| Parameter |
Value |
| Designation |
C/2025 Y3 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-01-13T16:51:06.096960Z |
| Orbit solution date (soln_date, UTC) |
2026-01-20T12:12:02Z |
| Obs used |
27 |
| NEO |
- |
| M1 |
16.800 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-12-27T09:18:59.788800Z |
| Discovery magnitude (MPC) |
21.65 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2026-01-02.0000000 |
| e |
1.00074191 |
| q (au) |
2.227313 |
| a (au) |
-3002.143709 |
| i (deg) |
89.548987 |
| Ω (om, deg) |
272.966956 |
| ω (w, deg) |
219.383051 |
| M (ma, deg) |
-0.000070 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.597 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.597 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.800 |
| 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) |
| 2026-09-20 00:00 |
11:57:13.25 |
-74:46:26.5 |
HIP 57965 |
20.78 |
| 2026-09-20 12:00 |
12:00:21.27 |
-74:48:18.4 |
HIP 58717 |
9.02 |
| 2026-09-21 00:00 |
12:03:29.35 |
-74:50:04.0 |
HIP 58717 |
4.83 |
| 2026-09-21 12:00 |
12:06:37.44 |
-74:51:43.4 |
HIP 58717 |
16.55 |
| 2026-09-22 00:00 |
12:09:45.50 |
-74:53:16.6 |
HIP 59499 |
9.71 |
| 2026-09-22 12:00 |
12:12:53.51 |
-74:54:43.7 |
HIP 59499 |
3.42 |
| 2026-09-23 00:00 |
12:16:01.43 |
-74:56:04.6 |
HIP 59778 |
12.49 |
| 2026-09-23 12:00 |
12:19:09.22 |
-74:57:19.5 |
HIP 59778 |
19.85 |
| 2026-09-24 00:00 |
12:22:16.85 |
-74:58:28.2 |
HIP 60553 |
10.83 |
| 2026-09-24 12:00 |
12:25:24.28 |
-74:59:31.0 |
HIP 60553 |
4.34 |
| 2026-09-25 00:00 |
12:28:31.48 |
-75:00:27.8 |
HIP 60553 |
14.69 |
| 2026-09-25 12:00 |
12:31:38.42 |
-75:01:18.6 |
HIP 61217 |
22.12 |
| 2026-09-26 00:00 |
12:34:45.06 |
-75:02:03.6 |
HIP 61284 |
21.67 |
| 2026-09-26 12:00 |
12:37:51.37 |
-75:02:42.7 |
HIP 61738 |
20.23 |
| 2026-09-27 00:00 |
12:40:57.31 |
-75:03:16.0 |
HIP 61738 |
20.07 |
| 2026-09-27 12:00 |
12:44:02.86 |
-75:03:43.7 |
HIP 62289 |
10.21 |
| 2026-09-28 00:00 |
12:47:07.98 |
-75:04:05.6 |
HIP 62289 |
8.44 |
| 2026-09-28 12:00 |
12:50:12.64 |
-75:04:22.0 |
HIP 62539 |
15.83 |
| 2026-09-29 00:00 |
12:53:16.82 |
-75:04:32.7 |
HIP 62539 |
22.41 |
| 2026-09-29 12:00 |
12:56:20.48 |
-75:04:38.0 |
HIP 62539 |
32.12 |
| 2026-09-30 00:00 |
12:59:23.59 |
-75:04:37.9 |
HIP 63899 |
27.05 |
| 2026-09-30 12:00 |
13:02:26.12 |
-75:04:32.4 |
HIP 63899 |
16.93 |
| 2026-10-01 00:00 |
13:05:28.05 |
-75:04:21.6 |
HIP 63899 |
10.92 |
| 2026-10-01 12:00 |
13:08:29.36 |
-75:04:05.6 |
HIP 63899 |
15.07 |
| 2026-10-02 00:00 |
13:11:30.01 |
-75:03:44.4 |
HIP 64598 |
13.02 |
| 2026-10-02 12:00 |
13:14:29.97 |
-75:03:18.1 |
HIP 64598 |
6.97 |
| 2026-10-03 00:00 |
13:17:29.24 |
-75:02:46.8 |
HIP 64972 |
13.67 |
| 2026-10-03 12:00 |
13:20:27.77 |
-75:02:10.6 |
HIP 64972 |
13.09 |
| 2026-10-04 00:00 |
13:23:25.55 |
-75:01:29.5 |
HIP 65468 |
10.56 |
| 2026-10-04 12:00 |
13:26:22.56 |
-75:00:43.6 |
HIP 65468 |
8.93 |
| 2026-10-05 00:00 |
13:29:18.77 |
-74:59:53.0 |
HIP 65832 |
5.78 |
| 2026-10-05 12:00 |
13:32:14.16 |
-74:58:57.8 |
HIP 65832 |
10.89 |
| 2026-10-06 00:00 |
13:35:08.72 |
-74:57:58.0 |
HIP 66111 |
14.70 |
| 2026-10-06 12:00 |
13:38:02.42 |
-74:56:53.7 |
HIP 66806 |
17.23 |
| 2026-10-07 00:00 |
13:40:55.25 |
-74:55:45.1 |
HIP 66852 |
10.16 |
| 2026-10-07 12:00 |
13:43:47.19 |
-74:54:32.0 |
HIP 66852 |
10.52 |
| 2026-10-08 00:00 |
13:46:38.23 |
-74:53:14.8 |
HIP 67478 |
11.94 |
| 2026-10-08 12:00 |
13:49:28.34 |
-74:51:53.4 |
HIP 67478 |
2.81 |
| 2026-10-09 00:00 |
13:52:17.52 |
-74:50:27.8 |
HIP 67478 |
11.05 |
| 2026-10-09 12:00 |
13:55:05.74 |
-74:48:58.3 |
HIP 68122 |
15.47 |
| 2026-10-10 00:00 |
13:57:53.00 |
-74:47:24.8 |
HIP 68122 |
13.12 |
| 2026-10-10 12:00 |
14:00:39.29 |
-74:45:47.5 |
HIP 68122 |
18.73 |
| 2026-10-11 00:00 |
14:03:24.59 |
-74:44:06.4 |
HIP 69002 |
16.79 |