C/2023 A3 (Tsuchinshan-ATLAS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 A3 (Tsuchinshan-ATLAS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2024-09-27T17:46:46.623360Z |
| Orbit solution date (soln_date, UTC) | 2026-03-07T11:42:50Z |
| Obs used | 7258 |
| NEO | - |
| M1 | 8.900 |
| K1 | 5.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2023-01-09T21:31:51.081600Z |
| Discovery magnitude (MPC) | 18.70 R |
| Discovery observatory (MPC) | D29 · Purple Mountain Observatory, XuYi Station |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2024-05-17.0000000 |
| e | 1.00009553 |
| q (au) | 0.391430 |
| a (au) | -4097.517991 |
| i (deg) | 139.112133 |
| Ω (om, deg) | 21.559475 |
| ω (w, deg) | 308.491738 |
| M (ma, deg) | -0.000503 |
Magnitude
Scatter + Global Linear
$$ M_a = (8.258 + 4.231\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.258 |
| n | 4.231 |
| gf | 1.000 |
| gb | -0.828 |
| k | 0.894 |
| 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 |
|---|---|---|---|
| 2022-04-09 | 2024-02-07 | +5.2145 | -4.499 |
| 2024-02-07 | 2024-04-30 | -14.1699 | +6.847 |
| 2024-04-30 | 2024-09-27 | +1.3460 | -0.612 |
| 2024-09-27 | 2024-10-09 | -8.4200 | -3.439 |
| 2024-10-09 | 2024-10-26 | +11.0185 | +1.937 |
| 2024-10-26 | 2024-11-20 | -8.9706 | -0.073 |
| 2024-11-20 | 2025-11-20 | +4.7797 | -1.727 |
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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 18:56:29.90 | +16:43:22.1 | HIP 93033 | 8.70 |
| 2026-03-26 12:00 | 18:56:29.09 | +16:45:58.1 | HIP 93033 | 9.13 |
| 2026-03-27 00:00 | 18:56:28.12 | +16:48:34.2 | HIP 93033 | 10.26 |
| 2026-03-27 12:00 | 18:56:27.01 | +16:51:10.5 | HIP 93033 | 11.90 |
| 2026-03-28 00:00 | 18:56:25.74 | +16:53:46.8 | HIP 93033 | 13.87 |
| 2026-03-28 12:00 | 18:56:24.33 | +16:56:23.2 | HIP 93033 | 16.05 |
| 2026-03-29 00:00 | 18:56:22.76 | +16:58:59.6 | HIP 93033 | 18.37 |
| 2026-03-29 12:00 | 18:56:21.04 | +17:01:36.1 | HIP 92856 | 18.71 |
| 2026-03-30 00:00 | 18:56:19.18 | +17:04:12.7 | HIP 92856 | 16.99 |
| 2026-03-30 12:00 | 18:56:17.16 | +17:06:49.3 | HIP 92856 | 15.50 |
| 2026-03-31 00:00 | 18:56:14.99 | +17:09:25.9 | HIP 92856 | 14.32 |
| 2026-03-31 12:00 | 18:56:12.66 | +17:12:02.5 | HIP 92856 | 13.52 |
| 2026-04-01 00:00 | 18:56:10.19 | +17:14:39.1 | HIP 92856 | 13.19 |
| 2026-04-01 12:00 | 18:56:07.56 | +17:17:15.7 | HIP 92856 | 13.37 |
| 2026-04-02 00:00 | 18:56:04.78 | +17:19:52.3 | HIP 92856 | 14.03 |
| 2026-04-02 12:00 | 18:56:01.84 | +17:22:28.8 | HIP 92856 | 15.12 |
| 2026-04-03 00:00 | 18:55:58.76 | +17:25:05.3 | HIP 92856 | 16.56 |
| 2026-04-03 12:00 | 18:55:55.52 | +17:27:41.8 | HIP 92856 | 18.28 |
| 2026-04-04 00:00 | 18:55:52.12 | +17:30:18.1 | HIP 92856 | 20.19 |
| 2026-04-04 12:00 | 18:55:48.58 | +17:32:54.4 | HIP 92856 | 22.27 |
| 2026-04-05 00:00 | 18:55:44.87 | +17:35:30.6 | HIP 93060 | 23.89 |
| 2026-04-05 12:00 | 18:55:41.02 | +17:38:06.7 | HIP 92934 | 22.28 |
| 2026-04-06 00:00 | 18:55:37.01 | +17:40:42.7 | HIP 92934 | 20.05 |
| 2026-04-06 12:00 | 18:55:32.84 | +17:43:18.5 | HIP 92934 | 17.99 |
| 2026-04-07 00:00 | 18:55:28.52 | +17:45:54.3 | HIP 92934 | 16.17 |
| 2026-04-07 12:00 | 18:55:24.04 | +17:48:29.8 | HIP 92934 | 14.68 |
| 2026-04-08 00:00 | 18:55:19.41 | +17:51:05.2 | HIP 92934 | 13.64 |
| 2026-04-08 12:00 | 18:55:14.62 | +17:53:40.4 | HIP 92934 | 13.17 |
| 2026-04-09 00:00 | 18:55:09.68 | +17:56:15.4 | HIP 92934 | 13.33 |
| 2026-04-09 12:00 | 18:55:04.58 | +17:58:50.2 | HIP 92803 | 13.72 |
| 2026-04-10 00:00 | 18:54:59.33 | +18:01:24.8 | HIP 92803 | 10.88 |
| 2026-04-10 12:00 | 18:54:53.91 | +18:03:59.2 | HIP 92803 | 8.03 |
| 2026-04-11 00:00 | 18:54:48.35 | +18:06:33.3 | HIP 92803 | 5.19 |
| 2026-04-11 12:00 | 18:54:42.62 | +18:09:07.2 | HIP 92803 | 2.45 |
| 2026-04-12 00:00 | 18:54:36.74 | +18:11:40.8 | HIP 92803 | 1.36 |
| 2026-04-12 12:00 | 18:54:30.70 | +18:14:14.1 | HIP 92803 | 3.84 |
| 2026-04-13 00:00 | 18:54:24.51 | +18:16:47.1 | HIP 92803 | 6.70 |
| 2026-04-13 12:00 | 18:54:18.16 | +18:19:19.8 | HIP 92803 | 9.62 |
| 2026-04-14 00:00 | 18:54:11.65 | +18:21:52.1 | HIP 92803 | 12.57 |
| 2026-04-14 12:00 | 18:54:04.99 | +18:24:24.2 | HIP 92789 | 13.82 |
| 2026-04-15 00:00 | 18:53:58.16 | +18:26:55.8 | HIP 92789 | 12.48 |
| 2026-04-15 12:00 | 18:53:51.19 | +18:29:27.1 | HIP 92789 | 11.80 |
| 2026-04-16 00:00 | 18:53:44.05 | +18:31:58.1 | HIP 92789 | 11.90 |