C/2023 C2 (ATLAS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 C2 (ATLAS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2024-11-16T18:42:57.139200Z |
| Orbit solution date (soln_date, UTC) | 2026-04-14T13:42:19Z |
| Obs used | 1938 |
| NEO | - |
| M1 | 10.900 |
| K1 | 4.500 |
| PC | 0.030 |
| Discovery observation (MPC, UTC) | 2023-02-01T06:05:54.758400Z |
| Discovery magnitude (MPC) | 19.12 o |
| Discovery observatory (MPC) | W68 · ATLAS Chile, Rio Hurtado |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2025-03-15.0000000 |
| e | 0.99899713 |
| q (au) | 2.368469 |
| a (au) | 2361.685725 |
| i (deg) | 48.322065 |
| Ω (om, deg) | 301.004734 |
| ω (w, deg) | 357.444180 |
| M (ma, deg) | 0.001015 |
Magnitude
Scatter + Global Linear
$$ M_a = (10.024 + 2.746\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 10.024 |
| n | 2.746 |
| gf | 1.000 |
| gb | -0.700 |
| k | 0.961 |
| 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 |
|---|---|---|---|
| 2023-02-01 | 2024-02-08 | +0.7165 | -0.130 |
| 2024-02-08 | 2024-04-08 | +3.3968 | -1.581 |
| 2024-04-08 | 2024-11-13 | +2.8603 | -1.491 |
| 2024-11-28 | 2025-10-02 | -0.7416 | +0.401 |
| 2025-10-02 | 2026-04-12 | -7.8353 | +4.907 |
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 | 01:55:39.07 | +56:47:34.8 | HIP 8929 | 13.93 |
| 2026-06-01 12:00 | 01:56:12.31 | +56:50:51.9 | HIP 9048 | 9.14 |
| 2026-06-02 00:00 | 01:56:45.48 | +56:54:09.1 | HIP 9048 | 5.59 |
| 2026-06-02 12:00 | 01:57:18.56 | +56:57:26.5 | HIP 9048 | 6.43 |
| 2026-06-03 00:00 | 01:57:51.56 | +57:00:44.1 | HIP 9048 | 10.65 |
| 2026-06-03 12:00 | 01:58:24.47 | +57:04:01.9 | HIP 9048 | 15.71 |
| 2026-06-04 00:00 | 01:58:57.30 | +57:07:19.8 | HIP 9048 | 21.01 |
| 2026-06-04 12:00 | 01:59:30.04 | +57:10:38.0 | HIP 9048 | 26.39 |
| 2026-06-05 00:00 | 02:00:02.70 | +57:13:56.3 | HIP 9556 | 22.63 |
| 2026-06-05 12:00 | 02:00:35.27 | +57:17:14.8 | HIP 9556 | 17.78 |
| 2026-06-06 00:00 | 02:01:07.75 | +57:20:33.5 | HIP 9556 | 13.47 |
| 2026-06-06 12:00 | 02:01:40.14 | +57:23:52.4 | HIP 9556 | 10.38 |
| 2026-06-07 00:00 | 02:02:12.44 | +57:27:11.4 | HIP 9556 | 9.73 |
| 2026-06-07 12:00 | 02:02:44.64 | +57:30:30.6 | HIP 9556 | 11.90 |
| 2026-06-08 00:00 | 02:03:16.76 | +57:33:50.0 | HIP 9556 | 15.75 |
| 2026-06-08 12:00 | 02:03:48.78 | +57:37:09.6 | HIP 9556 | 20.35 |
| 2026-06-09 00:00 | 02:04:20.70 | +57:40:29.3 | HIP 9556 | 25.27 |
| 2026-06-09 12:00 | 02:04:52.53 | +57:43:49.2 | HIP 9936 | 24.21 |
| 2026-06-10 00:00 | 02:05:24.27 | +57:47:09.2 | HIP 9936 | 20.41 |
| 2026-06-10 12:00 | 02:05:55.90 | +57:50:29.4 | HIP 9936 | 17.50 |
| 2026-06-11 00:00 | 02:06:27.44 | +57:53:49.7 | HIP 9857 | 14.68 |
| 2026-06-11 12:00 | 02:06:58.87 | +57:57:10.2 | HIP 9857 | 11.15 |
| 2026-06-12 00:00 | 02:07:30.20 | +58:00:30.9 | HIP 9857 | 9.47 |
| 2026-06-12 12:00 | 02:08:01.43 | +58:03:51.7 | HIP 9857 | 10.55 |
| 2026-06-13 00:00 | 02:08:32.56 | +58:07:12.6 | HIP 10024 | 11.95 |
| 2026-06-13 12:00 | 02:09:03.58 | +58:10:33.7 | HIP 10024 | 14.63 |
| 2026-06-14 00:00 | 02:09:34.49 | +58:13:54.9 | HIP 9990 | 13.50 |
| 2026-06-14 12:00 | 02:10:05.30 | +58:17:16.3 | HIP 9990 | 13.78 |
| 2026-06-15 00:00 | 02:10:36.00 | +58:20:37.7 | HIP 9990 | 15.87 |
| 2026-06-15 12:00 | 02:11:06.58 | +58:23:59.3 | HIP 9990 | 19.17 |
| 2026-06-16 00:00 | 02:11:37.06 | +58:27:21.1 | HIP 10379 | 17.44 |
| 2026-06-16 12:00 | 02:12:07.42 | +58:30:42.9 | HIP 10379 | 12.63 |
| 2026-06-17 00:00 | 02:12:37.67 | +58:34:04.9 | HIP 10379 | 8.35 |
| 2026-06-17 12:00 | 02:13:07.80 | +58:37:26.9 | HIP 10379 | 5.83 |
| 2026-06-18 00:00 | 02:13:37.82 | +58:40:49.1 | HIP 10379 | 7.20 |
| 2026-06-18 12:00 | 02:14:07.71 | +58:44:11.3 | HIP 10331 | 8.76 |
| 2026-06-19 00:00 | 02:14:37.49 | +58:47:33.7 | HIP 10331 | 11.76 |
| 2026-06-19 12:00 | 02:15:07.15 | +58:50:56.1 | HIP 10331 | 15.86 |
| 2026-06-20 00:00 | 02:15:36.69 | +58:54:18.7 | HIP 10653 | 19.37 |
| 2026-06-20 12:00 | 02:16:06.11 | +58:57:41.3 | HIP 10653 | 20.38 |
| 2026-06-21 00:00 | 02:16:35.40 | +59:01:04.0 | HIP 10829 | 21.71 |
| 2026-06-21 12:00 | 02:17:04.57 | +59:04:26.8 | HIP 10829 | 18.92 |
| 2026-06-22 00:00 | 02:17:33.61 | +59:07:49.7 | HIP 10829 | 17.23 |