| 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) |
| 2026-03-26 00:00 |
16:54:52.44 |
-18:35:27.7 |
HIP 82674 |
15.23 |
| 2026-03-26 12:00 |
16:54:52.63 |
-18:35:07.2 |
HIP 82674 |
15.47 |
| 2026-03-27 00:00 |
16:54:52.63 |
-18:34:46.3 |
HIP 82674 |
15.69 |
| 2026-03-27 12:00 |
16:54:52.45 |
-18:34:25.2 |
HIP 82674 |
15.88 |
| 2026-03-28 00:00 |
16:54:52.10 |
-18:34:03.8 |
HIP 82674 |
16.04 |
| 2026-03-28 12:00 |
16:54:51.56 |
-18:33:42.1 |
HIP 82674 |
16.19 |
| 2026-03-29 00:00 |
16:54:50.83 |
-18:33:20.2 |
HIP 82674 |
16.31 |
| 2026-03-29 12:00 |
16:54:49.93 |
-18:32:58.0 |
HIP 82674 |
16.42 |
| 2026-03-30 00:00 |
16:54:48.84 |
-18:32:35.5 |
HIP 82674 |
16.51 |
| 2026-03-30 12:00 |
16:54:47.57 |
-18:32:12.8 |
HIP 82674 |
16.59 |
| 2026-03-31 00:00 |
16:54:46.12 |
-18:31:49.8 |
HIP 82674 |
16.65 |
| 2026-03-31 12:00 |
16:54:44.49 |
-18:31:26.5 |
HIP 82674 |
16.71 |
| 2026-04-01 00:00 |
16:54:42.68 |
-18:31:03.0 |
HIP 82674 |
16.76 |
| 2026-04-01 12:00 |
16:54:40.68 |
-18:30:39.2 |
HIP 82674 |
16.82 |
| 2026-04-02 00:00 |
16:54:38.51 |
-18:30:15.2 |
HIP 82674 |
16.87 |
| 2026-04-02 12:00 |
16:54:36.15 |
-18:29:50.9 |
HIP 82674 |
16.94 |
| 2026-04-03 00:00 |
16:54:33.62 |
-18:29:26.4 |
HIP 82674 |
17.01 |
| 2026-04-03 12:00 |
16:54:30.90 |
-18:29:01.6 |
HIP 82674 |
17.11 |
| 2026-04-04 00:00 |
16:54:28.00 |
-18:28:36.6 |
HIP 82674 |
17.22 |
| 2026-04-04 12:00 |
16:54:24.92 |
-18:28:11.3 |
HIP 82674 |
17.36 |
| 2026-04-05 00:00 |
16:54:21.66 |
-18:27:45.8 |
HIP 82674 |
17.53 |
| 2026-04-05 12:00 |
16:54:18.22 |
-18:27:20.1 |
HIP 82674 |
17.74 |
| 2026-04-06 00:00 |
16:54:14.60 |
-18:26:54.1 |
HIP 82674 |
17.99 |
| 2026-04-06 12:00 |
16:54:10.80 |
-18:26:27.8 |
HIP 82674 |
18.29 |
| 2026-04-07 00:00 |
16:54:06.83 |
-18:26:01.3 |
HIP 82674 |
18.63 |
| 2026-04-07 12:00 |
16:54:02.67 |
-18:25:34.6 |
HIP 82674 |
19.03 |
| 2026-04-08 00:00 |
16:53:58.33 |
-18:25:07.7 |
HIP 82674 |
19.48 |
| 2026-04-08 12:00 |
16:53:53.82 |
-18:24:40.5 |
HIP 82674 |
20.00 |
| 2026-04-09 00:00 |
16:53:49.13 |
-18:24:13.1 |
HIP 82674 |
20.58 |
| 2026-04-09 12:00 |
16:53:44.26 |
-18:23:45.4 |
HIP 82674 |
21.22 |
| 2026-04-10 00:00 |
16:53:39.21 |
-18:23:17.6 |
HIP 82674 |
21.93 |
| 2026-04-10 12:00 |
16:53:33.99 |
-18:22:49.5 |
HIP 82674 |
22.70 |
| 2026-04-11 00:00 |
16:53:28.59 |
-18:22:21.2 |
HIP 82674 |
23.54 |
| 2026-04-11 12:00 |
16:53:23.02 |
-18:21:52.6 |
HIP 82674 |
24.44 |
| 2026-04-12 00:00 |
16:53:17.27 |
-18:21:23.9 |
HIP 82665 |
24.68 |
| 2026-04-12 12:00 |
16:53:11.35 |
-18:20:54.9 |
HIP 82665 |
24.82 |
| 2026-04-13 00:00 |
16:53:05.25 |
-18:20:25.7 |
HIP 82665 |
25.06 |
| 2026-04-13 12:00 |
16:52:58.98 |
-18:19:56.3 |
HIP 82665 |
25.41 |
| 2026-04-14 00:00 |
16:52:52.53 |
-18:19:26.7 |
HIP 82665 |
25.87 |
| 2026-04-14 12:00 |
16:52:45.92 |
-18:18:56.9 |
HIP 82665 |
26.45 |
| 2026-04-15 00:00 |
16:52:39.13 |
-18:18:26.9 |
HIP 82665 |
27.13 |
| 2026-04-15 12:00 |
16:52:32.17 |
-18:17:56.7 |
HIP 82665 |
27.93 |
| 2026-04-16 00:00 |
16:52:25.04 |
-18:17:26.3 |
HIP 82665 |
28.85 |