| Parameter |
Value |
| Designation |
C/2017 K5 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-03-22T10:59:03.560640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:35Z |
| Obs used |
116 |
| NEO |
- |
| M1 |
6.600 |
| K1 |
8.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-02-28.0000000 |
| e |
1.00422212 |
| q (au) |
7.680279 |
| a (au) |
-1819.058463 |
| i (deg) |
82.257758 |
| Ω (om, deg) |
102.375800 |
| ω (w, deg) |
171.715759 |
| M (ma, deg) |
-0.004935 |
Magnitude
Scatter + Global Linear
$$
M_a = (-0.133 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
-0.133 |
| n |
6.000 |
| gf |
0.978 |
| gb |
-0.500 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2017-05-27 |
2020-03-20 |
+13.4876 |
-12.439 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
03:45:38.66 |
-67:59:10.0 |
HIP 17249 |
25.03 |
| 2026-05-12 12:00 |
03:46:02.58 |
-67:58:31.7 |
HIP 17249 |
27.33 |
| 2026-05-13 00:00 |
03:46:26.51 |
-67:57:54.1 |
HIP 17249 |
29.62 |
| 2026-05-13 12:00 |
03:46:50.44 |
-67:57:17.4 |
HIP 17249 |
31.92 |
| 2026-05-14 00:00 |
03:47:14.36 |
-67:56:41.4 |
HIP 17249 |
34.21 |
| 2026-05-14 12:00 |
03:47:38.28 |
-67:56:06.1 |
HIP 17249 |
36.51 |
| 2026-05-15 00:00 |
03:48:02.20 |
-67:55:31.7 |
HIP 17249 |
38.80 |
| 2026-05-15 12:00 |
03:48:26.11 |
-67:54:58.0 |
HIP 17249 |
41.09 |
| 2026-05-16 00:00 |
03:48:50.02 |
-67:54:25.1 |
HIP 18249 |
42.01 |
| 2026-05-16 12:00 |
03:49:13.92 |
-67:53:53.0 |
HIP 18249 |
40.02 |
| 2026-05-17 00:00 |
03:49:37.81 |
-67:53:21.7 |
HIP 18249 |
38.08 |
| 2026-05-17 12:00 |
03:50:01.70 |
-67:52:51.2 |
HIP 18249 |
36.19 |
| 2026-05-18 00:00 |
03:50:25.58 |
-67:52:21.4 |
HIP 18249 |
34.36 |
| 2026-05-18 12:00 |
03:50:49.45 |
-67:51:52.5 |
HIP 18249 |
32.61 |
| 2026-05-19 00:00 |
03:51:13.31 |
-67:51:24.3 |
HIP 18249 |
30.94 |
| 2026-05-19 12:00 |
03:51:37.15 |
-67:50:56.9 |
HIP 18249 |
29.37 |
| 2026-05-20 00:00 |
03:52:00.99 |
-67:50:30.2 |
HIP 18249 |
27.92 |
| 2026-05-20 12:00 |
03:52:24.81 |
-67:50:04.4 |
HIP 18249 |
26.60 |
| 2026-05-21 00:00 |
03:52:48.62 |
-67:49:39.3 |
HIP 18249 |
25.43 |
| 2026-05-21 12:00 |
03:53:12.42 |
-67:49:15.1 |
HIP 18249 |
24.44 |
| 2026-05-22 00:00 |
03:53:36.20 |
-67:48:51.6 |
HIP 18249 |
23.65 |
| 2026-05-22 12:00 |
03:53:59.96 |
-67:48:28.8 |
HIP 18249 |
23.07 |
| 2026-05-23 00:00 |
03:54:23.71 |
-67:48:06.9 |
HIP 18249 |
22.72 |
| 2026-05-23 12:00 |
03:54:47.44 |
-67:47:45.7 |
HIP 18249 |
22.61 |
| 2026-05-24 00:00 |
03:55:11.16 |
-67:47:25.4 |
HIP 18249 |
22.75 |
| 2026-05-24 12:00 |
03:55:34.85 |
-67:47:05.7 |
HIP 18249 |
23.12 |
| 2026-05-25 00:00 |
03:55:58.53 |
-67:46:46.9 |
HIP 18249 |
23.72 |
| 2026-05-25 12:00 |
03:56:22.18 |
-67:46:28.9 |
HIP 18249 |
24.52 |
| 2026-05-26 00:00 |
03:56:45.81 |
-67:46:11.6 |
HIP 18249 |
25.52 |
| 2026-05-26 12:00 |
03:57:09.43 |
-67:45:55.1 |
HIP 18249 |
26.67 |
| 2026-05-27 00:00 |
03:57:33.02 |
-67:45:39.3 |
HIP 18249 |
27.98 |
| 2026-05-27 12:00 |
03:57:56.59 |
-67:45:24.4 |
HIP 18249 |
29.41 |
| 2026-05-28 00:00 |
03:58:20.13 |
-67:45:10.2 |
HIP 18249 |
30.94 |
| 2026-05-28 12:00 |
03:58:43.65 |
-67:44:56.8 |
HIP 18249 |
32.57 |
| 2026-05-29 00:00 |
03:59:07.15 |
-67:44:44.1 |
HIP 18249 |
34.27 |
| 2026-05-29 12:00 |
03:59:30.62 |
-67:44:32.2 |
HIP 18249 |
36.03 |
| 2026-05-30 00:00 |
03:59:54.07 |
-67:44:21.1 |
HIP 18739 |
35.86 |
| 2026-05-30 12:00 |
04:00:17.49 |
-67:44:10.8 |
HIP 19154 |
34.51 |
| 2026-05-31 00:00 |
04:00:40.88 |
-67:44:01.2 |
HIP 19154 |
32.28 |
| 2026-05-31 12:00 |
04:01:04.24 |
-67:43:52.4 |
HIP 19154 |
30.07 |
| 2026-06-01 00:00 |
04:01:27.58 |
-67:43:44.4 |
HIP 19154 |
27.85 |
| 2026-06-01 12:00 |
04:01:50.89 |
-67:43:37.1 |
HIP 19154 |
25.64 |
| 2026-06-02 00:00 |
04:02:14.16 |
-67:43:30.6 |
HIP 19154 |
23.43 |