| Parameter |
Value |
| Designation |
C/2014 S2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-12-09T19:08:29.909760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:00Z |
| Obs used |
2941 |
| NEO |
- |
| M1 |
6.000 |
| K1 |
13.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2016-01-10.0000000 |
| e |
0.98762625 |
| q (au) |
2.100643 |
| a (au) |
169.766118 |
| i (deg) |
64.670381 |
| Ω (om, deg) |
8.122248 |
| ω (w, deg) |
87.806610 |
| M (ma, deg) |
0.013903 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.333 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.333 |
| n |
6.000 |
| gf |
0.802 |
| gb |
-0.500 |
| k |
0.936 |
| δ90 |
1.000 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2014-04-28 |
2015-04-25 |
-24.2188 |
+17.742 |
| 2015-04-25 |
2015-12-09 |
+33.0276 |
-11.675 |
| 2015-12-09 |
2017-04-01 |
+2.8013 |
-2.446 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
12:29:25.92 |
-56:39:57.1 |
HIP 60969 |
9.31 |
| 2026-07-29 12:00 |
12:29:29.71 |
-56:39:21.3 |
HIP 60969 |
8.55 |
| 2026-07-30 00:00 |
12:29:33.56 |
-56:38:45.8 |
HIP 60969 |
7.80 |
| 2026-07-30 12:00 |
12:29:37.46 |
-56:38:10.7 |
HIP 60969 |
7.07 |
| 2026-07-31 00:00 |
12:29:41.42 |
-56:37:36.0 |
HIP 60969 |
6.35 |
| 2026-07-31 12:00 |
12:29:45.42 |
-56:37:01.6 |
HIP 60969 |
5.66 |
| 2026-08-01 00:00 |
12:29:49.49 |
-56:36:27.7 |
HIP 60969 |
5.01 |
| 2026-08-01 12:00 |
12:29:53.60 |
-56:35:54.1 |
HIP 60969 |
4.40 |
| 2026-08-02 00:00 |
12:29:57.77 |
-56:35:20.8 |
HIP 60969 |
3.88 |
| 2026-08-02 12:00 |
12:30:01.98 |
-56:34:48.0 |
HIP 60969 |
3.47 |
| 2026-08-03 00:00 |
12:30:06.25 |
-56:34:15.5 |
HIP 60969 |
3.22 |
| 2026-08-03 12:00 |
12:30:10.57 |
-56:33:43.4 |
HIP 60969 |
3.17 |
| 2026-08-04 00:00 |
12:30:14.94 |
-56:33:11.7 |
HIP 60969 |
3.33 |
| 2026-08-04 12:00 |
12:30:19.36 |
-56:32:40.3 |
HIP 60969 |
3.66 |
| 2026-08-05 00:00 |
12:30:23.84 |
-56:32:09.4 |
HIP 60969 |
4.14 |
| 2026-08-05 12:00 |
12:30:28.36 |
-56:31:38.9 |
HIP 60969 |
4.71 |
| 2026-08-06 00:00 |
12:30:32.93 |
-56:31:08.7 |
HIP 60969 |
5.35 |
| 2026-08-06 12:00 |
12:30:37.55 |
-56:30:38.9 |
HIP 60969 |
6.04 |
| 2026-08-07 00:00 |
12:30:42.22 |
-56:30:09.6 |
HIP 60969 |
6.76 |
| 2026-08-07 12:00 |
12:30:46.94 |
-56:29:40.6 |
HIP 60969 |
7.50 |
| 2026-08-08 00:00 |
12:30:51.71 |
-56:29:12.0 |
HIP 60969 |
8.26 |
| 2026-08-08 12:00 |
12:30:56.53 |
-56:28:43.9 |
HIP 60969 |
9.03 |
| 2026-08-09 00:00 |
12:31:01.39 |
-56:28:16.1 |
HIP 60969 |
9.82 |
| 2026-08-09 12:00 |
12:31:06.30 |
-56:27:48.8 |
HIP 61188 |
9.72 |
| 2026-08-10 00:00 |
12:31:11.26 |
-56:27:21.8 |
HIP 61188 |
9.06 |
| 2026-08-10 12:00 |
12:31:16.27 |
-56:26:55.3 |
HIP 61188 |
8.42 |
| 2026-08-11 00:00 |
12:31:21.32 |
-56:26:29.2 |
HIP 61188 |
7.81 |
| 2026-08-11 12:00 |
12:31:26.42 |
-56:26:03.5 |
HIP 61188 |
7.23 |
| 2026-08-12 00:00 |
12:31:31.56 |
-56:25:38.2 |
HIP 61188 |
6.69 |
| 2026-08-12 12:00 |
12:31:36.75 |
-56:25:13.3 |
HIP 61188 |
6.21 |
| 2026-08-13 00:00 |
12:31:41.98 |
-56:24:48.9 |
HIP 61188 |
5.79 |
| 2026-08-13 12:00 |
12:31:47.26 |
-56:24:24.9 |
HIP 61188 |
5.46 |
| 2026-08-14 00:00 |
12:31:52.59 |
-56:24:01.3 |
HIP 61188 |
5.24 |
| 2026-08-14 12:00 |
12:31:57.95 |
-56:23:38.1 |
HIP 61188 |
5.13 |
| 2026-08-15 00:00 |
12:32:03.36 |
-56:23:15.3 |
HIP 61188 |
5.15 |
| 2026-08-15 12:00 |
12:32:08.81 |
-56:22:53.0 |
HIP 61188 |
5.30 |
| 2026-08-16 00:00 |
12:32:14.31 |
-56:22:31.1 |
HIP 61166 |
5.50 |
| 2026-08-16 12:00 |
12:32:19.85 |
-56:22:09.7 |
HIP 61221 |
4.96 |
| 2026-08-17 00:00 |
12:32:25.43 |
-56:21:48.6 |
HIP 61221 |
4.19 |
| 2026-08-17 12:00 |
12:32:31.05 |
-56:21:28.0 |
HIP 61221 |
3.47 |
| 2026-08-18 00:00 |
12:32:36.71 |
-56:21:07.9 |
HIP 61221 |
2.81 |
| 2026-08-18 12:00 |
12:32:42.41 |
-56:20:48.2 |
HIP 61221 |
2.31 |
| 2026-08-19 00:00 |
12:32:48.15 |
-56:20:28.9 |
HIP 61221 |
2.05 |