| 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) |
| 2026-07-29 00:00 |
11:06:22.90 |
+37:11:00.3 |
HIP 54343 |
27.91 |
| 2026-07-29 12:00 |
11:06:57.77 |
+37:07:29.3 |
HIP 54343 |
23.31 |
| 2026-07-30 00:00 |
11:07:32.69 |
+37:03:58.3 |
HIP 54422 |
19.70 |
| 2026-07-30 12:00 |
11:08:07.66 |
+37:00:27.4 |
HIP 54422 |
14.57 |
| 2026-07-31 00:00 |
11:08:42.68 |
+36:56:56.4 |
HIP 54422 |
12.61 |
| 2026-07-31 12:00 |
11:09:17.76 |
+36:53:25.5 |
HIP 54422 |
15.13 |
| 2026-08-01 00:00 |
11:09:52.88 |
+36:49:54.6 |
HIP 54422 |
20.56 |
| 2026-08-01 12:00 |
11:10:28.05 |
+36:46:23.7 |
HIP 54726 |
22.54 |
| 2026-08-02 00:00 |
11:11:03.28 |
+36:42:52.8 |
HIP 54726 |
17.87 |
| 2026-08-02 12:00 |
11:11:38.55 |
+36:39:22.0 |
HIP 54726 |
15.95 |
| 2026-08-03 00:00 |
11:12:13.87 |
+36:35:51.2 |
HIP 54726 |
17.71 |
| 2026-08-03 12:00 |
11:12:49.23 |
+36:32:20.5 |
HIP 54726 |
22.31 |
| 2026-08-04 00:00 |
11:13:24.65 |
+36:28:49.8 |
HIP 54726 |
28.42 |
| 2026-08-04 12:00 |
11:14:00.11 |
+36:25:19.1 |
HIP 55009 |
21.56 |
| 2026-08-05 00:00 |
11:14:35.62 |
+36:21:48.5 |
HIP 55009 |
14.33 |
| 2026-08-05 12:00 |
11:15:11.17 |
+36:18:18.0 |
HIP 55009 |
8.50 |
| 2026-08-06 00:00 |
11:15:46.77 |
+36:14:47.5 |
HIP 55009 |
8.13 |
| 2026-08-06 12:00 |
11:16:22.41 |
+36:11:17.1 |
HIP 55009 |
13.69 |
| 2026-08-07 00:00 |
11:16:58.10 |
+36:07:46.7 |
HIP 55009 |
20.90 |
| 2026-08-07 12:00 |
11:17:33.83 |
+36:04:16.5 |
HIP 55251 |
19.75 |
| 2026-08-08 00:00 |
11:18:09.60 |
+36:00:46.3 |
HIP 55251 |
11.78 |
| 2026-08-08 12:00 |
11:18:45.42 |
+35:57:16.2 |
HIP 55251 |
4.08 |
| 2026-08-09 00:00 |
11:19:21.28 |
+35:53:46.2 |
HIP 55251 |
4.91 |
| 2026-08-09 12:00 |
11:19:57.18 |
+35:50:16.3 |
HIP 55251 |
12.72 |
| 2026-08-10 00:00 |
11:20:33.12 |
+35:46:46.5 |
HIP 55462 |
14.01 |
| 2026-08-10 12:00 |
11:21:09.10 |
+35:43:16.8 |
HIP 55462 |
6.17 |
| 2026-08-11 00:00 |
11:21:45.12 |
+35:39:47.2 |
HIP 55462 |
3.31 |
| 2026-08-11 12:00 |
11:22:21.18 |
+35:36:17.8 |
HIP 55462 |
10.75 |
| 2026-08-12 00:00 |
11:22:57.28 |
+35:32:48.5 |
HIP 55506 |
16.42 |
| 2026-08-12 12:00 |
11:23:33.42 |
+35:29:19.3 |
HIP 55506 |
20.09 |
| 2026-08-13 00:00 |
11:24:09.60 |
+35:25:50.2 |
HIP 55755 |
22.50 |
| 2026-08-13 12:00 |
11:24:45.81 |
+35:22:21.3 |
HIP 55755 |
15.05 |
| 2026-08-14 00:00 |
11:25:22.06 |
+35:18:52.6 |
HIP 55755 |
8.97 |
| 2026-08-14 12:00 |
11:25:58.34 |
+35:15:24.0 |
HIP 55755 |
8.25 |
| 2026-08-15 00:00 |
11:26:34.66 |
+35:11:55.6 |
HIP 55755 |
13.79 |
| 2026-08-15 12:00 |
11:27:11.02 |
+35:08:27.3 |
HIP 55939 |
16.25 |
| 2026-08-16 00:00 |
11:27:47.40 |
+35:04:59.2 |
HIP 55939 |
17.29 |
| 2026-08-16 12:00 |
11:28:23.82 |
+35:01:31.4 |
HIP 55939 |
21.64 |
| 2026-08-17 00:00 |
11:29:00.27 |
+34:58:03.6 |
HIP 56155 |
23.55 |
| 2026-08-17 12:00 |
11:29:36.76 |
+34:54:36.1 |
HIP 56155 |
19.99 |
| 2026-08-18 00:00 |
11:30:13.27 |
+34:51:08.8 |
HIP 56155 |
19.47 |
| 2026-08-18 12:00 |
11:30:49.82 |
+34:47:41.7 |
HIP 56184 |
15.69 |
| 2026-08-19 00:00 |
11:31:26.39 |
+34:44:14.7 |
HIP 56184 |
13.26 |