| Parameter |
Value |
| Designation |
C/2017 K6 (Jacques) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-01-03T03:16:30.506880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:34Z |
| Obs used |
475 |
| NEO |
- |
| M1 |
12.100 |
| K1 |
6.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2018-02-05.0000000 |
| e |
0.99822114 |
| q (au) |
2.002756 |
| a (au) |
1125.867222 |
| i (deg) |
57.251183 |
| Ω (om, deg) |
85.054187 |
| ω (w, deg) |
303.838384 |
| M (ma, deg) |
0.000857 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.455 + 4.414\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.455 |
| n |
4.414 |
| gf |
1.000 |
| gb |
-0.891 |
| k |
0.984 |
| δ90 |
10.000 |
| 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 |
| 2017-05-29 |
2017-09-21 |
-1.7754 |
+1.104 |
| 2017-09-21 |
2017-12-30 |
+16.2254 |
-5.376 |
| 2018-01-05 |
2019-02-14 |
+1.6841 |
-1.364 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
13:50:31.30 |
+55:33:19.5 |
HIP 67595 |
8.50 |
| 2026-03-26 12:00 |
13:50:23.36 |
+55:33:58.2 |
HIP 67595 |
8.65 |
| 2026-03-27 00:00 |
13:50:15.38 |
+55:34:36.3 |
HIP 67595 |
9.00 |
| 2026-03-27 12:00 |
13:50:07.37 |
+55:35:13.8 |
HIP 67595 |
9.52 |
| 2026-03-28 00:00 |
13:49:59.33 |
+55:35:50.6 |
HIP 67595 |
10.19 |
| 2026-03-28 12:00 |
13:49:51.26 |
+55:36:26.8 |
HIP 67595 |
10.98 |
| 2026-03-29 00:00 |
13:49:43.15 |
+55:37:02.3 |
HIP 67595 |
11.86 |
| 2026-03-29 12:00 |
13:49:35.01 |
+55:37:37.2 |
HIP 67595 |
12.82 |
| 2026-03-30 00:00 |
13:49:26.85 |
+55:38:11.5 |
HIP 67595 |
13.83 |
| 2026-03-30 12:00 |
13:49:18.65 |
+55:38:45.1 |
HIP 67595 |
14.90 |
| 2026-03-31 00:00 |
13:49:10.43 |
+55:39:18.0 |
HIP 67595 |
16.00 |
| 2026-03-31 12:00 |
13:49:02.17 |
+55:39:50.3 |
HIP 67595 |
17.13 |
| 2026-04-01 00:00 |
13:48:53.89 |
+55:40:22.0 |
HIP 67595 |
18.28 |
| 2026-04-01 12:00 |
13:48:45.59 |
+55:40:52.9 |
HIP 67595 |
19.45 |
| 2026-04-02 00:00 |
13:48:37.26 |
+55:41:23.3 |
HIP 67595 |
20.64 |
| 2026-04-02 12:00 |
13:48:28.90 |
+55:41:52.9 |
HIP 67595 |
21.84 |
| 2026-04-03 00:00 |
13:48:20.52 |
+55:42:21.9 |
HIP 67595 |
23.05 |
| 2026-04-03 12:00 |
13:48:12.12 |
+55:42:50.2 |
HIP 67595 |
24.27 |
| 2026-04-04 00:00 |
13:48:03.70 |
+55:43:17.8 |
HIP 67595 |
25.49 |
| 2026-04-04 12:00 |
13:47:55.25 |
+55:43:44.8 |
HIP 67103 |
24.52 |
| 2026-04-05 00:00 |
13:47:46.79 |
+55:44:11.1 |
HIP 67103 |
23.25 |
| 2026-04-05 12:00 |
13:47:38.30 |
+55:44:36.7 |
HIP 67103 |
21.98 |
| 2026-04-06 00:00 |
13:47:29.80 |
+55:45:01.7 |
HIP 67103 |
20.72 |
| 2026-04-06 12:00 |
13:47:21.28 |
+55:45:25.9 |
HIP 67103 |
19.46 |
| 2026-04-07 00:00 |
13:47:12.74 |
+55:45:49.5 |
HIP 67103 |
18.20 |
| 2026-04-07 12:00 |
13:47:04.18 |
+55:46:12.3 |
HIP 67103 |
16.94 |
| 2026-04-08 00:00 |
13:46:55.61 |
+55:46:34.5 |
HIP 67103 |
15.69 |
| 2026-04-08 12:00 |
13:46:47.02 |
+55:46:56.0 |
HIP 67103 |
14.44 |
| 2026-04-09 00:00 |
13:46:38.42 |
+55:47:16.8 |
HIP 67103 |
13.19 |
| 2026-04-09 12:00 |
13:46:29.81 |
+55:47:37.0 |
HIP 67103 |
11.96 |
| 2026-04-10 00:00 |
13:46:21.19 |
+55:47:56.4 |
HIP 67103 |
10.73 |
| 2026-04-10 12:00 |
13:46:12.55 |
+55:48:15.1 |
HIP 67103 |
9.51 |
| 2026-04-11 00:00 |
13:46:03.90 |
+55:48:33.1 |
HIP 67103 |
8.31 |
| 2026-04-11 12:00 |
13:45:55.24 |
+55:48:50.4 |
HIP 67103 |
7.12 |
| 2026-04-12 00:00 |
13:45:46.58 |
+55:49:07.1 |
HIP 67103 |
5.98 |
| 2026-04-12 12:00 |
13:45:37.91 |
+55:49:23.0 |
HIP 67103 |
4.89 |
| 2026-04-13 00:00 |
13:45:29.22 |
+55:49:38.2 |
HIP 67103 |
3.90 |
| 2026-04-13 12:00 |
13:45:20.54 |
+55:49:52.7 |
HIP 67103 |
3.11 |
| 2026-04-14 00:00 |
13:45:11.85 |
+55:50:06.5 |
HIP 67103 |
2.71 |
| 2026-04-14 12:00 |
13:45:03.15 |
+55:50:19.6 |
HIP 67103 |
2.85 |
| 2026-04-15 00:00 |
13:44:54.45 |
+55:50:31.9 |
HIP 67103 |
3.47 |
| 2026-04-15 12:00 |
13:44:45.75 |
+55:50:43.6 |
HIP 67103 |
4.37 |
| 2026-04-16 00:00 |
13:44:37.04 |
+55:50:54.6 |
HIP 67103 |
5.41 |