C/2024 A1 (ATLAS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2024 A1 (ATLAS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2025-06-13T17:19:57.138240Z |
| Orbit solution date (soln_date, UTC) | 2026-05-28T12:12:15Z |
| Obs used | 1934 |
| NEO | - |
| M1 | 11.200 |
| K1 | 4.750 |
| PC | - |
| Discovery observation (MPC, UTC) | 2024-01-03T04:58:49.900800Z |
| Discovery magnitude (MPC) | 18.80 o |
| Discovery observatory (MPC) | W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2025-04-26.0000000 |
| e | 1.00208860 |
| q (au) | 3.875284 |
| a (au) | -1855.447684 |
| i (deg) | 94.455606 |
| Ω (om, deg) | 112.137127 |
| ω (w, deg) | 353.313603 |
| M (ma, deg) | -0.000601 |
Magnitude
Scatter + Global Linear
$$ M_a = (9.259 + 2.484\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 9.259 |
| n | 2.484 |
| gf | 1.000 |
| gb | -0.626 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) | End (UTC) | a | b |
|---|---|---|---|
| 2024-01-03 | 2025-05-09 | +0.5728 | -0.580 |
| 2025-09-01 | 2026-05-25 | +3.9275 | -2.191 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Finding Chart
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-06-01 00:00 | 07:00:45.75 | +64:05:06.0 | HIP 33956 | 15.34 |
| 2026-06-01 12:00 | 07:01:24.75 | +64:05:58.2 | HIP 33956 | 12.59 |
| 2026-06-02 00:00 | 07:02:03.95 | +64:06:50.9 | HIP 33956 | 10.94 |
| 2026-06-02 12:00 | 07:02:43.34 | +64:07:44.3 | HIP 33956 | 10.94 |
| 2026-06-03 00:00 | 07:03:22.91 | +64:08:38.3 | HIP 33956 | 12.60 |
| 2026-06-03 12:00 | 07:04:02.68 | +64:09:32.8 | HIP 33956 | 15.41 |
| 2026-06-04 00:00 | 07:04:42.63 | +64:10:28.0 | HIP 33956 | 18.88 |
| 2026-06-04 12:00 | 07:05:22.77 | +64:11:23.7 | HIP 34294 | 15.85 |
| 2026-06-05 00:00 | 07:06:03.09 | +64:12:20.0 | HIP 34294 | 13.31 |
| 2026-06-05 12:00 | 07:06:43.60 | +64:13:16.9 | HIP 34294 | 11.97 |
| 2026-06-06 00:00 | 07:07:24.30 | +64:14:14.4 | HIP 34480 | 11.77 |
| 2026-06-06 12:00 | 07:08:05.18 | +64:15:12.4 | HIP 34480 | 8.15 |
| 2026-06-07 00:00 | 07:08:46.24 | +64:16:11.0 | HIP 34480 | 5.94 |
| 2026-06-07 12:00 | 07:09:27.48 | +64:17:10.2 | HIP 34480 | 6.77 |
| 2026-06-08 00:00 | 07:10:08.91 | +64:18:10.0 | HIP 34480 | 9.92 |
| 2026-06-08 12:00 | 07:10:50.52 | +64:19:10.4 | HIP 34480 | 13.91 |
| 2026-06-09 00:00 | 07:11:32.30 | +64:20:11.3 | HIP 34480 | 18.21 |
| 2026-06-09 12:00 | 07:12:14.27 | +64:21:12.8 | HIP 34480 | 22.66 |
| 2026-06-10 00:00 | 07:12:56.41 | +64:22:14.9 | HIP 34480 | 27.20 |
| 2026-06-10 12:00 | 07:13:38.74 | +64:23:17.5 | HIP 35161 | 28.13 |
| 2026-06-11 00:00 | 07:14:21.23 | +64:24:20.7 | HIP 35161 | 24.97 |
| 2026-06-11 12:00 | 07:15:03.91 | +64:25:24.5 | HIP 35161 | 22.34 |
| 2026-06-12 00:00 | 07:15:46.76 | +64:26:28.9 | HIP 35161 | 20.44 |
| 2026-06-12 12:00 | 07:16:29.79 | +64:27:33.8 | HIP 35161 | 19.53 |
| 2026-06-13 00:00 | 07:17:12.99 | +64:28:39.3 | HIP 35161 | 19.73 |
| 2026-06-13 12:00 | 07:17:56.36 | +64:29:45.4 | HIP 35161 | 21.04 |
| 2026-06-14 00:00 | 07:18:39.90 | +64:30:52.1 | HIP 35161 | 23.27 |
| 2026-06-14 12:00 | 07:19:23.62 | +64:31:59.3 | HIP 35466 | 25.05 |
| 2026-06-15 00:00 | 07:20:07.50 | +64:33:07.1 | HIP 35466 | 26.72 |
| 2026-06-15 12:00 | 07:20:51.56 | +64:34:15.5 | HIP 35466 | 29.14 |
| 2026-06-16 00:00 | 07:21:35.78 | +64:35:24.4 | HIP 35913 | 31.51 |
| 2026-06-16 12:00 | 07:22:20.17 | +64:36:33.9 | HIP 35913 | 30.26 |
| 2026-06-17 00:00 | 07:23:04.72 | +64:37:44.0 | HIP 35913 | 29.79 |
| 2026-06-17 12:00 | 07:23:49.44 | +64:38:54.7 | HIP 36149 | 25.98 |
| 2026-06-18 00:00 | 07:24:34.32 | +64:40:05.9 | HIP 36149 | 21.83 |
| 2026-06-18 12:00 | 07:25:19.37 | +64:41:17.7 | HIP 36149 | 18.06 |
| 2026-06-19 00:00 | 07:26:04.57 | +64:42:30.0 | HIP 36149 | 14.98 |
| 2026-06-19 12:00 | 07:26:49.94 | +64:43:43.0 | HIP 36149 | 13.10 |
| 2026-06-20 00:00 | 07:27:35.47 | +64:44:56.5 | HIP 36327 | 11.81 |
| 2026-06-20 12:00 | 07:28:21.16 | +64:46:10.5 | HIP 36327 | 10.95 |
| 2026-06-21 00:00 | 07:29:07.01 | +64:47:25.1 | HIP 36327 | 12.31 |
| 2026-06-21 12:00 | 07:29:53.01 | +64:48:40.3 | HIP 36327 | 15.32 |
| 2026-06-22 00:00 | 07:30:39.18 | +64:49:56.1 | HIP 36327 | 19.23 |