| Parameter |
Value |
| Designation |
C/2025 X1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-12-10T22:31:45.572160Z |
| Orbit solution date (soln_date, UTC) |
2026-05-08T13:42:12Z |
| Obs used |
139 |
| 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) |
2026-01-10.0000000 |
| e |
0.86211795 |
| q (au) |
4.668738 |
| a (au) |
33.860373 |
| i (deg) |
36.957194 |
| Ω (om, deg) |
95.638175 |
| ω (w, deg) |
85.637107 |
| M (ma, deg) |
358.324549 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.378 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.378 |
| 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) |
| 2026-05-12 00:00 |
09:55:19.91 |
+45:35:25.5 |
HIP 48708 |
11.70 |
| 2026-05-12 12:00 |
09:55:35.63 |
+45:32:48.4 |
HIP 48708 |
7.92 |
| 2026-05-13 00:00 |
09:55:51.56 |
+45:30:10.5 |
HIP 48708 |
4.11 |
| 2026-05-13 12:00 |
09:56:07.71 |
+45:27:31.8 |
HIP 48708 |
0.78 |
| 2026-05-14 00:00 |
09:56:24.06 |
+45:24:52.3 |
HIP 48708 |
3.82 |
| 2026-05-14 12:00 |
09:56:40.61 |
+45:22:11.9 |
HIP 48708 |
7.74 |
| 2026-05-15 00:00 |
09:56:57.38 |
+45:19:30.8 |
HIP 48708 |
11.71 |
| 2026-05-15 12:00 |
09:57:14.35 |
+45:16:48.9 |
HIP 48861 |
10.98 |
| 2026-05-16 00:00 |
09:57:31.52 |
+45:14:06.3 |
HIP 48861 |
11.64 |
| 2026-05-16 12:00 |
09:57:48.90 |
+45:11:22.8 |
HIP 48861 |
13.55 |
| 2026-05-17 00:00 |
09:58:06.48 |
+45:08:38.7 |
HIP 48861 |
16.31 |
| 2026-05-17 12:00 |
09:58:24.26 |
+45:05:53.8 |
HIP 48995 |
15.33 |
| 2026-05-18 00:00 |
09:58:42.24 |
+45:03:08.1 |
HIP 48987 |
13.38 |
| 2026-05-18 12:00 |
09:59:00.42 |
+45:00:21.8 |
HIP 48987 |
9.13 |
| 2026-05-19 00:00 |
09:59:18.80 |
+44:57:34.7 |
HIP 48987 |
4.86 |
| 2026-05-19 12:00 |
09:59:37.37 |
+44:54:46.9 |
HIP 48987 |
0.59 |
| 2026-05-20 00:00 |
09:59:56.13 |
+44:51:58.5 |
HIP 48987 |
3.82 |
| 2026-05-20 12:00 |
10:00:15.09 |
+44:49:09.4 |
HIP 48987 |
8.20 |
| 2026-05-21 00:00 |
10:00:34.24 |
+44:46:19.6 |
HIP 48987 |
12.62 |
| 2026-05-21 12:00 |
10:00:53.58 |
+44:43:29.1 |
HIP 48987 |
17.08 |
| 2026-05-22 00:00 |
10:01:13.10 |
+44:40:38.0 |
HIP 49197 |
14.67 |
| 2026-05-22 12:00 |
10:01:32.82 |
+44:37:46.2 |
HIP 49197 |
10.38 |
| 2026-05-23 00:00 |
10:01:52.72 |
+44:34:53.8 |
HIP 49197 |
6.39 |
| 2026-05-23 12:00 |
10:02:12.80 |
+44:32:00.7 |
HIP 49197 |
3.91 |
| 2026-05-24 00:00 |
10:02:33.07 |
+44:29:07.1 |
HIP 49197 |
5.66 |
| 2026-05-24 12:00 |
10:02:53.51 |
+44:26:12.8 |
HIP 49197 |
9.60 |
| 2026-05-25 00:00 |
10:03:14.14 |
+44:23:17.9 |
HIP 49197 |
14.02 |
| 2026-05-25 12:00 |
10:03:34.95 |
+44:20:22.4 |
HIP 49263 |
17.40 |
| 2026-05-26 00:00 |
10:03:55.93 |
+44:17:26.4 |
HIP 49263 |
21.04 |
| 2026-05-26 12:00 |
10:04:17.09 |
+44:14:29.7 |
HIP 49447 |
22.00 |
| 2026-05-27 00:00 |
10:04:38.42 |
+44:11:32.5 |
HIP 49447 |
17.22 |
| 2026-05-27 12:00 |
10:04:59.93 |
+44:08:34.6 |
HIP 49447 |
12.46 |
| 2026-05-28 00:00 |
10:05:21.61 |
+44:05:36.3 |
HIP 49447 |
7.81 |
| 2026-05-28 12:00 |
10:05:43.46 |
+44:02:37.3 |
HIP 49447 |
3.81 |
| 2026-05-29 00:00 |
10:06:05.48 |
+43:59:37.8 |
HIP 49447 |
4.11 |
| 2026-05-29 12:00 |
10:06:27.66 |
+43:56:37.8 |
HIP 49447 |
8.32 |
| 2026-05-30 00:00 |
10:06:50.01 |
+43:53:37.2 |
HIP 49447 |
13.13 |
| 2026-05-30 12:00 |
10:07:12.53 |
+43:50:36.1 |
HIP 49447 |
18.09 |
| 2026-05-31 00:00 |
10:07:35.21 |
+43:47:34.4 |
HIP 49489 |
19.86 |
| 2026-05-31 12:00 |
10:07:58.06 |
+43:44:32.2 |
HIP 49489 |
21.55 |
| 2026-06-01 00:00 |
10:08:21.07 |
+43:41:29.5 |
HIP 49489 |
24.26 |
| 2026-06-01 12:00 |
10:08:44.23 |
+43:38:26.3 |
HIP 49795 |
21.61 |
| 2026-06-02 00:00 |
10:09:07.56 |
+43:35:22.6 |
HIP 49795 |
16.78 |