| 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) |
| 2026-07-29 00:00 |
13:17:39.01 |
+04:06:06.9 |
HIP 64917 |
23.59 |
| 2026-07-29 12:00 |
13:17:41.98 |
+04:05:32.7 |
HIP 64917 |
22.75 |
| 2026-07-30 00:00 |
13:17:45.00 |
+04:04:58.3 |
HIP 64917 |
21.91 |
| 2026-07-30 12:00 |
13:17:48.08 |
+04:04:23.6 |
HIP 64917 |
21.06 |
| 2026-07-31 00:00 |
13:17:51.20 |
+04:03:48.8 |
HIP 64917 |
20.22 |
| 2026-07-31 12:00 |
13:17:54.37 |
+04:03:13.7 |
HIP 64917 |
19.38 |
| 2026-08-01 00:00 |
13:17:57.59 |
+04:02:38.4 |
HIP 64917 |
18.55 |
| 2026-08-01 12:00 |
13:18:00.86 |
+04:02:02.8 |
HIP 64917 |
17.73 |
| 2026-08-02 00:00 |
13:18:04.18 |
+04:01:27.1 |
HIP 64917 |
16.93 |
| 2026-08-02 12:00 |
13:18:07.55 |
+04:00:51.2 |
HIP 64917 |
16.14 |
| 2026-08-03 00:00 |
13:18:10.96 |
+04:00:15.0 |
HIP 64917 |
15.37 |
| 2026-08-03 12:00 |
13:18:14.42 |
+03:59:38.6 |
HIP 64917 |
14.63 |
| 2026-08-04 00:00 |
13:18:17.93 |
+03:59:02.1 |
HIP 64917 |
13.93 |
| 2026-08-04 12:00 |
13:18:21.49 |
+03:58:25.3 |
HIP 64917 |
13.28 |
| 2026-08-05 00:00 |
13:18:25.10 |
+03:57:48.3 |
HIP 64917 |
12.68 |
| 2026-08-05 12:00 |
13:18:28.75 |
+03:57:11.2 |
HIP 64917 |
12.15 |
| 2026-08-06 00:00 |
13:18:32.45 |
+03:56:33.8 |
HIP 64917 |
11.69 |
| 2026-08-06 12:00 |
13:18:36.20 |
+03:55:56.2 |
HIP 64917 |
11.33 |
| 2026-08-07 00:00 |
13:18:39.99 |
+03:55:18.5 |
HIP 64917 |
11.08 |
| 2026-08-07 12:00 |
13:18:43.83 |
+03:54:40.5 |
HIP 64917 |
10.93 |
| 2026-08-08 00:00 |
13:18:47.72 |
+03:54:02.4 |
HIP 64917 |
10.92 |
| 2026-08-08 12:00 |
13:18:51.65 |
+03:53:24.1 |
HIP 64983 |
10.71 |
| 2026-08-09 00:00 |
13:18:55.63 |
+03:52:45.6 |
HIP 64983 |
9.79 |
| 2026-08-09 12:00 |
13:18:59.65 |
+03:52:06.9 |
HIP 64983 |
8.92 |
| 2026-08-10 00:00 |
13:19:03.72 |
+03:51:28.1 |
HIP 64983 |
8.13 |
| 2026-08-10 12:00 |
13:19:07.84 |
+03:50:49.1 |
HIP 64983 |
7.45 |
| 2026-08-11 00:00 |
13:19:12.00 |
+03:50:09.9 |
HIP 64983 |
6.92 |
| 2026-08-11 12:00 |
13:19:16.20 |
+03:49:30.5 |
HIP 64983 |
6.58 |
| 2026-08-12 00:00 |
13:19:20.45 |
+03:48:51.0 |
HIP 64983 |
6.46 |
| 2026-08-12 12:00 |
13:19:24.74 |
+03:48:11.3 |
HIP 64983 |
6.59 |
| 2026-08-13 00:00 |
13:19:29.08 |
+03:47:31.4 |
HIP 64983 |
6.96 |
| 2026-08-13 12:00 |
13:19:33.46 |
+03:46:51.4 |
HIP 64983 |
7.53 |
| 2026-08-14 00:00 |
13:19:37.89 |
+03:46:11.3 |
HIP 64983 |
8.27 |
| 2026-08-14 12:00 |
13:19:42.36 |
+03:45:30.9 |
HIP 64983 |
9.15 |
| 2026-08-15 00:00 |
13:19:46.87 |
+03:44:50.5 |
HIP 64983 |
10.13 |
| 2026-08-15 12:00 |
13:19:51.42 |
+03:44:09.9 |
HIP 64983 |
11.19 |
| 2026-08-16 00:00 |
13:19:56.02 |
+03:43:29.1 |
HIP 64983 |
12.30 |
| 2026-08-16 12:00 |
13:20:00.66 |
+03:42:48.2 |
HIP 64983 |
13.47 |
| 2026-08-17 00:00 |
13:20:05.34 |
+03:42:07.2 |
HIP 64983 |
14.68 |
| 2026-08-17 12:00 |
13:20:10.06 |
+03:41:26.0 |
HIP 64983 |
15.93 |
| 2026-08-18 00:00 |
13:20:14.83 |
+03:40:44.7 |
HIP 64983 |
17.20 |
| 2026-08-18 12:00 |
13:20:19.63 |
+03:40:03.3 |
HIP 64983 |
18.49 |
| 2026-08-19 00:00 |
13:20:24.47 |
+03:39:21.8 |
HIP 64983 |
19.81 |