P/2013 G4 (PANSTARRS)
| Parameter |
Value |
| Designation |
P/2013 G4 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-02-09T16:30:18.377280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:32Z |
| Obs used |
41 |
| NEO |
- |
| M1 |
15.100 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-04-25.0000000 |
| e |
0.41041543 |
| q (au) |
2.613194 |
| a (au) |
4.432263 |
| i (deg) |
5.925606 |
| Ω (om, deg) |
339.772839 |
| ω (w, deg) |
214.390935 |
| M (ma, deg) |
7.849220 |
Magnitude
Scatter + Global Linear
$$
M_a = (19.266 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
19.266 |
| n |
2.000 |
| gf |
0.995 |
| gb |
-0.647 |
| k |
0.800 |
| 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 |
23:19:12.20 |
-02:52:27.2 |
HIP 115037 |
21.00 |
| 2026-02-03 12:00 |
23:19:30.39 |
-02:50:26.1 |
HIP 115037 |
25.97 |
| 2026-02-04 00:00 |
23:19:48.63 |
-02:48:24.5 |
HIP 115294 |
26.53 |
| 2026-02-04 12:00 |
23:20:06.92 |
-02:46:22.6 |
HIP 115294 |
22.06 |
| 2026-02-05 00:00 |
23:20:25.26 |
-02:44:20.4 |
HIP 115294 |
17.85 |
| 2026-02-05 12:00 |
23:20:43.65 |
-02:42:17.7 |
HIP 115294 |
14.18 |
| 2026-02-06 00:00 |
23:21:02.08 |
-02:40:14.7 |
HIP 115294 |
11.55 |
| 2026-02-06 12:00 |
23:21:20.56 |
-02:38:11.3 |
HIP 115294 |
10.81 |
| 2026-02-07 00:00 |
23:21:39.09 |
-02:36:07.6 |
HIP 115294 |
12.31 |
| 2026-02-07 12:00 |
23:21:57.66 |
-02:34:03.5 |
HIP 115294 |
15.42 |
| 2026-02-08 00:00 |
23:22:16.28 |
-02:31:59.0 |
HIP 115294 |
19.39 |
| 2026-02-08 12:00 |
23:22:34.94 |
-02:29:54.2 |
HIP 115294 |
23.80 |
| 2026-02-09 00:00 |
23:22:53.65 |
-02:27:49.1 |
HIP 115294 |
28.45 |
| 2026-02-09 12:00 |
23:23:12.40 |
-02:25:43.6 |
HIP 115294 |
33.26 |
| 2026-02-10 00:00 |
23:23:31.19 |
-02:23:37.7 |
HIP 115595 |
30.75 |
| 2026-02-10 12:00 |
23:23:50.02 |
-02:21:31.6 |
HIP 115595 |
26.09 |
| 2026-02-11 00:00 |
23:24:08.89 |
-02:19:25.1 |
HIP 115595 |
21.63 |
| 2026-02-11 12:00 |
23:24:27.81 |
-02:17:18.3 |
HIP 115595 |
17.57 |
| 2026-02-12 00:00 |
23:24:46.76 |
-02:15:11.1 |
HIP 115595 |
14.23 |
| 2026-02-12 12:00 |
23:25:05.75 |
-02:13:03.7 |
HIP 115595 |
12.25 |
| 2026-02-13 00:00 |
23:25:24.78 |
-02:10:55.9 |
HIP 115595 |
12.32 |
| 2026-02-13 12:00 |
23:25:43.85 |
-02:08:47.8 |
HIP 115595 |
14.42 |
| 2026-02-14 00:00 |
23:26:02.95 |
-02:06:39.4 |
HIP 115595 |
17.86 |
| 2026-02-14 12:00 |
23:26:22.09 |
-02:04:30.7 |
HIP 115595 |
22.02 |
| 2026-02-15 00:00 |
23:26:41.27 |
-02:02:21.7 |
HIP 115595 |
26.58 |
| 2026-02-15 12:00 |
23:27:00.48 |
-02:00:12.5 |
HIP 115595 |
31.36 |
| 2026-02-16 00:00 |
23:27:19.72 |
-01:58:02.9 |
HIP 115845 |
31.31 |
| 2026-02-16 12:00 |
23:27:39.00 |
-01:55:53.1 |
HIP 115945 |
28.27 |
| 2026-02-17 00:00 |
23:27:58.31 |
-01:53:43.0 |
HIP 115945 |
23.02 |
| 2026-02-17 12:00 |
23:28:17.65 |
-01:51:32.6 |
HIP 115945 |
17.80 |
| 2026-02-18 00:00 |
23:28:37.02 |
-01:49:21.9 |
HIP 115945 |
12.63 |
| 2026-02-18 12:00 |
23:28:56.42 |
-01:47:11.0 |
HIP 115945 |
7.65 |
| 2026-02-19 00:00 |
23:29:15.85 |
-01:44:59.8 |
HIP 115945 |
3.72 |
| 2026-02-19 12:00 |
23:29:35.31 |
-01:42:48.4 |
HIP 115945 |
5.10 |
| 2026-02-20 00:00 |
23:29:54.80 |
-01:40:36.7 |
HIP 115945 |
9.76 |
| 2026-02-20 12:00 |
23:30:14.32 |
-01:38:24.8 |
HIP 115945 |
14.89 |
| 2026-02-21 00:00 |
23:30:33.86 |
-01:36:12.7 |
HIP 115945 |
20.15 |
| 2026-02-21 12:00 |
23:30:53.42 |
-01:34:00.3 |
HIP 115945 |
25.45 |
| 2026-02-22 00:00 |
23:31:13.02 |
-01:31:47.7 |
HIP 116146 |
28.87 |
| 2026-02-22 12:00 |
23:31:32.63 |
-01:29:34.9 |
HIP 116146 |
25.21 |
| 2026-02-23 00:00 |
23:31:52.27 |
-01:27:21.8 |
HIP 116146 |
22.25 |
| 2026-02-23 12:00 |
23:32:11.93 |
-01:25:08.5 |
HIP 116146 |
20.31 |
| 2026-02-24 00:00 |
23:32:31.62 |
-01:22:55.1 |
HIP 116146 |
19.70 |