| Parameter |
Value |
| Designation |
C/2025 E1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-09-23T17:12:33.793920Z |
| Orbit solution date (soln_date, UTC) |
2026-03-31T09:42:18Z |
| Obs used |
131 |
| NEO |
- |
| M1 |
6.400 |
| K1 |
13.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-03-02T10:18:16.963200Z |
| Discovery magnitude (MPC) |
20.69 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2025-11-17.0000000 |
| e |
0.99740301 |
| q (au) |
3.998169 |
| a (au) |
1539.536926 |
| i (deg) |
69.061504 |
| Ω (om, deg) |
344.593495 |
| ω (w, deg) |
274.420527 |
| M (ma, deg) |
359.994930 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.536 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.536 |
| 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) |
| 2026-03-26 00:00 |
09:49:43.60 |
-68:55:50.0 |
HIP 48650 |
30.64 |
| 2026-03-26 12:00 |
09:48:23.39 |
-68:55:42.2 |
HIP 47879 |
25.96 |
| 2026-03-27 00:00 |
09:47:03.57 |
-68:55:29.1 |
HIP 47879 |
22.10 |
| 2026-03-27 12:00 |
09:45:44.16 |
-68:55:11.0 |
HIP 47879 |
20.10 |
| 2026-03-28 00:00 |
09:44:25.19 |
-68:54:47.9 |
HIP 47879 |
20.49 |
| 2026-03-28 12:00 |
09:43:06.68 |
-68:54:19.7 |
HIP 47879 |
23.11 |
| 2026-03-29 00:00 |
09:41:48.63 |
-68:53:46.6 |
HIP 47238 |
22.42 |
| 2026-03-29 12:00 |
09:40:31.08 |
-68:53:08.6 |
HIP 47238 |
15.60 |
| 2026-03-30 00:00 |
09:39:14.03 |
-68:52:25.9 |
HIP 47238 |
9.13 |
| 2026-03-30 12:00 |
09:37:57.50 |
-68:51:38.4 |
HIP 47238 |
4.61 |
| 2026-03-31 00:00 |
09:36:41.51 |
-68:50:46.2 |
HIP 47238 |
7.46 |
| 2026-03-31 12:00 |
09:35:26.08 |
-68:49:49.4 |
HIP 47238 |
13.60 |
| 2026-04-01 00:00 |
09:34:11.22 |
-68:48:48.1 |
HIP 47238 |
20.19 |
| 2026-04-01 12:00 |
09:32:56.95 |
-68:47:42.2 |
HIP 47238 |
26.88 |
| 2026-04-02 00:00 |
09:31:43.27 |
-68:46:32.0 |
HIP 47238 |
33.59 |
| 2026-04-02 12:00 |
09:30:30.21 |
-68:45:17.4 |
HIP 46667 |
34.38 |
| 2026-04-03 00:00 |
09:29:17.78 |
-68:43:58.6 |
HIP 46205 |
31.38 |
| 2026-04-03 12:00 |
09:28:05.99 |
-68:42:35.5 |
HIP 46205 |
26.04 |
| 2026-04-04 00:00 |
09:26:54.86 |
-68:41:08.4 |
HIP 46205 |
21.43 |
| 2026-04-04 12:00 |
09:25:44.39 |
-68:39:37.2 |
HIP 46205 |
18.08 |
| 2026-04-05 00:00 |
09:24:34.61 |
-68:38:02.0 |
HIP 46205 |
16.73 |
| 2026-04-05 12:00 |
09:23:25.51 |
-68:36:22.8 |
HIP 46205 |
17.79 |
| 2026-04-06 00:00 |
09:22:17.11 |
-68:34:39.9 |
HIP 46205 |
20.87 |
| 2026-04-06 12:00 |
09:21:09.43 |
-68:32:53.2 |
HIP 45571 |
22.79 |
| 2026-04-07 00:00 |
09:20:02.47 |
-68:31:02.8 |
HIP 45571 |
18.26 |
| 2026-04-07 12:00 |
09:18:56.24 |
-68:29:08.8 |
HIP 45571 |
15.19 |
| 2026-04-08 00:00 |
09:17:50.75 |
-68:27:11.3 |
HIP 45571 |
14.51 |
| 2026-04-08 12:00 |
09:16:46.01 |
-68:25:10.4 |
HIP 45365 |
14.00 |
| 2026-04-09 00:00 |
09:15:42.03 |
-68:23:06.0 |
HIP 45365 |
8.19 |
| 2026-04-09 12:00 |
09:14:38.81 |
-68:20:58.4 |
HIP 45365 |
3.95 |
| 2026-04-10 00:00 |
09:13:36.36 |
-68:18:47.6 |
HIP 45365 |
6.35 |
| 2026-04-10 12:00 |
09:12:34.70 |
-68:16:33.6 |
HIP 45365 |
11.83 |
| 2026-04-11 00:00 |
09:11:33.82 |
-68:14:16.6 |
HIP 45024 |
8.64 |
| 2026-04-11 12:00 |
09:10:33.73 |
-68:11:56.5 |
HIP 45024 |
7.38 |
| 2026-04-12 00:00 |
09:09:34.44 |
-68:09:33.6 |
HIP 45024 |
10.36 |
| 2026-04-12 12:00 |
09:08:35.95 |
-68:07:07.9 |
HIP 45024 |
15.23 |
| 2026-04-13 00:00 |
09:07:38.26 |
-68:04:39.5 |
HIP 45024 |
20.66 |
| 2026-04-13 12:00 |
09:06:41.39 |
-68:02:08.4 |
HIP 45024 |
26.27 |
| 2026-04-14 00:00 |
09:05:45.33 |
-67:59:34.7 |
HIP 44494 |
24.68 |
| 2026-04-14 12:00 |
09:04:50.10 |
-67:56:58.6 |
HIP 44494 |
20.43 |
| 2026-04-15 00:00 |
09:03:55.68 |
-67:54:20.0 |
HIP 44494 |
17.08 |
| 2026-04-15 12:00 |
09:03:02.08 |
-67:51:39.1 |
HIP 44241 |
14.70 |
| 2026-04-16 00:00 |
09:02:09.32 |
-67:48:55.9 |
HIP 44241 |
11.69 |