C/2026 C1 (Tsuchinshan)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2026 C1 (Tsuchinshan) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2028-11-06T23:43:38.496000Z |
| Orbit solution date (soln_date, UTC) | 2026-08-07T12:42:15Z |
| Obs used | 925 |
| NEO | - |
| M1 | 6.200 |
| K1 | 7.750 |
| PC | - |
| Discovery observation (MPC, UTC) | 2026-02-11T19:49:29.596800Z |
| Discovery magnitude (MPC) | 19.30 R |
| Discovery observatory (MPC) | D29 · Purple Mountain Observatory, XuYi Station |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2026-04-07.0000000 |
| e | 0.99990822 |
| q (au) | 1.152471 |
| a (au) | 12556.292501 |
| i (deg) | 99.595389 |
| Ω (om, deg) | 3.618968 |
| ω (w, deg) | 310.719114 |
| M (ma, deg) | 359.999338 |
Magnitude
Scatter + Global Linear
$$ M_a = (-1.647 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | -1.647 |
| n | 6.000 |
| gf | 0.834 |
| gb | -0.989 |
| k | 1.000 |
| δ90 | 5.767 |
| 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 |
|---|---|---|---|
| 2025-12-22 | 2026-08-22 | +36.8274 | -36.131 |
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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 12:21:23.62 | +03:02:01.4 | HIP 60264 | 18.33 |
| 2026-09-20 12:00 | 12:21:33.78 | +03:00:15.3 | HIP 60264 | 16.72 |
| 2026-09-21 00:00 | 12:21:43.96 | +02:58:29.2 | HIP 60264 | 15.56 |
| 2026-09-21 12:00 | 12:21:54.16 | +02:56:43.1 | HIP 60264 | 14.97 |
| 2026-09-22 00:00 | 12:22:04.38 | +02:54:57.0 | HIP 60264 | 15.01 |
| 2026-09-22 12:00 | 12:22:14.61 | +02:53:10.9 | HIP 60264 | 15.68 |
| 2026-09-23 00:00 | 12:22:24.87 | +02:51:24.7 | HIP 60264 | 16.91 |
| 2026-09-23 12:00 | 12:22:35.14 | +02:49:38.6 | HIP 60264 | 18.59 |
| 2026-09-24 00:00 | 12:22:45.43 | +02:47:52.4 | HIP 60264 | 20.61 |
| 2026-09-24 12:00 | 12:22:55.74 | +02:46:06.3 | HIP 60264 | 22.89 |
| 2026-09-25 00:00 | 12:23:06.06 | +02:44:20.1 | HIP 60264 | 25.35 |
| 2026-09-25 12:00 | 12:23:16.40 | +02:42:34.0 | HIP 60492 | 27.48 |
| 2026-09-26 00:00 | 12:23:26.76 | +02:40:47.9 | HIP 60492 | 24.81 |
| 2026-09-26 12:00 | 12:23:37.13 | +02:39:01.7 | HIP 60492 | 22.25 |
| 2026-09-27 00:00 | 12:23:47.51 | +02:37:15.6 | HIP 60492 | 19.86 |
| 2026-09-27 12:00 | 12:23:57.91 | +02:35:29.6 | HIP 60492 | 17.70 |
| 2026-09-28 00:00 | 12:24:08.32 | +02:33:43.5 | HIP 60492 | 15.88 |
| 2026-09-28 12:00 | 12:24:18.74 | +02:31:57.5 | HIP 60492 | 14.51 |
| 2026-09-29 00:00 | 12:24:29.17 | +02:30:11.5 | HIP 60492 | 13.75 |
| 2026-09-29 12:00 | 12:24:39.62 | +02:28:25.5 | HIP 60492 | 13.69 |
| 2026-09-30 00:00 | 12:24:50.07 | +02:26:39.5 | HIP 60492 | 14.34 |
| 2026-09-30 12:00 | 12:25:00.54 | +02:24:53.6 | HIP 60492 | 15.61 |
| 2026-10-01 00:00 | 12:25:11.01 | +02:23:07.7 | HIP 60492 | 17.37 |
| 2026-10-01 12:00 | 12:25:21.50 | +02:21:21.9 | HIP 60713 | 18.66 |
| 2026-10-02 00:00 | 12:25:31.99 | +02:19:36.1 | HIP 60713 | 16.81 |
| 2026-10-02 12:00 | 12:25:42.49 | +02:17:50.4 | HIP 60713 | 15.38 |
| 2026-10-03 00:00 | 12:25:53.00 | +02:16:04.7 | HIP 60667 | 13.70 |
| 2026-10-03 12:00 | 12:26:03.51 | +02:14:19.1 | HIP 60667 | 11.82 |
| 2026-10-04 00:00 | 12:26:14.03 | +02:12:33.5 | HIP 60667 | 10.56 |
| 2026-10-04 12:00 | 12:26:24.56 | +02:10:48.0 | HIP 60667 | 10.18 |
| 2026-10-05 00:00 | 12:26:35.09 | +02:09:02.5 | HIP 60667 | 10.75 |
| 2026-10-05 12:00 | 12:26:45.63 | +02:07:17.2 | HIP 60667 | 12.16 |
| 2026-10-06 00:00 | 12:26:56.17 | +02:05:31.9 | HIP 60667 | 14.14 |
| 2026-10-06 12:00 | 12:27:06.71 | +02:03:46.6 | HIP 60667 | 16.50 |
| 2026-10-07 00:00 | 12:27:17.25 | +02:02:01.5 | HIP 60667 | 19.09 |
| 2026-10-07 12:00 | 12:27:27.80 | +02:00:16.4 | HIP 60667 | 21.83 |
| 2026-10-08 00:00 | 12:27:38.34 | +01:58:31.5 | HIP 60936 | 22.55 |
| 2026-10-08 12:00 | 12:27:48.89 | +01:56:46.6 | HIP 60936 | 20.46 |
| 2026-10-09 00:00 | 12:27:59.44 | +01:55:01.8 | HIP 60936 | 18.66 |
| 2026-10-09 12:00 | 12:28:09.98 | +01:53:17.1 | HIP 60936 | 17.26 |
| 2026-10-10 00:00 | 12:28:20.52 | +01:51:32.6 | HIP 60936 | 16.36 |
| 2026-10-10 12:00 | 12:28:31.06 | +01:49:48.1 | HIP 60936 | 16.04 |
| 2026-10-11 00:00 | 12:28:41.60 | +01:48:03.7 | HIP 60936 | 16.33 |