| Parameter |
Value |
| Designation |
C/2015 GX (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-08-26T15:53:06.691200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:09Z |
| Obs used |
318 |
| NEO |
- |
| M1 |
14.200 |
| K1 |
7.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-09-13.0000000 |
| e |
0.87819882 |
| q (au) |
1.971753 |
| a (au) |
16.188294 |
| i (deg) |
90.254528 |
| Ω (om, deg) |
235.515503 |
| ω (w, deg) |
108.957919 |
| M (ma, deg) |
0.262364 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.937 + 5.219\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.937 |
| n |
5.219 |
| gf |
0.999 |
| gb |
-0.627 |
| 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) |
| 2026-09-20 00:00 |
06:15:13.80 |
-65:01:42.7 |
HIP 29995 |
23.41 |
| 2026-09-20 12:00 |
06:15:15.78 |
-65:03:13.6 |
HIP 29995 |
22.91 |
| 2026-09-21 00:00 |
06:15:17.66 |
-65:04:44.6 |
HIP 29995 |
22.52 |
| 2026-09-21 12:00 |
06:15:19.42 |
-65:06:15.7 |
HIP 29995 |
22.23 |
| 2026-09-22 00:00 |
06:15:21.07 |
-65:07:46.8 |
HIP 29995 |
22.06 |
| 2026-09-22 12:00 |
06:15:22.61 |
-65:09:17.9 |
HIP 29995 |
22.01 |
| 2026-09-23 00:00 |
06:15:24.04 |
-65:10:49.1 |
HIP 29995 |
22.07 |
| 2026-09-23 12:00 |
06:15:25.36 |
-65:12:20.4 |
HIP 29995 |
22.26 |
| 2026-09-24 00:00 |
06:15:26.56 |
-65:13:51.6 |
HIP 29995 |
22.55 |
| 2026-09-24 12:00 |
06:15:27.65 |
-65:15:22.9 |
HIP 29995 |
22.96 |
| 2026-09-25 00:00 |
06:15:28.62 |
-65:16:54.2 |
HIP 29995 |
23.47 |
| 2026-09-25 12:00 |
06:15:29.48 |
-65:18:25.5 |
HIP 29995 |
24.07 |
| 2026-09-26 00:00 |
06:15:30.23 |
-65:19:56.8 |
HIP 29444 |
23.71 |
| 2026-09-26 12:00 |
06:15:30.86 |
-65:21:28.2 |
HIP 29444 |
23.02 |
| 2026-09-27 00:00 |
06:15:31.38 |
-65:22:59.5 |
HIP 29444 |
22.40 |
| 2026-09-27 12:00 |
06:15:31.78 |
-65:24:30.8 |
HIP 29444 |
21.86 |
| 2026-09-28 00:00 |
06:15:32.07 |
-65:26:02.1 |
HIP 29444 |
21.40 |
| 2026-09-28 12:00 |
06:15:32.24 |
-65:27:33.3 |
HIP 29444 |
21.03 |
| 2026-09-29 00:00 |
06:15:32.29 |
-65:29:04.6 |
HIP 29444 |
20.76 |
| 2026-09-29 12:00 |
06:15:32.23 |
-65:30:35.8 |
HIP 29444 |
20.58 |
| 2026-09-30 00:00 |
06:15:32.05 |
-65:32:07.0 |
HIP 29444 |
20.50 |
| 2026-09-30 12:00 |
06:15:31.75 |
-65:33:38.1 |
HIP 29444 |
20.52 |
| 2026-10-01 00:00 |
06:15:31.34 |
-65:35:09.2 |
HIP 29444 |
20.64 |
| 2026-10-01 12:00 |
06:15:30.80 |
-65:36:40.2 |
HIP 29444 |
20.85 |
| 2026-10-02 00:00 |
06:15:30.15 |
-65:38:11.1 |
HIP 29444 |
21.17 |
| 2026-10-02 12:00 |
06:15:29.38 |
-65:39:42.0 |
HIP 29444 |
21.57 |
| 2026-10-03 00:00 |
06:15:28.49 |
-65:41:12.8 |
HIP 29444 |
22.06 |
| 2026-10-03 12:00 |
06:15:27.48 |
-65:42:43.5 |
HIP 29444 |
22.63 |
| 2026-10-04 00:00 |
06:15:26.35 |
-65:44:14.2 |
HIP 29444 |
23.27 |
| 2026-10-04 12:00 |
06:15:25.10 |
-65:45:44.7 |
HIP 29444 |
23.98 |
| 2026-10-05 00:00 |
06:15:23.73 |
-65:47:15.1 |
HIP 29444 |
24.75 |
| 2026-10-05 12:00 |
06:15:22.23 |
-65:48:45.5 |
HIP 29574 |
23.45 |
| 2026-10-06 00:00 |
06:15:20.62 |
-65:50:15.7 |
HIP 29574 |
22.00 |
| 2026-10-06 12:00 |
06:15:18.89 |
-65:51:45.8 |
HIP 29574 |
20.55 |
| 2026-10-07 00:00 |
06:15:17.03 |
-65:53:15.7 |
HIP 29574 |
19.12 |
| 2026-10-07 12:00 |
06:15:15.05 |
-65:54:45.6 |
HIP 29574 |
17.69 |
| 2026-10-08 00:00 |
06:15:12.95 |
-65:56:15.2 |
HIP 29574 |
16.27 |
| 2026-10-08 12:00 |
06:15:10.73 |
-65:57:44.8 |
HIP 29574 |
14.87 |
| 2026-10-09 00:00 |
06:15:08.38 |
-65:59:14.2 |
HIP 29574 |
13.48 |
| 2026-10-09 12:00 |
06:15:05.91 |
-66:00:43.4 |
HIP 29574 |
12.12 |
| 2026-10-10 00:00 |
06:15:03.32 |
-66:02:12.4 |
HIP 29574 |
10.80 |
| 2026-10-10 12:00 |
06:15:00.61 |
-66:03:41.3 |
HIP 29574 |
9.52 |
| 2026-10-11 00:00 |
06:14:57.77 |
-66:05:10.0 |
HIP 29574 |
8.31 |