| Parameter |
Value |
| Designation |
C/2025 E1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-09-23T17:02:00.620160Z |
| Orbit solution date (soln_date, UTC) |
2026-09-21T07:12:14Z |
| Obs used |
290 |
| NEO |
- |
| M1 |
7.100 |
| K1 |
12.500 |
| 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) |
2026-02-20.0000000 |
| e |
0.99753819 |
| q (au) |
3.998109 |
| a (au) |
1624.054051 |
| i (deg) |
69.060252 |
| Ω (om, deg) |
344.591738 |
| ω (w, deg) |
274.421933 |
| M (ma, deg) |
359.996752 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.928 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.928 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-0.718 |
| k |
0.800 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
11:17:49.63 |
-73:52:52.0 |
HIP 55300 |
10.20 |
| 2026-09-20 12:00 |
11:19:28.25 |
-73:59:25.2 |
HIP 55300 |
0.93 |
| 2026-09-21 00:00 |
11:21:07.99 |
-74:05:58.6 |
HIP 55300 |
8.77 |
| 2026-09-21 12:00 |
11:22:48.89 |
-74:12:32.3 |
HIP 55237 |
16.87 |
| 2026-09-22 00:00 |
11:24:30.96 |
-74:19:06.3 |
HIP 55902 |
13.42 |
| 2026-09-22 12:00 |
11:26:14.23 |
-74:25:40.3 |
HIP 55902 |
13.13 |
| 2026-09-23 00:00 |
11:27:58.73 |
-74:32:14.5 |
HIP 56144 |
10.84 |
| 2026-09-23 12:00 |
11:29:44.48 |
-74:38:48.7 |
HIP 56144 |
3.71 |
| 2026-09-24 00:00 |
11:31:31.51 |
-74:45:22.9 |
HIP 56144 |
9.79 |
| 2026-09-24 12:00 |
11:33:19.84 |
-74:51:57.0 |
HIP 56144 |
19.11 |
| 2026-09-25 00:00 |
11:35:09.51 |
-74:58:30.9 |
HIP 57065 |
27.50 |
| 2026-09-25 12:00 |
11:37:00.54 |
-75:05:04.7 |
HIP 57065 |
19.01 |
| 2026-09-26 00:00 |
11:38:52.96 |
-75:11:38.1 |
HIP 57065 |
12.49 |
| 2026-09-26 12:00 |
11:40:46.80 |
-75:18:11.2 |
HIP 57092 |
7.21 |
| 2026-09-27 00:00 |
11:42:42.10 |
-75:24:44.0 |
HIP 57092 |
11.23 |
| 2026-09-27 12:00 |
11:44:38.87 |
-75:31:16.2 |
HIP 57092 |
19.84 |
| 2026-09-28 00:00 |
11:46:37.16 |
-75:37:47.9 |
HIP 57715 |
13.25 |
| 2026-09-28 12:00 |
11:48:37.00 |
-75:44:19.0 |
HIP 57715 |
8.34 |
| 2026-09-29 00:00 |
11:50:38.42 |
-75:50:49.4 |
HIP 57715 |
12.62 |
| 2026-09-29 12:00 |
11:52:41.45 |
-75:57:19.0 |
HIP 57661 |
16.77 |
| 2026-09-30 00:00 |
11:54:46.13 |
-76:03:47.8 |
HIP 58490 |
18.02 |
| 2026-09-30 12:00 |
11:56:52.49 |
-76:10:15.7 |
HIP 58490 |
13.49 |
| 2026-10-01 00:00 |
11:59:00.57 |
-76:16:42.5 |
HIP 58490 |
15.48 |
| 2026-10-01 12:00 |
12:01:10.40 |
-76:23:08.3 |
HIP 58905 |
14.99 |
| 2026-10-02 00:00 |
12:03:22.03 |
-76:29:33.0 |
HIP 58905 |
5.19 |
| 2026-10-02 12:00 |
12:05:35.48 |
-76:35:56.3 |
HIP 58905 |
5.57 |
| 2026-10-03 00:00 |
12:07:50.80 |
-76:42:18.3 |
HIP 59245 |
6.16 |
| 2026-10-03 12:00 |
12:10:08.02 |
-76:48:38.9 |
HIP 59245 |
10.90 |
| 2026-10-04 00:00 |
12:12:27.19 |
-76:54:58.0 |
HIP 59245 |
20.12 |
| 2026-10-04 12:00 |
12:14:48.33 |
-77:01:15.4 |
HIP 60119 |
21.40 |
| 2026-10-05 00:00 |
12:17:11.50 |
-77:07:31.1 |
HIP 60119 |
21.32 |
| 2026-10-05 12:00 |
12:19:36.73 |
-77:13:45.0 |
HIP 60526 |
16.14 |
| 2026-10-06 00:00 |
12:22:04.06 |
-77:19:57.0 |
HIP 60526 |
10.63 |
| 2026-10-06 12:00 |
12:24:33.53 |
-77:26:06.9 |
HIP 60526 |
13.24 |
| 2026-10-07 00:00 |
12:27:05.19 |
-77:32:14.7 |
HIP 61183 |
19.09 |
| 2026-10-07 12:00 |
12:29:39.06 |
-77:38:20.2 |
HIP 61183 |
8.91 |
| 2026-10-08 00:00 |
12:32:15.21 |
-77:44:23.3 |
HIP 61183 |
2.33 |
| 2026-10-08 12:00 |
12:34:53.65 |
-77:50:24.0 |
HIP 61183 |
12.00 |
| 2026-10-09 00:00 |
12:37:34.44 |
-77:56:22.0 |
HIP 61792 |
9.27 |
| 2026-10-09 12:00 |
12:40:17.62 |
-78:02:17.3 |
HIP 61864 |
5.54 |
| 2026-10-10 00:00 |
12:43:03.23 |
-78:08:09.7 |
HIP 61864 |
13.40 |
| 2026-10-10 12:00 |
12:45:51.30 |
-78:13:59.1 |
HIP 62362 |
20.81 |
| 2026-10-11 00:00 |
12:48:41.89 |
-78:19:45.3 |
HIP 62362 |
15.90 |