| Parameter |
Value |
| Designation |
99P/Kowal 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-04-08T01:35:09.070080Z |
| Orbit solution date (soln_date, UTC) |
2026-09-08T08:46:31Z |
| Obs used |
1734 |
| NEO |
- |
| M1 |
6.800 |
| K1 |
12.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-02-19.0000000 |
| e |
0.22981744 |
| q (au) |
4.724690 |
| a (au) |
6.134506 |
| i (deg) |
4.337792 |
| Ω (om, deg) |
28.179483 |
| ω (w, deg) |
174.196203 |
| M (ma, deg) |
191.012951 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.594 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.594 |
| n |
6.000 |
| gf |
0.995 |
| gb |
-0.500 |
| k |
1.000 |
| 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 |
| 2019-10-08 |
2022-04-08 |
+13.7752 |
-9.355 |
| 2022-04-08 |
2024-07-25 |
-7.7771 |
+5.047 |
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 |
22:05:15.32 |
-16:11:53.3 |
HIP 109062 |
22.08 |
| 2026-09-20 12:00 |
22:05:05.10 |
-16:12:32.0 |
HIP 109062 |
22.20 |
| 2026-09-21 00:00 |
22:04:54.99 |
-16:13:10.0 |
HIP 109062 |
22.60 |
| 2026-09-21 12:00 |
22:04:44.96 |
-16:13:47.3 |
HIP 109062 |
23.27 |
| 2026-09-22 00:00 |
22:04:35.04 |
-16:14:23.9 |
HIP 108918 |
22.88 |
| 2026-09-22 12:00 |
22:04:25.21 |
-16:14:59.8 |
HIP 108918 |
22.30 |
| 2026-09-23 00:00 |
22:04:15.49 |
-16:15:34.9 |
HIP 108918 |
21.96 |
| 2026-09-23 12:00 |
22:04:05.86 |
-16:16:09.4 |
HIP 108918 |
21.88 |
| 2026-09-24 00:00 |
22:03:56.34 |
-16:16:43.1 |
HIP 108918 |
22.05 |
| 2026-09-24 12:00 |
22:03:46.92 |
-16:17:16.2 |
HIP 108876 |
21.34 |
| 2026-09-25 00:00 |
22:03:37.61 |
-16:17:48.5 |
HIP 108876 |
20.24 |
| 2026-09-25 12:00 |
22:03:28.40 |
-16:18:20.1 |
HIP 108876 |
19.37 |
| 2026-09-26 00:00 |
22:03:19.30 |
-16:18:50.9 |
HIP 108876 |
18.74 |
| 2026-09-26 12:00 |
22:03:10.31 |
-16:19:21.0 |
HIP 108876 |
18.38 |
| 2026-09-27 00:00 |
22:03:01.42 |
-16:19:50.4 |
HIP 108876 |
18.28 |
| 2026-09-27 12:00 |
22:02:52.65 |
-16:20:19.1 |
HIP 108876 |
18.45 |
| 2026-09-28 00:00 |
22:02:43.99 |
-16:20:47.0 |
HIP 108876 |
18.86 |
| 2026-09-28 12:00 |
22:02:35.44 |
-16:21:14.1 |
HIP 108876 |
19.49 |
| 2026-09-29 00:00 |
22:02:27.01 |
-16:21:40.6 |
HIP 108876 |
20.32 |
| 2026-09-29 12:00 |
22:02:18.69 |
-16:22:06.2 |
HIP 108876 |
21.30 |
| 2026-09-30 00:00 |
22:02:10.48 |
-16:22:31.1 |
HIP 108876 |
22.41 |
| 2026-09-30 12:00 |
22:02:02.39 |
-16:22:55.3 |
HIP 108876 |
23.63 |
| 2026-10-01 00:00 |
22:01:54.43 |
-16:23:18.7 |
HIP 108876 |
24.93 |
| 2026-10-01 12:00 |
22:01:46.58 |
-16:23:41.3 |
HIP 108876 |
26.29 |
| 2026-10-02 00:00 |
22:01:38.84 |
-16:24:03.2 |
HIP 108876 |
27.70 |
| 2026-10-02 12:00 |
22:01:31.24 |
-16:24:24.3 |
HIP 108876 |
29.15 |
| 2026-10-03 00:00 |
22:01:23.75 |
-16:24:44.7 |
HIP 108876 |
30.61 |
| 2026-10-03 12:00 |
22:01:16.38 |
-16:25:04.2 |
HIP 108876 |
32.10 |
| 2026-10-04 00:00 |
22:01:09.14 |
-16:25:23.0 |
HIP 108876 |
33.59 |
| 2026-10-04 12:00 |
22:01:02.03 |
-16:25:41.1 |
HIP 108876 |
35.08 |
| 2026-10-05 00:00 |
22:00:55.04 |
-16:25:58.3 |
HIP 108876 |
36.56 |
| 2026-10-05 12:00 |
22:00:48.18 |
-16:26:14.8 |
HIP 108876 |
38.04 |
| 2026-10-06 00:00 |
22:00:41.45 |
-16:26:30.4 |
HIP 108876 |
39.51 |
| 2026-10-06 12:00 |
22:00:34.84 |
-16:26:45.3 |
HIP 108876 |
40.97 |
| 2026-10-07 00:00 |
22:00:28.37 |
-16:26:59.4 |
HIP 108797 |
41.85 |
| 2026-10-07 12:00 |
22:00:22.02 |
-16:27:12.7 |
HIP 108797 |
42.73 |
| 2026-10-08 00:00 |
22:00:15.81 |
-16:27:25.3 |
HIP 108797 |
43.63 |
| 2026-10-08 12:00 |
22:00:09.73 |
-16:27:37.0 |
HIP 108797 |
44.55 |
| 2026-10-09 00:00 |
22:00:03.78 |
-16:27:47.9 |
HIP 108797 |
45.49 |
| 2026-10-09 12:00 |
21:59:57.97 |
-16:27:58.0 |
HIP 108797 |
46.43 |
| 2026-10-10 00:00 |
21:59:52.29 |
-16:28:07.4 |
HIP 108797 |
47.38 |
| 2026-10-10 12:00 |
21:59:46.75 |
-16:28:15.9 |
HIP 108797 |
48.33 |
| 2026-10-11 00:00 |
21:59:41.35 |
-16:28:23.6 |
HIP 108358 |
48.11 |