| Parameter |
Value |
| Designation |
P/2012 U2 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-12-04T06:27:38.750400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:26Z |
| Obs used |
36 |
| NEO |
- |
| M1 |
12.100 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-11-14.0000000 |
| e |
0.50656873 |
| q (au) |
3.627785 |
| a (au) |
7.352159 |
| i (deg) |
10.534475 |
| Ω (om, deg) |
186.863069 |
| ω (w, deg) |
229.534876 |
| M (ma, deg) |
358.997883 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.078 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.078 |
| n |
6.000 |
| gf |
0.801 |
| gb |
-0.500 |
| k |
0.973 |
| 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 |
17:55:29.10 |
-11:50:26.1 |
HIP 87729 |
14.36 |
| 2026-05-12 12:00 |
17:55:21.73 |
-11:49:58.0 |
HIP 87708 |
13.63 |
| 2026-05-13 00:00 |
17:55:14.28 |
-11:49:30.2 |
HIP 87708 |
12.45 |
| 2026-05-13 12:00 |
17:55:06.74 |
-11:49:02.5 |
HIP 87708 |
11.45 |
| 2026-05-14 00:00 |
17:54:59.12 |
-11:48:35.1 |
HIP 87708 |
10.70 |
| 2026-05-14 12:00 |
17:54:51.42 |
-11:48:07.9 |
HIP 87708 |
10.27 |
| 2026-05-15 00:00 |
17:54:43.65 |
-11:47:40.9 |
HIP 87708 |
10.20 |
| 2026-05-15 12:00 |
17:54:35.79 |
-11:47:14.2 |
HIP 87708 |
10.52 |
| 2026-05-16 00:00 |
17:54:27.85 |
-11:46:47.7 |
HIP 87708 |
11.20 |
| 2026-05-16 12:00 |
17:54:19.84 |
-11:46:21.5 |
HIP 87708 |
12.18 |
| 2026-05-17 00:00 |
17:54:11.75 |
-11:45:55.5 |
HIP 87708 |
13.42 |
| 2026-05-17 12:00 |
17:54:03.58 |
-11:45:29.7 |
HIP 87708 |
14.84 |
| 2026-05-18 00:00 |
17:53:55.34 |
-11:45:04.2 |
HIP 87708 |
16.42 |
| 2026-05-18 12:00 |
17:53:47.03 |
-11:44:38.9 |
HIP 87708 |
18.12 |
| 2026-05-19 00:00 |
17:53:38.64 |
-11:44:13.9 |
HIP 87708 |
19.90 |
| 2026-05-19 12:00 |
17:53:30.18 |
-11:43:49.2 |
HIP 87708 |
21.76 |
| 2026-05-20 00:00 |
17:53:21.65 |
-11:43:24.7 |
HIP 87708 |
23.68 |
| 2026-05-20 12:00 |
17:53:13.05 |
-11:43:00.4 |
HIP 87708 |
25.65 |
| 2026-05-21 00:00 |
17:53:04.39 |
-11:42:36.5 |
HIP 87642 |
27.19 |
| 2026-05-21 12:00 |
17:52:55.65 |
-11:42:12.7 |
HIP 87424 |
26.61 |
| 2026-05-22 00:00 |
17:52:46.85 |
-11:41:49.3 |
HIP 87424 |
25.18 |
| 2026-05-22 12:00 |
17:52:37.99 |
-11:41:26.1 |
HIP 87424 |
23.86 |
| 2026-05-23 00:00 |
17:52:29.05 |
-11:41:03.2 |
HIP 87424 |
22.67 |
| 2026-05-23 12:00 |
17:52:20.06 |
-11:40:40.5 |
HIP 87424 |
21.65 |
| 2026-05-24 00:00 |
17:52:11.01 |
-11:40:18.1 |
HIP 87424 |
20.82 |
| 2026-05-24 12:00 |
17:52:01.89 |
-11:39:56.0 |
HIP 87424 |
20.21 |
| 2026-05-25 00:00 |
17:51:52.71 |
-11:39:34.2 |
HIP 87424 |
19.85 |
| 2026-05-25 12:00 |
17:51:43.48 |
-11:39:12.7 |
HIP 87424 |
19.76 |
| 2026-05-26 00:00 |
17:51:34.18 |
-11:38:51.4 |
HIP 87424 |
19.93 |
| 2026-05-26 12:00 |
17:51:24.83 |
-11:38:30.4 |
HIP 87424 |
20.38 |
| 2026-05-27 00:00 |
17:51:15.43 |
-11:38:09.7 |
HIP 87424 |
21.09 |
| 2026-05-27 12:00 |
17:51:05.97 |
-11:37:49.3 |
HIP 87424 |
22.03 |
| 2026-05-28 00:00 |
17:50:56.45 |
-11:37:29.1 |
HIP 87424 |
23.18 |
| 2026-05-28 12:00 |
17:50:46.88 |
-11:37:09.3 |
HIP 87424 |
24.52 |
| 2026-05-29 00:00 |
17:50:37.27 |
-11:36:49.7 |
HIP 87424 |
26.02 |
| 2026-05-29 12:00 |
17:50:27.60 |
-11:36:30.4 |
HIP 87213 |
25.90 |
| 2026-05-30 00:00 |
17:50:17.88 |
-11:36:11.5 |
HIP 87213 |
23.87 |
| 2026-05-30 12:00 |
17:50:08.11 |
-11:35:52.8 |
HIP 87213 |
21.90 |
| 2026-05-31 00:00 |
17:49:58.30 |
-11:35:34.4 |
HIP 87213 |
20.03 |
| 2026-05-31 12:00 |
17:49:48.43 |
-11:35:16.3 |
HIP 87213 |
18.29 |
| 2026-06-01 00:00 |
17:49:38.53 |
-11:34:58.5 |
HIP 87213 |
16.71 |
| 2026-06-01 12:00 |
17:49:28.58 |
-11:34:41.0 |
HIP 87213 |
15.37 |
| 2026-06-02 00:00 |
17:49:18.58 |
-11:34:23.8 |
HIP 87213 |
14.33 |