| Parameter |
Value |
| Designation |
C/2012 E3 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2011-05-12T22:05:22.326720Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:05Z |
| Obs used |
74 |
| NEO |
- |
| M1 |
9.900 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-03-29.0000000 |
| e |
0.98271491 |
| q (au) |
3.827319 |
| a (au) |
221.423057 |
| i (deg) |
105.658608 |
| Ω (om, deg) |
5.530998 |
| ω (w, deg) |
103.515422 |
| M (ma, deg) |
0.096047 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.440 + 2.856\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.440 |
| n |
2.856 |
| gf |
0.814 |
| gb |
-0.500 |
| k |
0.976 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
08:38:01.00 |
-44:42:46.9 |
HIP 42340 |
13.66 |
| 2026-05-12 12:00 |
08:38:01.80 |
-44:42:00.1 |
HIP 42340 |
12.90 |
| 2026-05-13 00:00 |
08:38:02.64 |
-44:41:13.5 |
HIP 42340 |
12.14 |
| 2026-05-13 12:00 |
08:38:03.53 |
-44:40:27.1 |
HIP 42340 |
11.38 |
| 2026-05-14 00:00 |
08:38:04.46 |
-44:39:40.9 |
HIP 42340 |
10.64 |
| 2026-05-14 12:00 |
08:38:05.44 |
-44:38:54.9 |
HIP 42340 |
9.91 |
| 2026-05-15 00:00 |
08:38:06.46 |
-44:38:09.0 |
HIP 42340 |
9.19 |
| 2026-05-15 12:00 |
08:38:07.52 |
-44:37:23.4 |
HIP 42340 |
8.50 |
| 2026-05-16 00:00 |
08:38:08.62 |
-44:36:38.0 |
HIP 42340 |
7.82 |
| 2026-05-16 12:00 |
08:38:09.76 |
-44:35:52.7 |
HIP 42340 |
7.17 |
| 2026-05-17 00:00 |
08:38:10.95 |
-44:35:07.7 |
HIP 42340 |
6.55 |
| 2026-05-17 12:00 |
08:38:12.17 |
-44:34:22.9 |
HIP 42340 |
5.98 |
| 2026-05-18 00:00 |
08:38:13.44 |
-44:33:38.3 |
HIP 42340 |
5.47 |
| 2026-05-18 12:00 |
08:38:14.75 |
-44:32:54.0 |
HIP 42340 |
5.03 |
| 2026-05-19 00:00 |
08:38:16.10 |
-44:32:09.8 |
HIP 42340 |
4.69 |
| 2026-05-19 12:00 |
08:38:17.50 |
-44:31:25.9 |
HIP 42340 |
4.47 |
| 2026-05-20 00:00 |
08:38:18.93 |
-44:30:42.3 |
HIP 42340 |
4.39 |
| 2026-05-20 12:00 |
08:38:20.40 |
-44:29:58.8 |
HIP 42340 |
4.44 |
| 2026-05-21 00:00 |
08:38:21.91 |
-44:29:15.6 |
HIP 42340 |
4.64 |
| 2026-05-21 12:00 |
08:38:23.47 |
-44:28:32.6 |
HIP 42340 |
4.95 |
| 2026-05-22 00:00 |
08:38:25.06 |
-44:27:49.9 |
HIP 42340 |
5.36 |
| 2026-05-22 12:00 |
08:38:26.69 |
-44:27:07.4 |
HIP 42340 |
5.85 |
| 2026-05-23 00:00 |
08:38:28.37 |
-44:26:25.2 |
HIP 42340 |
6.40 |
| 2026-05-23 12:00 |
08:38:30.08 |
-44:25:43.2 |
HIP 42340 |
6.99 |
| 2026-05-24 00:00 |
08:38:31.83 |
-44:25:01.5 |
HIP 42340 |
7.62 |
| 2026-05-24 12:00 |
08:38:33.62 |
-44:24:20.0 |
HIP 42340 |
8.27 |
| 2026-05-25 00:00 |
08:38:35.44 |
-44:23:38.8 |
HIP 42340 |
8.95 |
| 2026-05-25 12:00 |
08:38:37.31 |
-44:22:57.8 |
HIP 42340 |
9.63 |
| 2026-05-26 00:00 |
08:38:39.21 |
-44:22:17.1 |
HIP 42340 |
10.34 |
| 2026-05-26 12:00 |
08:38:41.15 |
-44:21:36.7 |
HIP 42340 |
11.05 |
| 2026-05-27 00:00 |
08:38:43.13 |
-44:20:56.6 |
HIP 42340 |
11.76 |
| 2026-05-27 12:00 |
08:38:45.15 |
-44:20:16.7 |
HIP 42340 |
12.49 |
| 2026-05-28 00:00 |
08:38:47.20 |
-44:19:37.1 |
HIP 42340 |
13.22 |
| 2026-05-28 12:00 |
08:38:49.29 |
-44:18:57.7 |
HIP 42340 |
13.95 |
| 2026-05-29 00:00 |
08:38:51.41 |
-44:18:18.7 |
HIP 42340 |
14.69 |
| 2026-05-29 12:00 |
08:38:53.58 |
-44:17:39.9 |
HIP 42340 |
15.43 |
| 2026-05-30 00:00 |
08:38:55.77 |
-44:17:01.4 |
HIP 42340 |
16.17 |
| 2026-05-30 12:00 |
08:38:58.01 |
-44:16:23.2 |
HIP 42340 |
16.91 |
| 2026-05-31 00:00 |
08:39:00.28 |
-44:15:45.3 |
HIP 42340 |
17.65 |
| 2026-05-31 12:00 |
08:39:02.58 |
-44:15:07.6 |
HIP 42340 |
18.40 |
| 2026-06-01 00:00 |
08:39:04.92 |
-44:14:30.3 |
HIP 42340 |
19.14 |
| 2026-06-01 12:00 |
08:39:07.30 |
-44:13:53.3 |
HIP 42340 |
19.89 |
| 2026-06-02 00:00 |
08:39:09.71 |
-44:13:16.5 |
HIP 42340 |
20.64 |