| Parameter |
Value |
| Designation |
C/1998 K5 (LINEAR) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1998-07-17T10:42:32.613120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:53Z |
| Obs used |
627 |
| NEO |
- |
| M1 |
15.300 |
| K1 |
28.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1998-07-27.0000000 |
| e |
0.98669128 |
| q (au) |
0.963547 |
| a (au) |
72.399650 |
| i (deg) |
9.927137 |
| Ω (om, deg) |
211.117668 |
| ω (w, deg) |
99.460270 |
| M (ma, deg) |
0.015285 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.295 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.295 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.851 |
| k |
0.939 |
| δ90 |
1.000 |
| 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 |
| 1998-05-26 |
1998-06-15 |
+45.9853 |
-1.403 |
| 1998-06-15 |
1998-07-16 |
+6.3263 |
+0.583 |
| 1998-07-17 |
1998-09-22 |
-11.0269 |
-0.952 |
| 1998-09-22 |
1998-10-31 |
+26.5628 |
-7.342 |
| 1998-10-31 |
1998-12-19 |
-18.5111 |
+5.933 |
| 1998-12-19 |
1999-02-14 |
-0.4311 |
-1.229 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
07:53:00.85 |
+10:55:20.8 |
HIP 38547 |
16.68 |
| 2026-09-20 12:00 |
07:53:02.10 |
+10:55:11.6 |
HIP 38547 |
16.39 |
| 2026-09-21 00:00 |
07:53:03.33 |
+10:55:02.4 |
HIP 38547 |
16.10 |
| 2026-09-21 12:00 |
07:53:04.54 |
+10:54:53.3 |
HIP 38547 |
15.82 |
| 2026-09-22 00:00 |
07:53:05.74 |
+10:54:44.1 |
HIP 38547 |
15.54 |
| 2026-09-22 12:00 |
07:53:06.91 |
+10:54:35.0 |
HIP 38547 |
15.27 |
| 2026-09-23 00:00 |
07:53:08.07 |
+10:54:26.0 |
HIP 38547 |
15.00 |
| 2026-09-23 12:00 |
07:53:09.21 |
+10:54:16.9 |
HIP 38547 |
14.73 |
| 2026-09-24 00:00 |
07:53:10.33 |
+10:54:07.9 |
HIP 38547 |
14.47 |
| 2026-09-24 12:00 |
07:53:11.43 |
+10:53:58.9 |
HIP 38547 |
14.22 |
| 2026-09-25 00:00 |
07:53:12.51 |
+10:53:49.9 |
HIP 38547 |
13.97 |
| 2026-09-25 12:00 |
07:53:13.58 |
+10:53:41.0 |
HIP 38547 |
13.72 |
| 2026-09-26 00:00 |
07:53:14.62 |
+10:53:32.1 |
HIP 38547 |
13.48 |
| 2026-09-26 12:00 |
07:53:15.65 |
+10:53:23.2 |
HIP 38547 |
13.24 |
| 2026-09-27 00:00 |
07:53:16.65 |
+10:53:14.3 |
HIP 38547 |
13.01 |
| 2026-09-27 12:00 |
07:53:17.64 |
+10:53:05.5 |
HIP 38547 |
12.78 |
| 2026-09-28 00:00 |
07:53:18.60 |
+10:52:56.7 |
HIP 38547 |
12.56 |
| 2026-09-28 12:00 |
07:53:19.55 |
+10:52:47.9 |
HIP 38547 |
12.34 |
| 2026-09-29 00:00 |
07:53:20.48 |
+10:52:39.2 |
HIP 38547 |
12.13 |
| 2026-09-29 12:00 |
07:53:21.38 |
+10:52:30.5 |
HIP 38547 |
11.92 |
| 2026-09-30 00:00 |
07:53:22.27 |
+10:52:21.8 |
HIP 38547 |
11.71 |
| 2026-09-30 12:00 |
07:53:23.14 |
+10:52:13.2 |
HIP 38547 |
11.51 |
| 2026-10-01 00:00 |
07:53:23.99 |
+10:52:04.6 |
HIP 38547 |
11.31 |
| 2026-10-01 12:00 |
07:53:24.81 |
+10:51:56.1 |
HIP 38547 |
11.12 |
| 2026-10-02 00:00 |
07:53:25.62 |
+10:51:47.5 |
HIP 38547 |
10.93 |
| 2026-10-02 12:00 |
07:53:26.41 |
+10:51:39.1 |
HIP 38547 |
10.74 |
| 2026-10-03 00:00 |
07:53:27.18 |
+10:51:30.6 |
HIP 38547 |
10.56 |
| 2026-10-03 12:00 |
07:53:27.92 |
+10:51:22.2 |
HIP 38547 |
10.39 |
| 2026-10-04 00:00 |
07:53:28.65 |
+10:51:13.8 |
HIP 38547 |
10.21 |
| 2026-10-04 12:00 |
07:53:29.35 |
+10:51:05.5 |
HIP 38547 |
10.04 |
| 2026-10-05 00:00 |
07:53:30.04 |
+10:50:57.2 |
HIP 38547 |
9.88 |
| 2026-10-05 12:00 |
07:53:30.70 |
+10:50:49.0 |
HIP 38547 |
9.71 |
| 2026-10-06 00:00 |
07:53:31.35 |
+10:50:40.7 |
HIP 38547 |
9.55 |
| 2026-10-06 12:00 |
07:53:31.97 |
+10:50:32.6 |
HIP 38547 |
9.40 |
| 2026-10-07 00:00 |
07:53:32.57 |
+10:50:24.5 |
HIP 38547 |
9.25 |
| 2026-10-07 12:00 |
07:53:33.15 |
+10:50:16.4 |
HIP 38547 |
9.10 |
| 2026-10-08 00:00 |
07:53:33.71 |
+10:50:08.3 |
HIP 38547 |
8.95 |
| 2026-10-08 12:00 |
07:53:34.25 |
+10:50:00.4 |
HIP 38547 |
8.80 |
| 2026-10-09 00:00 |
07:53:34.77 |
+10:49:52.4 |
HIP 38547 |
8.66 |
| 2026-10-09 12:00 |
07:53:35.27 |
+10:49:44.5 |
HIP 38547 |
8.53 |
| 2026-10-10 00:00 |
07:53:35.74 |
+10:49:36.7 |
HIP 38547 |
8.39 |
| 2026-10-10 12:00 |
07:53:36.19 |
+10:49:28.9 |
HIP 38547 |
8.26 |
| 2026-10-11 00:00 |
07:53:36.63 |
+10:49:21.1 |
HIP 38547 |
8.13 |