| Parameter |
Value |
| Designation |
C/2011 P2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-09-13T12:20:43.287360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:54Z |
| Obs used |
58 |
| NEO |
- |
| M1 |
6.700 |
| K1 |
12.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-02-09.0000000 |
| e |
0.36981923 |
| q (au) |
6.148105 |
| a (au) |
9.756097 |
| i (deg) |
8.989636 |
| Ω (om, deg) |
204.018525 |
| ω (w, deg) |
76.384633 |
| M (ma, deg) |
16.608031 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.498 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.498 |
| n |
6.000 |
| gf |
0.973 |
| 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) |
| 2026-05-12 00:00 |
06:39:14.84 |
+14:41:45.9 |
HIP 31770 |
10.03 |
| 2026-05-12 12:00 |
06:39:22.45 |
+14:41:51.2 |
HIP 31883 |
9.94 |
| 2026-05-13 00:00 |
06:39:30.11 |
+14:41:56.4 |
HIP 31883 |
8.58 |
| 2026-05-13 12:00 |
06:39:37.82 |
+14:42:01.3 |
HIP 31883 |
7.42 |
| 2026-05-14 00:00 |
06:39:45.58 |
+14:42:06.1 |
HIP 31883 |
6.59 |
| 2026-05-14 12:00 |
06:39:53.38 |
+14:42:10.7 |
HIP 31883 |
6.23 |
| 2026-05-15 00:00 |
06:40:01.23 |
+14:42:15.1 |
HIP 31883 |
6.43 |
| 2026-05-15 12:00 |
06:40:09.12 |
+14:42:19.3 |
HIP 31883 |
7.14 |
| 2026-05-16 00:00 |
06:40:17.06 |
+14:42:23.4 |
HIP 31883 |
8.26 |
| 2026-05-16 12:00 |
06:40:25.05 |
+14:42:27.3 |
HIP 31883 |
9.63 |
| 2026-05-17 00:00 |
06:40:33.08 |
+14:42:30.9 |
HIP 31883 |
11.18 |
| 2026-05-17 12:00 |
06:40:41.15 |
+14:42:34.4 |
HIP 32009 |
11.70 |
| 2026-05-18 00:00 |
06:40:49.27 |
+14:42:37.7 |
HIP 32009 |
10.40 |
| 2026-05-18 12:00 |
06:40:57.43 |
+14:42:40.8 |
HIP 32009 |
9.33 |
| 2026-05-19 00:00 |
06:41:05.64 |
+14:42:43.8 |
HIP 32009 |
8.59 |
| 2026-05-19 12:00 |
06:41:13.88 |
+14:42:46.5 |
HIP 32009 |
8.27 |
| 2026-05-20 00:00 |
06:41:22.17 |
+14:42:49.1 |
HIP 32009 |
8.43 |
| 2026-05-20 12:00 |
06:41:30.50 |
+14:42:51.5 |
HIP 32009 |
9.05 |
| 2026-05-21 00:00 |
06:41:38.87 |
+14:42:53.6 |
HIP 32009 |
10.05 |
| 2026-05-21 12:00 |
06:41:47.28 |
+14:42:55.6 |
HIP 32009 |
11.34 |
| 2026-05-22 00:00 |
06:41:55.73 |
+14:42:57.4 |
HIP 32009 |
12.83 |
| 2026-05-22 12:00 |
06:42:04.22 |
+14:42:59.1 |
HIP 32009 |
14.46 |
| 2026-05-23 00:00 |
06:42:12.75 |
+14:43:00.5 |
HIP 32009 |
16.20 |
| 2026-05-23 12:00 |
06:42:21.31 |
+14:43:01.7 |
HIP 32009 |
18.02 |
| 2026-05-24 00:00 |
06:42:29.92 |
+14:43:02.8 |
HIP 32009 |
19.90 |
| 2026-05-24 12:00 |
06:42:38.56 |
+14:43:03.6 |
HIP 32009 |
21.82 |
| 2026-05-25 00:00 |
06:42:47.24 |
+14:43:04.3 |
HIP 32049 |
23.30 |
| 2026-05-25 12:00 |
06:42:55.95 |
+14:43:04.8 |
HIP 32049 |
24.67 |
| 2026-05-26 00:00 |
06:43:04.70 |
+14:43:05.1 |
HIP 32049 |
26.14 |
| 2026-05-26 12:00 |
06:43:13.49 |
+14:43:05.2 |
HIP 32308 |
24.51 |
| 2026-05-27 00:00 |
06:43:22.31 |
+14:43:05.1 |
HIP 32308 |
22.65 |
| 2026-05-27 12:00 |
06:43:31.17 |
+14:43:04.8 |
HIP 32308 |
20.84 |
| 2026-05-28 00:00 |
06:43:40.06 |
+14:43:04.4 |
HIP 32308 |
19.10 |
| 2026-05-28 12:00 |
06:43:48.98 |
+14:43:03.7 |
HIP 32308 |
17.43 |
| 2026-05-29 00:00 |
06:43:57.94 |
+14:43:02.9 |
HIP 32308 |
15.89 |
| 2026-05-29 12:00 |
06:44:06.93 |
+14:43:01.8 |
HIP 32308 |
14.50 |
| 2026-05-30 00:00 |
06:44:15.95 |
+14:43:00.6 |
HIP 32308 |
13.32 |
| 2026-05-30 12:00 |
06:44:25.01 |
+14:42:59.2 |
HIP 32308 |
12.42 |
| 2026-05-31 00:00 |
06:44:34.09 |
+14:42:57.6 |
HIP 32308 |
11.86 |
| 2026-05-31 12:00 |
06:44:43.21 |
+14:42:55.8 |
HIP 32308 |
11.69 |
| 2026-06-01 00:00 |
06:44:52.36 |
+14:42:53.8 |
HIP 32308 |
11.94 |
| 2026-06-01 12:00 |
06:45:01.54 |
+14:42:51.6 |
HIP 32308 |
12.59 |
| 2026-06-02 00:00 |
06:45:10.75 |
+14:42:49.2 |
HIP 32308 |
13.58 |