C/2023 A3 (Tsuchinshan-ATLAS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2023 A3 (Tsuchinshan-ATLAS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2024-09-27T17:46:46.701120Z |
| Orbit solution date (soln_date, UTC) | 2025-12-18T15:12:22Z |
| Obs used | 7255 |
| 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 | 1.00009554 |
| q (au) | 0.391430 |
| a (au) | -4097.060010 |
| i (deg) | 139.112133 |
| Ω (om, deg) | 21.559475 |
| ω (w, deg) | 308.491736 |
| M (ma, deg) | -0.000503 |
Magnitude
Scatter + Global Linear
$$ M_a = (8.285 + 4.179\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 8.285 |
| n | 4.179 |
| gf | 1.000 |
| gb | -0.822 |
| k | 0.890 |
| 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 | 2024-02-08 | +5.1496 | -4.412 |
| 2024-02-08 | 2024-04-30 | -13.9802 | +6.778 |
| 2024-04-30 | 2024-09-27 | +1.4520 | -0.610 |
| 2024-09-27 | 2024-10-10 | -8.4368 | -3.517 |
| 2024-10-10 | 2024-10-26 | +11.4540 | +1.979 |
| 2024-10-26 | 2024-11-20 | -8.8074 | -0.072 |
| 2024-11-20 | 2025-11-20 | +4.8322 | -1.706 |
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) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 18:46:25.38 | +12:57:25.0 | HIP 92146 | 24.88 |
| 2026-02-03 12:00 | 18:46:36.76 | +12:59:01.6 | HIP 92146 | 25.96 |
| 2026-02-04 00:00 | 18:46:48.05 | +13:00:39.1 | HIP 92146 | 27.39 |
| 2026-02-04 12:00 | 18:46:59.27 | +13:02:17.6 | HIP 92222 | 26.36 |
| 2026-02-05 00:00 | 18:47:10.40 | +13:03:56.9 | HIP 92222 | 23.85 |
| 2026-02-05 12:00 | 18:47:21.44 | +13:05:37.2 | HIP 92222 | 21.50 |
| 2026-02-06 00:00 | 18:47:32.40 | +13:07:18.4 | HIP 92222 | 19.37 |
| 2026-02-06 12:00 | 18:47:43.28 | +13:09:00.5 | HIP 92222 | 17.54 |
| 2026-02-07 00:00 | 18:47:54.06 | +13:10:43.5 | HIP 92222 | 16.10 |
| 2026-02-07 12:00 | 18:48:04.76 | +13:12:27.5 | HIP 92222 | 15.15 |
| 2026-02-08 00:00 | 18:48:15.37 | +13:14:12.3 | HIP 92222 | 14.80 |
| 2026-02-08 12:00 | 18:48:25.89 | +13:15:57.9 | HIP 92222 | 15.07 |
| 2026-02-09 00:00 | 18:48:36.32 | +13:17:44.5 | HIP 92388 | 15.80 |
| 2026-02-09 12:00 | 18:48:46.66 | +13:19:32.0 | HIP 92388 | 14.13 |
| 2026-02-10 00:00 | 18:48:56.90 | +13:21:20.3 | HIP 92388 | 13.01 |
| 2026-02-10 12:00 | 18:49:07.05 | +13:23:09.5 | HIP 92388 | 12.59 |
| 2026-02-11 00:00 | 18:49:17.11 | +13:24:59.6 | HIP 92388 | 12.93 |
| 2026-02-11 12:00 | 18:49:27.08 | +13:26:50.5 | HIP 92388 | 13.97 |
| 2026-02-12 00:00 | 18:49:36.95 | +13:28:42.2 | HIP 92388 | 15.56 |
| 2026-02-12 12:00 | 18:49:46.72 | +13:30:34.8 | HIP 92388 | 17.55 |
| 2026-02-13 00:00 | 18:49:56.39 | +13:32:28.3 | HIP 92388 | 19.81 |
| 2026-02-13 12:00 | 18:50:05.97 | +13:34:22.6 | HIP 92428 | 20.92 |
| 2026-02-14 00:00 | 18:50:15.45 | +13:36:17.7 | HIP 92428 | 18.99 |
| 2026-02-14 12:00 | 18:50:24.83 | +13:38:13.6 | HIP 92428 | 17.35 |
| 2026-02-15 00:00 | 18:50:34.11 | +13:40:10.4 | HIP 92428 | 16.08 |
| 2026-02-15 12:00 | 18:50:43.28 | +13:42:07.9 | HIP 92428 | 15.27 |
| 2026-02-16 00:00 | 18:50:52.36 | +13:44:06.3 | HIP 92428 | 14.98 |
| 2026-02-16 12:00 | 18:51:01.33 | +13:46:05.4 | HIP 92428 | 15.25 |
| 2026-02-17 00:00 | 18:51:10.20 | +13:48:05.4 | HIP 92593 | 15.96 |
| 2026-02-17 12:00 | 18:51:18.96 | +13:50:06.1 | HIP 92593 | 13.04 |
| 2026-02-18 00:00 | 18:51:27.62 | +13:52:07.6 | HIP 92593 | 10.15 |
| 2026-02-18 12:00 | 18:51:36.17 | +13:54:09.8 | HIP 92593 | 7.30 |
| 2026-02-19 00:00 | 18:51:44.61 | +13:56:12.9 | HIP 92593 | 4.54 |
| 2026-02-19 12:00 | 18:51:52.95 | +13:58:16.6 | HIP 92593 | 2.20 |
| 2026-02-20 00:00 | 18:52:01.18 | +14:00:21.2 | HIP 92593 | 2.42 |
| 2026-02-20 12:00 | 18:52:09.29 | +14:02:26.4 | HIP 92593 | 4.84 |
| 2026-02-21 00:00 | 18:52:17.30 | +14:04:32.4 | HIP 92593 | 7.58 |
| 2026-02-21 12:00 | 18:52:25.20 | +14:06:39.1 | HIP 92593 | 10.38 |
| 2026-02-22 00:00 | 18:52:32.98 | +14:08:46.5 | HIP 92593 | 13.20 |
| 2026-02-22 12:00 | 18:52:40.66 | +14:10:54.6 | HIP 92725 | 14.86 |
| 2026-02-23 00:00 | 18:52:48.22 | +14:13:03.5 | HIP 92725 | 12.99 |
| 2026-02-23 12:00 | 18:52:55.66 | +14:15:13.0 | HIP 92725 | 11.54 |
| 2026-02-24 00:00 | 18:53:02.99 | +14:17:23.2 | HIP 92725 | 10.69 |