| Parameter |
Value |
| Designation |
C/2017 F2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-11-26T04:31:31.609920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:32Z |
| Obs used |
73 |
| NEO |
- |
| M1 |
7.000 |
| K1 |
11.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-09-02.0000000 |
| e |
1.00519546 |
| q (au) |
6.927697 |
| a (au) |
-1333.414094 |
| i (deg) |
42.507666 |
| Ω (om, deg) |
38.668006 |
| ω (w, deg) |
134.901946 |
| M (ma, deg) |
-0.001724 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.109 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.109 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.999 |
| 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) |
| 2026-05-12 00:00 |
18:21:57.27 |
-60:42:11.7 |
HIP 90089 |
8.66 |
| 2026-05-12 12:00 |
18:21:50.26 |
-60:43:00.9 |
HIP 90089 |
9.27 |
| 2026-05-13 00:00 |
18:21:43.16 |
-60:43:49.7 |
HIP 90089 |
10.00 |
| 2026-05-13 12:00 |
18:21:35.98 |
-60:44:38.2 |
HIP 90089 |
10.82 |
| 2026-05-14 00:00 |
18:21:28.71 |
-60:45:26.3 |
HIP 90089 |
11.71 |
| 2026-05-14 12:00 |
18:21:21.36 |
-60:46:14.1 |
HIP 90089 |
12.66 |
| 2026-05-15 00:00 |
18:21:13.93 |
-60:47:01.5 |
HIP 90089 |
13.65 |
| 2026-05-15 12:00 |
18:21:06.42 |
-60:47:48.5 |
HIP 90089 |
14.69 |
| 2026-05-16 00:00 |
18:20:58.82 |
-60:48:35.1 |
HIP 90089 |
15.76 |
| 2026-05-16 12:00 |
18:20:51.15 |
-60:49:21.3 |
HIP 90089 |
16.85 |
| 2026-05-17 00:00 |
18:20:43.39 |
-60:50:07.2 |
HIP 90089 |
17.97 |
| 2026-05-17 12:00 |
18:20:35.56 |
-60:50:52.7 |
HIP 90089 |
19.11 |
| 2026-05-18 00:00 |
18:20:27.65 |
-60:51:37.7 |
HIP 90089 |
20.26 |
| 2026-05-18 12:00 |
18:20:19.66 |
-60:52:22.4 |
HIP 90089 |
21.42 |
| 2026-05-19 00:00 |
18:20:11.59 |
-60:53:06.6 |
HIP 90089 |
22.60 |
| 2026-05-19 12:00 |
18:20:03.45 |
-60:53:50.5 |
HIP 89695 |
22.57 |
| 2026-05-20 00:00 |
18:19:55.24 |
-60:54:33.9 |
HIP 89695 |
21.41 |
| 2026-05-20 12:00 |
18:19:46.95 |
-60:55:16.9 |
HIP 89695 |
20.27 |
| 2026-05-21 00:00 |
18:19:38.59 |
-60:55:59.5 |
HIP 89695 |
19.14 |
| 2026-05-21 12:00 |
18:19:30.16 |
-60:56:41.7 |
HIP 89695 |
18.02 |
| 2026-05-22 00:00 |
18:19:21.66 |
-60:57:23.4 |
HIP 89695 |
16.93 |
| 2026-05-22 12:00 |
18:19:13.09 |
-60:58:04.7 |
HIP 89695 |
15.86 |
| 2026-05-23 00:00 |
18:19:04.45 |
-60:58:45.6 |
HIP 89695 |
14.82 |
| 2026-05-23 12:00 |
18:18:55.74 |
-60:59:26.0 |
HIP 89695 |
13.82 |
| 2026-05-24 00:00 |
18:18:46.96 |
-61:00:06.0 |
HIP 89695 |
12.87 |
| 2026-05-24 12:00 |
18:18:38.12 |
-61:00:45.5 |
HIP 89695 |
11.98 |
| 2026-05-25 00:00 |
18:18:29.22 |
-61:01:24.6 |
HIP 89695 |
11.17 |
| 2026-05-25 12:00 |
18:18:20.25 |
-61:02:03.3 |
HIP 89695 |
10.46 |
| 2026-05-26 00:00 |
18:18:11.21 |
-61:02:41.5 |
HIP 89695 |
9.86 |
| 2026-05-26 12:00 |
18:18:02.12 |
-61:03:19.2 |
HIP 89695 |
9.41 |
| 2026-05-27 00:00 |
18:17:52.96 |
-61:03:56.5 |
HIP 89695 |
9.12 |
| 2026-05-27 12:00 |
18:17:43.74 |
-61:04:33.3 |
HIP 89695 |
9.01 |
| 2026-05-28 00:00 |
18:17:34.47 |
-61:05:09.6 |
HIP 89695 |
9.08 |
| 2026-05-28 12:00 |
18:17:25.13 |
-61:05:45.5 |
HIP 89695 |
9.35 |
| 2026-05-29 00:00 |
18:17:15.74 |
-61:06:20.9 |
HIP 89695 |
9.78 |
| 2026-05-29 12:00 |
18:17:06.29 |
-61:06:55.8 |
HIP 89695 |
10.36 |
| 2026-05-30 00:00 |
18:16:56.79 |
-61:07:30.2 |
HIP 89695 |
11.07 |
| 2026-05-30 12:00 |
18:16:47.23 |
-61:08:04.2 |
HIP 89695 |
11.89 |
| 2026-05-31 00:00 |
18:16:37.61 |
-61:08:37.7 |
HIP 89695 |
12.79 |
| 2026-05-31 12:00 |
18:16:27.95 |
-61:09:10.7 |
HIP 89695 |
13.76 |
| 2026-06-01 00:00 |
18:16:18.23 |
-61:09:43.2 |
HIP 89695 |
14.78 |
| 2026-06-01 12:00 |
18:16:08.46 |
-61:10:15.2 |
HIP 89695 |
15.85 |
| 2026-06-02 00:00 |
18:15:58.64 |
-61:10:46.7 |
HIP 89695 |
16.96 |