| Parameter |
Value |
| Designation |
P/2011 W1 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-01-22T12:56:24.720000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:58Z |
| Obs used |
171 |
| NEO |
- |
| M1 |
7.300 |
| K1 |
19.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-01-08.0000000 |
| e |
0.28865156 |
| q (au) |
3.312061 |
| a (au) |
4.656031 |
| i (deg) |
3.718613 |
| Ω (om, deg) |
161.883715 |
| ω (w, deg) |
282.472848 |
| M (ma, deg) |
358.573670 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.152 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.152 |
| n |
6.000 |
| gf |
1.000 |
| 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) |
| 2026-09-20 00:00 |
16:21:36.08 |
-17:55:00.8 |
HIP 80083 |
20.80 |
| 2026-09-20 12:00 |
16:21:49.70 |
-17:55:49.3 |
HIP 80083 |
23.56 |
| 2026-09-21 00:00 |
16:22:03.44 |
-17:56:38.0 |
HIP 80083 |
26.48 |
| 2026-09-21 12:00 |
16:22:17.30 |
-17:57:26.9 |
HIP 80083 |
29.52 |
| 2026-09-22 00:00 |
16:22:31.29 |
-17:58:15.9 |
HIP 80378 |
30.47 |
| 2026-09-22 12:00 |
16:22:45.40 |
-17:59:05.0 |
HIP 80378 |
27.92 |
| 2026-09-23 00:00 |
16:22:59.63 |
-17:59:54.2 |
HIP 80378 |
25.55 |
| 2026-09-23 12:00 |
16:23:13.98 |
-18:00:43.5 |
HIP 80378 |
23.45 |
| 2026-09-24 00:00 |
16:23:28.45 |
-18:01:33.0 |
HIP 80378 |
21.70 |
| 2026-09-24 12:00 |
16:23:43.04 |
-18:02:22.6 |
HIP 80378 |
20.41 |
| 2026-09-25 00:00 |
16:23:57.74 |
-18:03:12.2 |
HIP 80378 |
19.67 |
| 2026-09-25 12:00 |
16:24:12.57 |
-18:04:02.0 |
HIP 80378 |
19.58 |
| 2026-09-26 00:00 |
16:24:27.51 |
-18:04:51.9 |
HIP 80378 |
20.15 |
| 2026-09-26 12:00 |
16:24:42.56 |
-18:05:41.9 |
HIP 80378 |
21.35 |
| 2026-09-27 00:00 |
16:24:57.74 |
-18:06:31.9 |
HIP 80378 |
23.09 |
| 2026-09-27 12:00 |
16:25:13.02 |
-18:07:22.1 |
HIP 80378 |
25.26 |
| 2026-09-28 00:00 |
16:25:28.42 |
-18:08:12.3 |
HIP 80378 |
27.79 |
| 2026-09-28 12:00 |
16:25:43.94 |
-18:09:02.6 |
HIP 80569 |
25.97 |
| 2026-09-29 00:00 |
16:25:59.56 |
-18:09:53.0 |
HIP 80569 |
22.84 |
| 2026-09-29 12:00 |
16:26:15.30 |
-18:10:43.5 |
HIP 80569 |
19.92 |
| 2026-09-30 00:00 |
16:26:31.15 |
-18:11:34.1 |
HIP 80569 |
17.36 |
| 2026-09-30 12:00 |
16:26:47.12 |
-18:12:24.7 |
HIP 80569 |
15.34 |
| 2026-10-01 00:00 |
16:27:03.19 |
-18:13:15.3 |
HIP 80569 |
14.12 |
| 2026-10-01 12:00 |
16:27:19.37 |
-18:14:06.1 |
HIP 80569 |
13.94 |
| 2026-10-02 00:00 |
16:27:35.66 |
-18:14:56.8 |
HIP 80569 |
14.84 |
| 2026-10-02 12:00 |
16:27:52.06 |
-18:15:47.7 |
HIP 80569 |
16.68 |
| 2026-10-03 00:00 |
16:28:08.56 |
-18:16:38.6 |
HIP 80569 |
19.20 |
| 2026-10-03 12:00 |
16:28:25.18 |
-18:17:29.5 |
HIP 80712 |
19.02 |
| 2026-10-04 00:00 |
16:28:41.90 |
-18:18:20.4 |
HIP 80712 |
19.26 |
| 2026-10-04 12:00 |
16:28:58.72 |
-18:19:11.4 |
HIP 80712 |
20.34 |
| 2026-10-05 00:00 |
16:29:15.66 |
-18:20:02.5 |
HIP 80784 |
21.77 |
| 2026-10-05 12:00 |
16:29:32.69 |
-18:20:53.5 |
HIP 80784 |
20.08 |
| 2026-10-06 00:00 |
16:29:49.83 |
-18:21:44.6 |
HIP 80784 |
19.13 |
| 2026-10-06 12:00 |
16:30:07.08 |
-18:22:35.7 |
HIP 80784 |
19.08 |
| 2026-10-07 00:00 |
16:30:24.42 |
-18:23:26.8 |
HIP 80889 |
16.56 |
| 2026-10-07 12:00 |
16:30:41.87 |
-18:24:17.9 |
HIP 80889 |
13.87 |
| 2026-10-08 00:00 |
16:30:59.42 |
-18:25:09.1 |
HIP 80889 |
12.10 |
| 2026-10-08 12:00 |
16:31:17.07 |
-18:26:00.2 |
HIP 80889 |
11.69 |
| 2026-10-09 00:00 |
16:31:34.82 |
-18:26:51.3 |
HIP 80889 |
12.80 |
| 2026-10-09 12:00 |
16:31:52.67 |
-18:27:42.5 |
HIP 80889 |
15.11 |
| 2026-10-10 00:00 |
16:32:10.62 |
-18:28:33.6 |
HIP 80889 |
18.18 |
| 2026-10-10 12:00 |
16:32:28.67 |
-18:29:24.7 |
HIP 80889 |
21.72 |
| 2026-10-11 00:00 |
16:32:46.81 |
-18:30:15.8 |
HIP 80889 |
25.53 |