| Parameter |
Value |
| Designation |
C/2025 X1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-12-10T22:49:17.656320Z |
| Orbit solution date (soln_date, UTC) |
2026-05-28T12:12:16Z |
| Obs used |
143 |
| NEO |
- |
| M1 |
7.200 |
| K1 |
13.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-12-12T15:00:50.889600Z |
| Discovery magnitude (MPC) |
21.04 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2026-01-14.0000000 |
| e |
0.86209784 |
| q (au) |
4.668706 |
| a (au) |
33.855203 |
| i (deg) |
36.957112 |
| Ω (om, deg) |
95.638037 |
| ω (w, deg) |
85.638703 |
| M (ma, deg) |
358.344118 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.369 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.369 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
12:11:09.54 |
+31:14:17.5 |
HIP 59620 |
35.24 |
| 2026-09-20 12:00 |
12:11:47.12 |
+31:11:14.8 |
HIP 59620 |
26.73 |
| 2026-09-21 00:00 |
12:12:24.71 |
+31:08:12.6 |
HIP 59620 |
18.30 |
| 2026-09-21 12:00 |
12:13:02.30 |
+31:05:11.1 |
HIP 59620 |
10.18 |
| 2026-09-22 00:00 |
12:13:39.89 |
+31:02:10.1 |
HIP 59620 |
4.49 |
| 2026-09-22 12:00 |
12:14:17.48 |
+30:59:09.6 |
HIP 59620 |
9.20 |
| 2026-09-23 00:00 |
12:14:55.07 |
+30:56:09.8 |
HIP 59666 |
12.21 |
| 2026-09-23 12:00 |
12:15:32.66 |
+30:53:10.6 |
HIP 59666 |
18.51 |
| 2026-09-24 00:00 |
12:16:10.24 |
+30:50:11.9 |
HIP 59850 |
21.03 |
| 2026-09-24 12:00 |
12:16:47.82 |
+30:47:13.8 |
HIP 59850 |
24.35 |
| 2026-09-25 00:00 |
12:17:25.40 |
+30:44:16.4 |
HIP 59936 |
21.76 |
| 2026-09-25 12:00 |
12:18:02.98 |
+30:41:19.6 |
HIP 60050 |
17.26 |
| 2026-09-26 00:00 |
12:18:40.56 |
+30:38:23.3 |
HIP 60050 |
10.72 |
| 2026-09-26 12:00 |
12:19:18.13 |
+30:35:27.7 |
HIP 60050 |
8.95 |
| 2026-09-27 00:00 |
12:19:55.69 |
+30:32:32.8 |
HIP 60139 |
3.40 |
| 2026-09-27 12:00 |
12:20:33.26 |
+30:29:38.4 |
HIP 60139 |
7.57 |
| 2026-09-28 00:00 |
12:21:10.82 |
+30:26:44.7 |
HIP 60139 |
15.84 |
| 2026-09-28 12:00 |
12:21:48.37 |
+30:23:51.6 |
HIP 60400 |
20.78 |
| 2026-09-29 00:00 |
12:22:25.92 |
+30:20:59.2 |
HIP 60400 |
17.71 |
| 2026-09-29 12:00 |
12:23:03.46 |
+30:18:07.5 |
HIP 60400 |
18.51 |
| 2026-09-30 00:00 |
12:23:41.00 |
+30:15:16.4 |
HIP 60400 |
22.77 |
| 2026-09-30 12:00 |
12:24:18.53 |
+30:12:25.9 |
HIP 60597 |
19.45 |
| 2026-10-01 00:00 |
12:24:56.06 |
+30:09:36.2 |
HIP 60597 |
13.09 |
| 2026-10-01 12:00 |
12:25:33.58 |
+30:06:47.1 |
HIP 60669 |
6.24 |
| 2026-10-02 00:00 |
12:26:11.09 |
+30:03:58.7 |
HIP 60669 |
3.95 |
| 2026-10-02 12:00 |
12:26:48.60 |
+30:01:11.0 |
HIP 60669 |
11.81 |
| 2026-10-03 00:00 |
12:27:26.09 |
+29:58:24.0 |
HIP 60826 |
12.39 |
| 2026-10-03 12:00 |
12:28:03.58 |
+29:55:37.7 |
HIP 60826 |
6.57 |
| 2026-10-04 00:00 |
12:28:41.06 |
+29:52:52.1 |
HIP 60826 |
8.95 |
| 2026-10-04 12:00 |
12:29:18.53 |
+29:50:07.3 |
HIP 60955 |
12.38 |
| 2026-10-05 00:00 |
12:29:56.00 |
+29:47:23.2 |
HIP 60955 |
14.23 |
| 2026-10-05 12:00 |
12:30:33.45 |
+29:44:39.8 |
HIP 60955 |
19.95 |
| 2026-10-06 00:00 |
12:31:10.89 |
+29:41:57.2 |
HIP 61147 |
24.66 |
| 2026-10-06 12:00 |
12:31:48.32 |
+29:39:15.3 |
HIP 61147 |
20.41 |
| 2026-10-07 00:00 |
12:32:25.74 |
+29:36:34.2 |
HIP 61147 |
19.30 |
| 2026-10-07 12:00 |
12:33:03.14 |
+29:33:53.9 |
HIP 61147 |
21.82 |
| 2026-10-08 00:00 |
12:33:40.53 |
+29:31:14.3 |
HIP 61147 |
26.96 |
| 2026-10-08 12:00 |
12:34:17.91 |
+29:28:35.5 |
HIP 61503 |
23.47 |
| 2026-10-09 00:00 |
12:34:55.28 |
+29:25:57.5 |
HIP 61503 |
15.35 |
| 2026-10-09 12:00 |
12:35:32.63 |
+29:23:20.4 |
HIP 61503 |
8.14 |
| 2026-10-10 00:00 |
12:36:09.97 |
+29:20:44.0 |
HIP 61503 |
6.53 |
| 2026-10-10 12:00 |
12:36:47.29 |
+29:18:08.4 |
HIP 61503 |
12.83 |
| 2026-10-11 00:00 |
12:37:24.59 |
+29:15:33.7 |
HIP 61503 |
20.78 |