P/2015 P4 (PANSTARRS)
| Parameter |
Value |
| Designation |
P/2015 P4 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2016-01-19T00:45:47.321280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:13Z |
| Obs used |
80 |
| NEO |
- |
| M1 |
6.500 |
| K1 |
28.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-09-21.0000000 |
| e |
0.58423891 |
| q (au) |
2.525162 |
| a (au) |
6.073589 |
| i (deg) |
8.713757 |
| Ω (om, deg) |
104.746924 |
| ω (w, deg) |
280.816811 |
| M (ma, deg) |
352.096266 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.240 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.240 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-02-03 00:00 |
15:32:24.81 |
-11:38:13.9 |
HIP 76020 |
26.23 |
| 2026-02-03 12:00 |
15:32:30.66 |
-11:38:13.7 |
HIP 76020 |
26.88 |
| 2026-02-04 00:00 |
15:32:36.42 |
-11:38:13.0 |
HIP 76020 |
27.58 |
| 2026-02-04 12:00 |
15:32:42.07 |
-11:38:11.9 |
HIP 76020 |
28.30 |
| 2026-02-05 00:00 |
15:32:47.61 |
-11:38:10.3 |
HIP 76020 |
29.06 |
| 2026-02-05 12:00 |
15:32:53.06 |
-11:38:08.3 |
HIP 76258 |
28.53 |
| 2026-02-06 00:00 |
15:32:58.40 |
-11:38:05.8 |
HIP 76258 |
27.39 |
| 2026-02-06 12:00 |
15:33:03.63 |
-11:38:02.9 |
HIP 76258 |
26.29 |
| 2026-02-07 00:00 |
15:33:08.76 |
-11:37:59.4 |
HIP 76258 |
25.24 |
| 2026-02-07 12:00 |
15:33:13.78 |
-11:37:55.5 |
HIP 76258 |
24.23 |
| 2026-02-08 00:00 |
15:33:18.70 |
-11:37:51.2 |
HIP 76258 |
23.27 |
| 2026-02-08 12:00 |
15:33:23.51 |
-11:37:46.4 |
HIP 76258 |
22.36 |
| 2026-02-09 00:00 |
15:33:28.21 |
-11:37:41.1 |
HIP 76258 |
21.50 |
| 2026-02-09 12:00 |
15:33:32.81 |
-11:37:35.4 |
HIP 76258 |
20.69 |
| 2026-02-10 00:00 |
15:33:37.29 |
-11:37:29.2 |
HIP 76258 |
19.94 |
| 2026-02-10 12:00 |
15:33:41.67 |
-11:37:22.5 |
HIP 76258 |
19.25 |
| 2026-02-11 00:00 |
15:33:45.94 |
-11:37:15.4 |
HIP 76258 |
18.61 |
| 2026-02-11 12:00 |
15:33:50.10 |
-11:37:07.9 |
HIP 76258 |
18.04 |
| 2026-02-12 00:00 |
15:33:54.14 |
-11:36:59.8 |
HIP 76258 |
17.54 |
| 2026-02-12 12:00 |
15:33:58.08 |
-11:36:51.3 |
HIP 76258 |
17.10 |
| 2026-02-13 00:00 |
15:34:01.91 |
-11:36:42.4 |
HIP 76258 |
16.72 |
| 2026-02-13 12:00 |
15:34:05.62 |
-11:36:33.0 |
HIP 76258 |
16.41 |
| 2026-02-14 00:00 |
15:34:09.22 |
-11:36:23.1 |
HIP 76258 |
16.17 |
| 2026-02-14 12:00 |
15:34:12.71 |
-11:36:12.8 |
HIP 76258 |
15.98 |
| 2026-02-15 00:00 |
15:34:16.09 |
-11:36:02.0 |
HIP 76258 |
15.87 |
| 2026-02-15 12:00 |
15:34:19.36 |
-11:35:50.8 |
HIP 76258 |
15.81 |
| 2026-02-16 00:00 |
15:34:22.51 |
-11:35:39.1 |
HIP 76322 |
15.69 |
| 2026-02-16 12:00 |
15:34:25.54 |
-11:35:27.0 |
HIP 76322 |
15.06 |
| 2026-02-17 00:00 |
15:34:28.47 |
-11:35:14.4 |
HIP 76322 |
14.48 |
| 2026-02-17 12:00 |
15:34:31.27 |
-11:35:01.4 |
HIP 76322 |
13.94 |
| 2026-02-18 00:00 |
15:34:33.97 |
-11:34:47.9 |
HIP 76322 |
13.44 |
| 2026-02-18 12:00 |
15:34:36.54 |
-11:34:34.0 |
HIP 76322 |
13.00 |
| 2026-02-19 00:00 |
15:34:39.00 |
-11:34:19.7 |
HIP 76322 |
12.60 |
| 2026-02-19 12:00 |
15:34:41.35 |
-11:34:04.9 |
HIP 76322 |
12.25 |
| 2026-02-20 00:00 |
15:34:43.58 |
-11:33:49.6 |
HIP 76322 |
11.95 |
| 2026-02-20 12:00 |
15:34:45.69 |
-11:33:33.9 |
HIP 76322 |
11.70 |
| 2026-02-21 00:00 |
15:34:47.69 |
-11:33:17.8 |
HIP 76322 |
11.50 |
| 2026-02-21 12:00 |
15:34:49.57 |
-11:33:01.3 |
HIP 76322 |
11.35 |
| 2026-02-22 00:00 |
15:34:51.34 |
-11:32:44.3 |
HIP 76322 |
11.25 |
| 2026-02-22 12:00 |
15:34:52.98 |
-11:32:26.8 |
HIP 76322 |
11.20 |
| 2026-02-23 00:00 |
15:34:54.51 |
-11:32:09.0 |
HIP 76322 |
11.19 |
| 2026-02-23 12:00 |
15:34:55.92 |
-11:31:50.7 |
HIP 76322 |
11.23 |
| 2026-02-24 00:00 |
15:34:57.22 |
-11:31:32.0 |
HIP 76322 |
11.30 |