| Parameter |
Value |
| Designation |
C/2017 G3 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-04-15T00:45:00.587520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:33Z |
| Obs used |
155 |
| NEO |
- |
| M1 |
14.500 |
| K1 |
9.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-05-26.0000000 |
| e |
0.99105792 |
| q (au) |
2.590476 |
| a (au) |
289.694902 |
| i (deg) |
159.051707 |
| Ω (om, deg) |
279.473026 |
| ω (w, deg) |
73.096573 |
| M (ma, deg) |
0.008189 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.149 + 3.830\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.149 |
| n |
3.830 |
| gf |
0.994 |
| gb |
-0.606 |
| k |
0.905 |
| δ90 |
7.745 |
| 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) |
| 2026-06-01 00:00 |
04:30:53.02 |
+10:47:12.1 |
HIP 21066 |
2.32 |
| 2026-06-01 12:00 |
04:30:57.64 |
+10:47:19.5 |
HIP 21066 |
2.22 |
| 2026-06-02 00:00 |
04:31:02.25 |
+10:47:26.7 |
HIP 21066 |
2.66 |
| 2026-06-02 12:00 |
04:31:06.85 |
+10:47:33.8 |
HIP 21066 |
3.43 |
| 2026-06-03 00:00 |
04:31:11.46 |
+10:47:40.8 |
HIP 21066 |
4.36 |
| 2026-06-03 12:00 |
04:31:16.06 |
+10:47:47.6 |
HIP 21066 |
5.37 |
| 2026-06-04 00:00 |
04:31:20.66 |
+10:47:54.4 |
HIP 21066 |
6.43 |
| 2026-06-04 12:00 |
04:31:25.26 |
+10:48:00.9 |
HIP 21066 |
7.50 |
| 2026-06-05 00:00 |
04:31:29.86 |
+10:48:07.4 |
HIP 21066 |
8.59 |
| 2026-06-05 12:00 |
04:31:34.45 |
+10:48:13.7 |
HIP 21066 |
9.69 |
| 2026-06-06 00:00 |
04:31:39.03 |
+10:48:19.9 |
HIP 21066 |
10.79 |
| 2026-06-06 12:00 |
04:31:43.61 |
+10:48:25.9 |
HIP 21066 |
11.89 |
| 2026-06-07 00:00 |
04:31:48.19 |
+10:48:31.8 |
HIP 21066 |
13.00 |
| 2026-06-07 12:00 |
04:31:52.76 |
+10:48:37.6 |
HIP 21176 |
12.78 |
| 2026-06-08 00:00 |
04:31:57.33 |
+10:48:43.2 |
HIP 21176 |
12.22 |
| 2026-06-08 12:00 |
04:32:01.89 |
+10:48:48.7 |
HIP 21176 |
11.74 |
| 2026-06-09 00:00 |
04:32:06.45 |
+10:48:54.1 |
HIP 21176 |
11.35 |
| 2026-06-09 12:00 |
04:32:11.00 |
+10:48:59.3 |
HIP 21176 |
11.06 |
| 2026-06-10 00:00 |
04:32:15.54 |
+10:49:04.3 |
HIP 21176 |
10.87 |
| 2026-06-10 12:00 |
04:32:20.08 |
+10:49:09.3 |
HIP 21176 |
10.80 |
| 2026-06-11 00:00 |
04:32:24.60 |
+10:49:14.0 |
HIP 21176 |
10.84 |
| 2026-06-11 12:00 |
04:32:29.13 |
+10:49:18.7 |
HIP 21176 |
10.99 |
| 2026-06-12 00:00 |
04:32:33.64 |
+10:49:23.2 |
HIP 21176 |
11.24 |
| 2026-06-12 12:00 |
04:32:38.14 |
+10:49:27.5 |
HIP 21176 |
11.60 |
| 2026-06-13 00:00 |
04:32:42.64 |
+10:49:31.8 |
HIP 21176 |
12.04 |
| 2026-06-13 12:00 |
04:32:47.13 |
+10:49:35.8 |
HIP 21176 |
12.56 |
| 2026-06-14 00:00 |
04:32:51.61 |
+10:49:39.8 |
HIP 21176 |
13.15 |
| 2026-06-14 12:00 |
04:32:56.08 |
+10:49:43.5 |
HIP 21176 |
13.80 |
| 2026-06-15 00:00 |
04:33:00.53 |
+10:49:47.2 |
HIP 21176 |
14.50 |
| 2026-06-15 12:00 |
04:33:04.98 |
+10:49:50.6 |
HIP 21176 |
15.25 |
| 2026-06-16 00:00 |
04:33:09.42 |
+10:49:54.0 |
HIP 21176 |
16.03 |
| 2026-06-16 12:00 |
04:33:13.85 |
+10:49:57.2 |
HIP 21176 |
16.84 |
| 2026-06-17 00:00 |
04:33:18.26 |
+10:50:00.2 |
HIP 21176 |
17.68 |
| 2026-06-17 12:00 |
04:33:22.67 |
+10:50:03.1 |
HIP 21176 |
18.54 |
| 2026-06-18 00:00 |
04:33:27.06 |
+10:50:05.8 |
HIP 21176 |
19.42 |
| 2026-06-18 12:00 |
04:33:31.44 |
+10:50:08.4 |
HIP 21266 |
19.43 |
| 2026-06-19 00:00 |
04:33:35.81 |
+10:50:10.9 |
HIP 21266 |
19.30 |
| 2026-06-19 12:00 |
04:33:40.16 |
+10:50:13.1 |
HIP 21266 |
19.22 |
| 2026-06-20 00:00 |
04:33:44.50 |
+10:50:15.3 |
HIP 21266 |
19.20 |
| 2026-06-20 12:00 |
04:33:48.83 |
+10:50:17.3 |
HIP 21266 |
19.23 |
| 2026-06-21 00:00 |
04:33:53.14 |
+10:50:19.1 |
HIP 21266 |
19.33 |
| 2026-06-21 12:00 |
04:33:57.44 |
+10:50:20.8 |
HIP 21266 |
19.47 |
| 2026-06-22 00:00 |
04:34:01.73 |
+10:50:22.3 |
HIP 21266 |
19.67 |