| Parameter |
Value |
| Designation |
C/2017 U5 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-12-19T02:35:57.655680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:37Z |
| Obs used |
92 |
| NEO |
- |
| M1 |
11.800 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-11-25.0000000 |
| e |
0.74456954 |
| q (au) |
4.326737 |
| a (au) |
16.939001 |
| i (deg) |
18.956551 |
| Ω (om, deg) |
163.115368 |
| ω (w, deg) |
262.150770 |
| M (ma, deg) |
359.659169 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.300 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.300 |
| n |
2.000 |
| 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) |
| 2026-09-20 00:00 |
13:26:45.74 |
+02:52:36.1 |
HIP 65538 |
9.50 |
| 2026-09-20 12:00 |
13:26:52.59 |
+02:51:51.8 |
HIP 65538 |
11.31 |
| 2026-09-21 00:00 |
13:26:59.46 |
+02:51:07.6 |
HIP 65538 |
13.13 |
| 2026-09-21 12:00 |
13:27:06.35 |
+02:50:23.4 |
HIP 65654 |
13.82 |
| 2026-09-22 00:00 |
13:27:13.25 |
+02:49:39.3 |
HIP 65654 |
13.50 |
| 2026-09-22 12:00 |
13:27:20.18 |
+02:48:55.2 |
HIP 65654 |
13.43 |
| 2026-09-23 00:00 |
13:27:27.13 |
+02:48:11.2 |
HIP 65654 |
13.62 |
| 2026-09-23 12:00 |
13:27:34.09 |
+02:47:27.2 |
HIP 65654 |
14.06 |
| 2026-09-24 00:00 |
13:27:41.07 |
+02:46:43.3 |
HIP 65654 |
14.73 |
| 2026-09-24 12:00 |
13:27:48.07 |
+02:45:59.5 |
HIP 65654 |
15.61 |
| 2026-09-25 00:00 |
13:27:55.08 |
+02:45:15.7 |
HIP 65654 |
16.65 |
| 2026-09-25 12:00 |
13:28:02.12 |
+02:44:32.0 |
HIP 65654 |
17.83 |
| 2026-09-26 00:00 |
13:28:09.17 |
+02:43:48.3 |
HIP 65654 |
19.13 |
| 2026-09-26 12:00 |
13:28:16.23 |
+02:43:04.8 |
HIP 65654 |
20.53 |
| 2026-09-27 00:00 |
13:28:23.31 |
+02:42:21.3 |
HIP 65654 |
22.00 |
| 2026-09-27 12:00 |
13:28:30.41 |
+02:41:37.8 |
HIP 65852 |
21.69 |
| 2026-09-28 00:00 |
13:28:37.52 |
+02:40:54.5 |
HIP 65852 |
20.10 |
| 2026-09-28 12:00 |
13:28:44.65 |
+02:40:11.2 |
HIP 65852 |
18.56 |
| 2026-09-29 00:00 |
13:28:51.79 |
+02:39:28.1 |
HIP 65852 |
17.10 |
| 2026-09-29 12:00 |
13:28:58.94 |
+02:38:45.0 |
HIP 65852 |
15.73 |
| 2026-09-30 00:00 |
13:29:06.11 |
+02:38:01.9 |
HIP 65852 |
14.48 |
| 2026-09-30 12:00 |
13:29:13.29 |
+02:37:19.0 |
HIP 65852 |
13.40 |
| 2026-10-01 00:00 |
13:29:20.49 |
+02:36:36.2 |
HIP 65852 |
12.51 |
| 2026-10-01 12:00 |
13:29:27.70 |
+02:35:53.5 |
HIP 65852 |
11.88 |
| 2026-10-02 00:00 |
13:29:34.92 |
+02:35:10.8 |
HIP 65852 |
11.53 |
| 2026-10-02 12:00 |
13:29:42.15 |
+02:34:28.3 |
HIP 65852 |
11.50 |
| 2026-10-03 00:00 |
13:29:49.40 |
+02:33:45.8 |
HIP 65852 |
11.80 |
| 2026-10-03 12:00 |
13:29:56.66 |
+02:33:03.5 |
HIP 65852 |
12.39 |
| 2026-10-04 00:00 |
13:30:03.92 |
+02:32:21.3 |
HIP 65852 |
13.24 |
| 2026-10-04 12:00 |
13:30:11.20 |
+02:31:39.1 |
HIP 65852 |
14.31 |
| 2026-10-05 00:00 |
13:30:18.49 |
+02:30:57.1 |
HIP 65852 |
15.55 |
| 2026-10-05 12:00 |
13:30:25.79 |
+02:30:15.2 |
HIP 65852 |
16.92 |
| 2026-10-06 00:00 |
13:30:33.10 |
+02:29:33.5 |
HIP 65852 |
18.40 |
| 2026-10-06 12:00 |
13:30:40.42 |
+02:28:51.8 |
HIP 65852 |
19.96 |
| 2026-10-07 00:00 |
13:30:47.75 |
+02:28:10.3 |
HIP 65852 |
21.59 |
| 2026-10-07 12:00 |
13:30:55.08 |
+02:27:28.9 |
HIP 65852 |
23.26 |
| 2026-10-08 00:00 |
13:31:02.43 |
+02:26:47.6 |
HIP 65852 |
24.98 |
| 2026-10-08 12:00 |
13:31:09.78 |
+02:26:06.4 |
HIP 65852 |
26.72 |
| 2026-10-09 00:00 |
13:31:17.14 |
+02:25:25.4 |
HIP 65852 |
28.50 |
| 2026-10-09 12:00 |
13:31:24.51 |
+02:24:44.5 |
HIP 66071 |
28.38 |
| 2026-10-10 00:00 |
13:31:31.88 |
+02:24:03.8 |
HIP 66071 |
26.64 |
| 2026-10-10 12:00 |
13:31:39.26 |
+02:23:23.2 |
HIP 66071 |
24.94 |
| 2026-10-11 00:00 |
13:31:46.64 |
+02:22:42.7 |
HIP 66071 |
23.29 |