| Parameter |
Value |
| Designation |
C/2025 A3 (Tsuchinshan) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-03-15T00:48:41.667840Z |
| Orbit solution date (soln_date, UTC) |
2026-04-27T13:42:21Z |
| Obs used |
101 |
| NEO |
- |
| M1 |
13.500 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-01-05T19:43:38.208000Z |
| Discovery magnitude (MPC) |
19.60 R |
| Discovery observatory (MPC) |
D29 · Purple Mountain Observatory, XuYi Station |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-04-12.0000000 |
| e |
0.43162591 |
| q (au) |
5.792455 |
| a (au) |
10.191273 |
| i (deg) |
9.977406 |
| Ω (om, deg) |
322.434258 |
| ω (w, deg) |
222.303442 |
| M (ma, deg) |
349.789784 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.151 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.151 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.604 |
| k |
1.000 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
11:52:17.05 |
-08:01:21.3 |
HIP 57806 |
16.47 |
| 2026-06-01 12:00 |
11:52:20.16 |
-08:01:19.4 |
HIP 57806 |
17.23 |
| 2026-06-02 00:00 |
11:52:23.42 |
-08:01:18.5 |
HIP 57806 |
18.04 |
| 2026-06-02 12:00 |
11:52:26.83 |
-08:01:18.4 |
HIP 57806 |
18.88 |
| 2026-06-03 00:00 |
11:52:30.39 |
-08:01:19.2 |
HIP 57806 |
19.76 |
| 2026-06-03 12:00 |
11:52:34.11 |
-08:01:21.0 |
HIP 57806 |
20.68 |
| 2026-06-04 00:00 |
11:52:37.98 |
-08:01:23.6 |
HIP 57806 |
21.63 |
| 2026-06-04 12:00 |
11:52:42.00 |
-08:01:27.2 |
HIP 57806 |
22.63 |
| 2026-06-05 00:00 |
11:52:46.17 |
-08:01:31.7 |
HIP 57806 |
23.67 |
| 2026-06-05 12:00 |
11:52:50.49 |
-08:01:37.1 |
HIP 57806 |
24.74 |
| 2026-06-06 00:00 |
11:52:54.96 |
-08:01:43.4 |
HIP 57806 |
25.85 |
| 2026-06-06 12:00 |
11:52:59.59 |
-08:01:50.6 |
HIP 57917 |
26.29 |
| 2026-06-07 00:00 |
11:53:04.36 |
-08:01:58.8 |
HIP 57917 |
26.61 |
| 2026-06-07 12:00 |
11:53:09.28 |
-08:02:07.8 |
HIP 57917 |
27.00 |
| 2026-06-08 00:00 |
11:53:14.35 |
-08:02:17.8 |
HIP 57917 |
27.47 |
| 2026-06-08 12:00 |
11:53:19.57 |
-08:02:28.7 |
HIP 57917 |
28.01 |
| 2026-06-09 00:00 |
11:53:24.94 |
-08:02:40.5 |
HIP 57917 |
28.63 |
| 2026-06-09 12:00 |
11:53:30.46 |
-08:02:53.3 |
HIP 57917 |
29.32 |
| 2026-06-10 00:00 |
11:53:36.12 |
-08:03:06.9 |
HIP 57917 |
30.10 |
| 2026-06-10 12:00 |
11:53:41.93 |
-08:03:21.6 |
HIP 57917 |
30.95 |
| 2026-06-11 00:00 |
11:53:47.89 |
-08:03:37.1 |
HIP 58163 |
29.66 |
| 2026-06-11 12:00 |
11:53:54.00 |
-08:03:53.5 |
HIP 58163 |
28.13 |
| 2026-06-12 00:00 |
11:54:00.25 |
-08:04:10.9 |
HIP 58163 |
26.57 |
| 2026-06-12 12:00 |
11:54:06.65 |
-08:04:29.3 |
HIP 58163 |
24.97 |
| 2026-06-13 00:00 |
11:54:13.20 |
-08:04:48.5 |
HIP 58163 |
23.33 |
| 2026-06-13 12:00 |
11:54:19.89 |
-08:05:08.7 |
HIP 58163 |
21.65 |
| 2026-06-14 00:00 |
11:54:26.73 |
-08:05:29.8 |
HIP 58163 |
19.94 |
| 2026-06-14 12:00 |
11:54:33.71 |
-08:05:51.9 |
HIP 58163 |
18.19 |
| 2026-06-15 00:00 |
11:54:40.83 |
-08:06:14.9 |
HIP 58163 |
16.41 |
| 2026-06-15 12:00 |
11:54:48.10 |
-08:06:38.8 |
HIP 58163 |
14.59 |
| 2026-06-16 00:00 |
11:54:55.51 |
-08:07:03.6 |
HIP 58163 |
12.74 |
| 2026-06-16 12:00 |
11:55:03.07 |
-08:07:29.4 |
HIP 58163 |
10.86 |
| 2026-06-17 00:00 |
11:55:10.77 |
-08:07:56.2 |
HIP 58163 |
8.96 |
| 2026-06-17 12:00 |
11:55:18.61 |
-08:08:23.8 |
HIP 58163 |
7.06 |
| 2026-06-18 00:00 |
11:55:26.59 |
-08:08:52.4 |
HIP 58163 |
5.18 |
| 2026-06-18 12:00 |
11:55:34.71 |
-08:09:21.9 |
HIP 58163 |
3.46 |
| 2026-06-19 00:00 |
11:55:42.97 |
-08:09:52.3 |
HIP 58163 |
2.35 |
| 2026-06-19 12:00 |
11:55:51.37 |
-08:10:23.7 |
HIP 58163 |
2.84 |
| 2026-06-20 00:00 |
11:55:59.91 |
-08:10:56.0 |
HIP 58163 |
4.47 |
| 2026-06-20 12:00 |
11:56:08.58 |
-08:11:29.2 |
HIP 58163 |
6.47 |
| 2026-06-21 00:00 |
11:56:17.39 |
-08:12:03.3 |
HIP 58163 |
8.61 |
| 2026-06-21 12:00 |
11:56:26.34 |
-08:12:38.4 |
HIP 58163 |
10.84 |
| 2026-06-22 00:00 |
11:56:35.43 |
-08:13:14.4 |
HIP 58163 |
13.11 |