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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 18:44:06.31 | +20:28:03.7 | HIP 91770 | 22.16 |
| 2026-05-12 12:00 | 18:43:51.50 | +20:29:54.3 | HIP 91770 | 18.27 |
| 2026-05-13 00:00 | 18:43:36.57 | +20:31:43.7 | HIP 91770 | 14.38 |
| 2026-05-13 12:00 | 18:43:21.51 | +20:33:32.0 | HIP 91770 | 10.53 |
| 2026-05-14 00:00 | 18:43:06.33 | +20:35:19.1 | HIP 91770 | 6.79 |
| 2026-05-14 12:00 | 18:42:51.03 | +20:37:05.0 | HIP 91770 | 3.63 |
| 2026-05-15 00:00 | 18:42:35.60 | +20:38:49.8 | HIP 91770 | 3.51 |
| 2026-05-15 12:00 | 18:42:20.06 | +20:40:33.3 | HIP 91770 | 6.63 |
| 2026-05-16 00:00 | 18:42:04.39 | +20:42:15.7 | HIP 91770 | 10.42 |
| 2026-05-16 12:00 | 18:41:48.61 | +20:43:56.8 | HIP 91770 | 14.37 |
| 2026-05-17 00:00 | 18:41:32.71 | +20:45:36.7 | HIP 91770 | 18.38 |
| 2026-05-17 12:00 | 18:41:16.70 | +20:47:15.4 | HIP 91770 | 22.43 |
| 2026-05-18 00:00 | 18:41:00.58 | +20:48:52.7 | HIP 91547 | 20.71 |
| 2026-05-18 12:00 | 18:40:44.34 | +20:50:28.9 | HIP 91547 | 17.37 |
| 2026-05-19 00:00 | 18:40:27.99 | +20:52:03.7 | HIP 91547 | 14.45 |
| 2026-05-19 12:00 | 18:40:11.53 | +20:53:37.2 | HIP 91547 | 12.27 |
| 2026-05-20 00:00 | 18:39:54.97 | +20:55:09.4 | HIP 91468 | 8.40 |
| 2026-05-20 12:00 | 18:39:38.30 | +20:56:40.3 | HIP 91468 | 4.52 |
| 2026-05-21 00:00 | 18:39:21.52 | +20:58:09.9 | HIP 91468 | 2.25 |
| 2026-05-21 12:00 | 18:39:04.64 | +20:59:38.1 | HIP 91468 | 4.98 |
| 2026-05-22 00:00 | 18:38:47.66 | +21:01:05.0 | HIP 91468 | 8.95 |
| 2026-05-22 12:00 | 18:38:30.58 | +21:02:30.5 | HIP 91468 | 13.08 |
| 2026-05-23 00:00 | 18:38:13.40 | +21:03:54.7 | HIP 91468 | 17.27 |
| 2026-05-23 12:00 | 18:37:56.13 | +21:05:17.5 | HIP 91468 | 21.50 |
| 2026-05-24 00:00 | 18:37:38.76 | +21:06:38.9 | HIP 91252 | 17.87 |
| 2026-05-24 12:00 | 18:37:21.29 | +21:07:58.8 | HIP 91252 | 14.34 |
| 2026-05-25 00:00 | 18:37:03.73 | +21:09:17.4 | HIP 91252 | 11.36 |
| 2026-05-25 12:00 | 18:36:46.08 | +21:10:34.6 | HIP 91252 | 9.47 |
| 2026-05-26 00:00 | 18:36:28.35 | +21:11:50.3 | HIP 91252 | 9.39 |
| 2026-05-26 12:00 | 18:36:10.52 | +21:13:04.7 | HIP 91252 | 11.17 |
| 2026-05-27 00:00 | 18:35:52.61 | +21:14:17.5 | HIP 91140 | 11.04 |
| 2026-05-27 12:00 | 18:35:34.61 | +21:15:29.0 | HIP 91140 | 11.06 |
| 2026-05-28 00:00 | 18:35:16.53 | +21:16:39.0 | HIP 91140 | 12.66 |
| 2026-05-28 12:00 | 18:34:58.37 | +21:17:47.5 | HIP 91088 | 11.69 |
| 2026-05-29 00:00 | 18:34:40.13 | +21:18:54.5 | HIP 91088 | 10.39 |
| 2026-05-29 12:00 | 18:34:21.81 | +21:20:00.1 | HIP 91088 | 10.88 |
| 2026-05-30 00:00 | 18:34:03.41 | +21:21:04.1 | HIP 91088 | 12.98 |
| 2026-05-30 12:00 | 18:33:44.94 | +21:22:06.7 | HIP 91088 | 16.07 |
| 2026-05-31 00:00 | 18:33:26.40 | +21:23:07.8 | HIP 91088 | 19.70 |
| 2026-05-31 12:00 | 18:33:07.78 | +21:24:07.4 | HIP 91088 | 23.62 |
| 2026-06-01 00:00 | 18:32:49.10 | +21:25:05.5 | HIP 90961 | 27.33 |
| 2026-06-01 12:00 | 18:32:30.34 | +21:26:02.0 | HIP 90751 | 25.04 |
| 2026-06-02 00:00 | 18:32:11.52 | +21:26:57.0 | HIP 90751 | 20.90 |