| Parameter |
Value |
| Designation |
C/2025 E1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-09-23T17:03:27.020160Z |
| Orbit solution date (soln_date, UTC) |
2026-05-05T09:12:15Z |
| Obs used |
233 |
| NEO |
- |
| M1 |
6.600 |
| K1 |
13.250 |
| 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) |
2026-01-23.0000000 |
| e |
0.99750791 |
| q (au) |
3.998118 |
| a (au) |
1604.326070 |
| i (deg) |
69.060607 |
| Ω (om, deg) |
344.592327 |
| ω (w, deg) |
274.421532 |
| M (ma, deg) |
359.996262 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.132 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.132 |
| n |
6.000 |
| gf |
0.879 |
| gb |
-0.979 |
| k |
1.000 |
| δ90 |
1.000 |
| 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) |
| 2026-05-12 00:00 |
08:34:35.21 |
-65:06:06.5 |
HIP 42188 |
19.88 |
| 2026-05-12 12:00 |
08:34:22.36 |
-65:03:03.2 |
HIP 42188 |
18.11 |
| 2026-05-13 00:00 |
08:34:10.12 |
-65:00:00.9 |
HIP 42188 |
16.78 |
| 2026-05-13 12:00 |
08:33:58.50 |
-64:56:59.8 |
HIP 42188 |
15.99 |
| 2026-05-14 00:00 |
08:33:47.50 |
-64:53:59.9 |
HIP 42188 |
15.80 |
| 2026-05-14 12:00 |
08:33:37.10 |
-64:51:01.1 |
HIP 42188 |
16.19 |
| 2026-05-15 00:00 |
08:33:27.31 |
-64:48:03.6 |
HIP 42188 |
17.12 |
| 2026-05-15 12:00 |
08:33:18.11 |
-64:45:07.5 |
HIP 42188 |
18.47 |
| 2026-05-16 00:00 |
08:33:09.51 |
-64:42:12.6 |
HIP 42188 |
20.15 |
| 2026-05-16 12:00 |
08:33:01.49 |
-64:39:19.2 |
HIP 42203 |
21.10 |
| 2026-05-17 00:00 |
08:32:54.05 |
-64:36:27.1 |
HIP 42203 |
22.12 |
| 2026-05-17 12:00 |
08:32:47.18 |
-64:33:36.6 |
HIP 42203 |
23.42 |
| 2026-05-18 00:00 |
08:32:40.89 |
-64:30:47.5 |
HIP 42203 |
24.94 |
| 2026-05-18 12:00 |
08:32:35.16 |
-64:28:00.0 |
HIP 42203 |
26.62 |
| 2026-05-19 00:00 |
08:32:29.98 |
-64:25:14.0 |
HIP 42229 |
28.15 |
| 2026-05-19 12:00 |
08:32:25.36 |
-64:22:29.6 |
HIP 42229 |
27.92 |
| 2026-05-20 00:00 |
08:32:21.28 |
-64:19:46.9 |
HIP 42229 |
27.92 |
| 2026-05-20 12:00 |
08:32:17.75 |
-64:17:05.9 |
HIP 41969 |
27.26 |
| 2026-05-21 00:00 |
08:32:14.75 |
-64:14:26.5 |
HIP 41969 |
24.79 |
| 2026-05-21 12:00 |
08:32:12.28 |
-64:11:48.9 |
HIP 41969 |
22.37 |
| 2026-05-22 00:00 |
08:32:10.34 |
-64:09:13.1 |
HIP 41969 |
20.01 |
| 2026-05-22 12:00 |
08:32:08.91 |
-64:06:39.0 |
HIP 41969 |
17.73 |
| 2026-05-23 00:00 |
08:32:08.00 |
-64:04:06.8 |
HIP 41969 |
15.54 |
| 2026-05-23 12:00 |
08:32:07.59 |
-64:01:36.4 |
HIP 41969 |
13.45 |
| 2026-05-24 00:00 |
08:32:07.69 |
-63:59:08.0 |
HIP 41969 |
11.53 |
| 2026-05-24 12:00 |
08:32:08.29 |
-63:56:41.4 |
HIP 41969 |
9.83 |
| 2026-05-25 00:00 |
08:32:09.38 |
-63:54:16.7 |
HIP 41969 |
8.46 |
| 2026-05-25 12:00 |
08:32:10.96 |
-63:51:54.0 |
HIP 41969 |
7.59 |
| 2026-05-26 00:00 |
08:32:13.02 |
-63:49:33.2 |
HIP 41969 |
7.35 |
| 2026-05-26 12:00 |
08:32:15.56 |
-63:47:14.5 |
HIP 41969 |
7.79 |
| 2026-05-27 00:00 |
08:32:18.57 |
-63:44:57.8 |
HIP 41969 |
8.77 |
| 2026-05-27 12:00 |
08:32:22.06 |
-63:42:43.1 |
HIP 41969 |
10.13 |
| 2026-05-28 00:00 |
08:32:26.00 |
-63:40:30.5 |
HIP 41969 |
11.73 |
| 2026-05-28 12:00 |
08:32:30.41 |
-63:38:20.0 |
HIP 41969 |
13.45 |
| 2026-05-29 00:00 |
08:32:35.28 |
-63:36:11.6 |
HIP 41969 |
15.26 |
| 2026-05-29 12:00 |
08:32:40.59 |
-63:34:05.3 |
HIP 42002 |
16.47 |
| 2026-05-30 00:00 |
08:32:46.36 |
-63:32:01.1 |
HIP 42002 |
14.32 |
| 2026-05-30 12:00 |
08:32:52.56 |
-63:29:59.1 |
HIP 42002 |
12.18 |
| 2026-05-31 00:00 |
08:32:59.21 |
-63:27:59.3 |
HIP 42002 |
10.06 |
| 2026-05-31 12:00 |
08:33:06.29 |
-63:26:01.7 |
HIP 42002 |
7.96 |
| 2026-06-01 00:00 |
08:33:13.80 |
-63:24:06.4 |
HIP 42002 |
5.86 |
| 2026-06-01 12:00 |
08:33:21.75 |
-63:22:13.2 |
HIP 42002 |
3.78 |
| 2026-06-02 00:00 |
08:33:30.11 |
-63:20:22.3 |
HIP 42002 |
1.72 |