| Parameter |
Value |
| Designation |
C/2012 S4 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-06-28T00:33:42.019200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:22Z |
| Obs used |
924 |
| NEO |
- |
| M1 |
9.400 |
| K1 |
8.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-04-24.0000000 |
| e |
0.99998199 |
| q (au) |
4.348728 |
| a (au) |
241497.706412 |
| i (deg) |
126.541334 |
| Ω (om, deg) |
173.103524 |
| ω (w, deg) |
163.615485 |
| M (ma, deg) |
359.999999 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.722 + 4.989\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.722 |
| n |
4.989 |
| gf |
0.979 |
| gb |
-0.511 |
| k |
0.800 |
| δ90 |
9.878 |
| 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) |
| 2026-07-29 00:00 |
12:51:21.41 |
-56:48:41.7 |
HIP 62862 |
14.13 |
| 2026-07-29 12:00 |
12:51:23.85 |
-56:47:55.5 |
HIP 62862 |
13.79 |
| 2026-07-30 00:00 |
12:51:26.34 |
-56:47:09.5 |
HIP 62862 |
13.49 |
| 2026-07-30 12:00 |
12:51:28.89 |
-56:46:23.8 |
HIP 62862 |
13.22 |
| 2026-07-31 00:00 |
12:51:31.48 |
-56:45:38.4 |
HIP 62809 |
12.54 |
| 2026-07-31 12:00 |
12:51:34.13 |
-56:44:53.4 |
HIP 62809 |
11.70 |
| 2026-08-01 00:00 |
12:51:36.83 |
-56:44:08.6 |
HIP 62809 |
10.87 |
| 2026-08-01 12:00 |
12:51:39.58 |
-56:43:24.2 |
HIP 62809 |
10.04 |
| 2026-08-02 00:00 |
12:51:42.39 |
-56:42:40.1 |
HIP 62809 |
9.21 |
| 2026-08-02 12:00 |
12:51:45.24 |
-56:41:56.3 |
HIP 62809 |
8.38 |
| 2026-08-03 00:00 |
12:51:48.14 |
-56:41:12.8 |
HIP 62809 |
7.55 |
| 2026-08-03 12:00 |
12:51:51.10 |
-56:40:29.7 |
HIP 62809 |
6.73 |
| 2026-08-04 00:00 |
12:51:54.10 |
-56:39:46.8 |
HIP 62809 |
5.91 |
| 2026-08-04 12:00 |
12:51:57.16 |
-56:39:04.3 |
HIP 62809 |
5.09 |
| 2026-08-05 00:00 |
12:52:00.26 |
-56:38:22.1 |
HIP 62809 |
4.27 |
| 2026-08-05 12:00 |
12:52:03.41 |
-56:37:40.3 |
HIP 62809 |
3.46 |
| 2026-08-06 00:00 |
12:52:06.62 |
-56:36:58.8 |
HIP 62809 |
2.67 |
| 2026-08-06 12:00 |
12:52:09.87 |
-56:36:17.6 |
HIP 62809 |
1.89 |
| 2026-08-07 00:00 |
12:52:13.17 |
-56:35:36.7 |
HIP 62809 |
1.18 |
| 2026-08-07 12:00 |
12:52:16.52 |
-56:34:56.2 |
HIP 62809 |
0.76 |
| 2026-08-08 00:00 |
12:52:19.91 |
-56:34:16.1 |
HIP 62809 |
1.05 |
| 2026-08-08 12:00 |
12:52:23.36 |
-56:33:36.3 |
HIP 62809 |
1.73 |
| 2026-08-09 00:00 |
12:52:26.85 |
-56:32:56.8 |
HIP 62809 |
2.49 |
| 2026-08-09 12:00 |
12:52:30.39 |
-56:32:17.7 |
HIP 62809 |
3.28 |
| 2026-08-10 00:00 |
12:52:33.97 |
-56:31:38.9 |
HIP 62809 |
4.08 |
| 2026-08-10 12:00 |
12:52:37.61 |
-56:31:00.5 |
HIP 62809 |
4.88 |
| 2026-08-11 00:00 |
12:52:41.28 |
-56:30:22.4 |
HIP 62809 |
5.69 |
| 2026-08-11 12:00 |
12:52:45.01 |
-56:29:44.7 |
HIP 62809 |
6.50 |
| 2026-08-12 00:00 |
12:52:48.78 |
-56:29:07.3 |
HIP 62809 |
7.31 |
| 2026-08-12 12:00 |
12:52:52.59 |
-56:28:30.4 |
HIP 62809 |
8.12 |
| 2026-08-13 00:00 |
12:52:56.45 |
-56:27:53.7 |
HIP 62809 |
8.93 |
| 2026-08-13 12:00 |
12:53:00.36 |
-56:27:17.5 |
HIP 62809 |
9.74 |
| 2026-08-14 00:00 |
12:53:04.31 |
-56:26:41.6 |
HIP 62809 |
10.55 |
| 2026-08-14 12:00 |
12:53:08.30 |
-56:26:06.0 |
HIP 62809 |
11.36 |
| 2026-08-15 00:00 |
12:53:12.34 |
-56:25:30.9 |
HIP 62809 |
12.17 |
| 2026-08-15 12:00 |
12:53:16.42 |
-56:24:56.1 |
HIP 62809 |
12.98 |
| 2026-08-16 00:00 |
12:53:20.54 |
-56:24:21.7 |
HIP 62883 |
12.75 |
| 2026-08-16 12:00 |
12:53:24.71 |
-56:23:47.6 |
HIP 62883 |
12.23 |
| 2026-08-17 00:00 |
12:53:28.91 |
-56:23:14.0 |
HIP 62883 |
11.74 |
| 2026-08-17 12:00 |
12:53:33.16 |
-56:22:40.7 |
HIP 62883 |
11.31 |
| 2026-08-18 00:00 |
12:53:37.45 |
-56:22:07.8 |
HIP 62883 |
10.92 |
| 2026-08-18 12:00 |
12:53:41.78 |
-56:21:35.3 |
HIP 62883 |
10.58 |
| 2026-08-19 00:00 |
12:53:46.15 |
-56:21:03.1 |
HIP 62883 |
10.31 |