 12:00 |
16:01:45.04 |
-22:27:19.7 |
HIP 78549 |
15.40 |
| 2026-02-09 00:00 |
16:01:42.25 |
-22:10:01.7 |
HIP 78472 |
7.90 |
| 2026-02-09 12:00 |
16:01:38.90 |
-21:52:30.2 |
HIP 78530 |
7.39 |
| 2026-02-10 00:00 |
16:01:34.99 |
-21:34:45.1 |
HIP 78530 |
24.53 |
| 2026-02-10 12:00 |
16:01:30.51 |
-21:16:45.9 |
HIP 78467 |
9.39 |
| 2026-02-11 00:00 |
16:01:25.45 |
-20:58:32.6 |
HIP 78467 |
11.72 |
| 2026-02-11 12:00 |
16:01:19.81 |
-20:40:04.8 |
HIP 78543 |
11.96 |
| 2026-02-12 00:00 |
16:01:13.57 |
-20:21:22.2 |
HIP 78420 |
10.69 |
| 2026-02-12 12:00 |
16:01:06.73 |
-20:02:24.7 |
HIP 78420 |
25.75 |
| 2026-02-13 00:00 |
16:00:59.28 |
-19:43:11.9 |
HIP 78551 |
24.03 |
| 2026-02-13 12:00 |
16:00:51.20 |
-19:23:43.6 |
HIP 78462 |
6.72 |
| 2026-02-14 00:00 |
16:00:42.50 |
-19:03:59.5 |
HIP 78454 |
7.34 |
| 2026-02-14 12:00 |
16:00:33.15 |
-18:43:59.4 |
HIP 78454 |
15.12 |
| 2026-02-15 00:00 |
16:00:23.16 |
-18:23:42.9 |
HIP 78314 |
15.96 |
| 2026-02-15 12:00 |
16:00:12.51 |
-18:03:09.9 |
HIP 78314 |
16.24 |
| 2026-02-16 00:00 |
16:00:01.19 |
-17:42:20.0 |
HIP 78426 |
9.11 |
| 2026-02-16 12:00 |
15:59:49.19 |
-17:21:13.0 |
HIP 78216 |
21.32 |
| 2026-02-17 00:00 |
15:59:36.51 |
-16:59:48.6 |
HIP 78193 |
24.24 |
| 2026-02-17 12:00 |
15:59:23.13 |
-16:38:06.6 |
HIP 78400 |
14.95 |
| 2026-02-18 00:00 |
15:59:09.05 |
-16:16:06.6 |
HIP 78295 |
3.02 |
| 2026-02-18 12:00 |
15:58:54.25 |
-15:53:48.4 |
HIP 78295 |
20.05 |
| 2026-02-19 00:00 |
15:58:38.72 |
-15:31:11.7 |
HIP 78211 |
6.22 |
| 2026-02-19 12:00 |
15:58:22.46 |
-15:08:16.3 |
HIP 78239 |
6.51 |
| 2026-02-20 00:00 |
15:58:05.45 |
-14:45:01.9 |
HIP 78204 |
17.46 |
| 2026-02-20 12:00 |
15:57:47.68 |
-14:21:28.3 |
HIP 78207 |
7.43 |
| 2026-02-21 00:00 |
15:57:29.14 |
-13:57:35.1 |
HIP 78065 |
16.85 |
| 2026-02-21 12:00 |
15:57:09.83 |
-13:33:22.2 |
HIP 78096 |
6.03 |
| 2026-02-22 00:00 |
15:56:49.72 |
-13:08:49.3 |
HIP 78107 |
10.75 |
| 2026-02-22 12:00 |
15:56:28.82 |
-12:43:56.1 |
HIP 78084 |
11.71 |
| 2026-02-23 00:00 |
15:56:07.11 |
-12:18:42.5 |
HIP 77863 |
33.95 |
| 2026-02-23 12:00 |
15:55:44.58 |
-11:53:08.1 |
HIP 77863 |
29.49 |
| 2026-02-24 00:00 |
15:55:21.22 |
-11:27:12.8 |
HIP 77878 |
27.37 |