C/2017 K5 (PANSTARRS)
| 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) |
| 2026-02-03 00:00 |
02:44:50.82 |
-73:28:11.1 |
HIP 13119 |
27.71 |
| 2026-02-03 12:00 |
02:44:57.62 |
-73:25:52.3 |
HIP 12445 |
26.57 |
| 2026-02-04 00:00 |
02:45:04.62 |
-73:23:33.7 |
HIP 12445 |
25.58 |
| 2026-02-04 12:00 |
02:45:11.82 |
-73:21:15.0 |
HIP 12445 |
24.80 |
| 2026-02-05 00:00 |
02:45:19.22 |
-73:18:56.4 |
HIP 12960 |
23.79 |
| 2026-02-05 12:00 |
02:45:26.82 |
-73:16:37.8 |
HIP 12960 |
21.41 |
| 2026-02-06 00:00 |
02:45:34.61 |
-73:14:19.3 |
HIP 12960 |
19.04 |
| 2026-02-06 12:00 |
02:45:42.61 |
-73:12:00.9 |
HIP 12960 |
16.66 |
| 2026-02-07 00:00 |
02:45:50.79 |
-73:09:42.5 |
HIP 12960 |
14.28 |
| 2026-02-07 12:00 |
02:45:59.17 |
-73:07:24.3 |
HIP 12960 |
11.90 |
| 2026-02-08 00:00 |
02:46:07.74 |
-73:05:06.1 |
HIP 12960 |
9.51 |
| 2026-02-08 12:00 |
02:46:16.49 |
-73:02:48.0 |
HIP 12960 |
7.12 |
| 2026-02-09 00:00 |
02:46:25.44 |
-73:00:30.0 |
HIP 12960 |
4.73 |
| 2026-02-09 12:00 |
02:46:34.57 |
-72:58:12.1 |
HIP 12960 |
2.35 |
| 2026-02-10 00:00 |
02:46:43.89 |
-72:55:54.3 |
HIP 12960 |
0.25 |
| 2026-02-10 12:00 |
02:46:53.40 |
-72:53:36.7 |
HIP 12960 |
2.47 |
| 2026-02-11 00:00 |
02:47:03.08 |
-72:51:19.2 |
HIP 12960 |
4.87 |
| 2026-02-11 12:00 |
02:47:12.95 |
-72:49:01.8 |
HIP 12960 |
7.27 |
| 2026-02-12 00:00 |
02:47:23.00 |
-72:46:44.5 |
HIP 12960 |
9.68 |
| 2026-02-12 12:00 |
02:47:33.23 |
-72:44:27.4 |
HIP 12960 |
12.08 |
| 2026-02-13 00:00 |
02:47:43.63 |
-72:42:10.5 |
HIP 13227 |
13.51 |
| 2026-02-13 12:00 |
02:47:54.21 |
-72:39:53.8 |
HIP 13227 |
14.26 |
| 2026-02-14 00:00 |
02:48:04.97 |
-72:37:37.2 |
HIP 13227 |
15.35 |
| 2026-02-14 12:00 |
02:48:15.90 |
-72:35:20.8 |
HIP 13227 |
16.70 |
| 2026-02-15 00:00 |
02:48:27.00 |
-72:33:04.5 |
HIP 13227 |
18.26 |
| 2026-02-15 12:00 |
02:48:38.28 |
-72:30:48.5 |
HIP 13227 |
19.99 |
| 2026-02-16 00:00 |
02:48:49.72 |
-72:28:32.7 |
HIP 13227 |
21.84 |
| 2026-02-16 12:00 |
02:49:01.33 |
-72:26:17.0 |
HIP 13227 |
23.78 |
| 2026-02-17 00:00 |
02:49:13.10 |
-72:24:01.6 |
HIP 13227 |
25.80 |
| 2026-02-17 12:00 |
02:49:25.05 |
-72:21:46.4 |
HIP 13227 |
27.87 |
| 2026-02-18 00:00 |
02:49:37.15 |
-72:19:31.5 |
HIP 13227 |
30.00 |
| 2026-02-18 12:00 |
02:49:49.42 |
-72:17:16.7 |
HIP 13227 |
32.16 |
| 2026-02-19 00:00 |
02:50:01.85 |
-72:15:02.2 |
HIP 12895 |
31.36 |
| 2026-02-19 12:00 |
02:50:14.44 |
-72:12:48.0 |
HIP 12895 |
30.33 |
| 2026-02-20 00:00 |
02:50:27.18 |
-72:10:34.0 |
HIP 12895 |
29.48 |
| 2026-02-20 12:00 |
02:50:40.08 |
-72:08:20.3 |
HIP 12895 |
28.82 |
| 2026-02-21 00:00 |
02:50:53.14 |
-72:06:06.9 |
HIP 12895 |
28.38 |
| 2026-02-21 12:00 |
02:51:06.35 |
-72:03:53.7 |
HIP 13676 |
28.11 |
| 2026-02-22 00:00 |
02:51:19.72 |
-72:01:40.8 |
HIP 13676 |
26.09 |
| 2026-02-22 12:00 |
02:51:33.23 |
-71:59:28.2 |
HIP 13676 |
24.14 |
| 2026-02-23 00:00 |
02:51:46.89 |
-71:57:15.9 |
HIP 13676 |
22.27 |
| 2026-02-23 12:00 |
02:52:00.70 |
-71:55:03.8 |
HIP 13676 |
20.51 |
| 2026-02-24 00:00 |
02:52:14.66 |
-71:52:52.1 |
HIP 13676 |
18.90 |