| Parameter |
Value |
| Designation |
425P/Kowalski |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-09-21T00:11:04.882560Z |
| Orbit solution date (soln_date, UTC) |
2024-02-01T00:43:56Z |
| Obs used |
427 |
| NEO |
- |
| M1 |
7.100 |
| K1 |
20.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-07-20T14:22:26.860800Z |
| Discovery magnitude (MPC) |
20.36 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-07-26.0000000 |
| e |
0.54240402 |
| q (au) |
2.901345 |
| a (au) |
6.340409 |
| i (deg) |
16.427088 |
| Ω (om, deg) |
210.335779 |
| ω (w, deg) |
200.221889 |
| M (ma, deg) |
266.286495 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.353 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.353 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.633 |
| k |
0.800 |
| 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 |
| 2020-08-19 |
2021-09-16 |
+11.9451 |
-5.152 |
| 2021-09-30 |
2023-01-25 |
-3.5885 |
+1.530 |
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 |
13:20:01.96 |
-11:45:05.2 |
HIP 65023 |
6.42 |
| 2026-03-26 12:00 |
13:19:51.56 |
-11:43:49.6 |
HIP 65023 |
3.90 |
| 2026-03-27 00:00 |
13:19:41.12 |
-11:42:33.6 |
HIP 65023 |
2.30 |
| 2026-03-27 12:00 |
13:19:30.65 |
-11:41:17.3 |
HIP 65023 |
3.42 |
| 2026-03-28 00:00 |
13:19:20.14 |
-11:40:00.6 |
HIP 65023 |
5.88 |
| 2026-03-28 12:00 |
13:19:09.59 |
-11:38:43.5 |
HIP 65023 |
8.61 |
| 2026-03-29 00:00 |
13:18:59.02 |
-11:37:26.1 |
HIP 65023 |
11.43 |
| 2026-03-29 12:00 |
13:18:48.41 |
-11:36:08.4 |
HIP 65023 |
14.28 |
| 2026-03-30 00:00 |
13:18:37.78 |
-11:34:50.3 |
HIP 65023 |
17.16 |
| 2026-03-30 12:00 |
13:18:27.11 |
-11:33:32.0 |
HIP 64828 |
16.57 |
| 2026-03-31 00:00 |
13:18:16.42 |
-11:32:13.3 |
HIP 64828 |
13.71 |
| 2026-03-31 12:00 |
13:18:05.71 |
-11:30:54.3 |
HIP 64828 |
10.87 |
| 2026-04-01 00:00 |
13:17:54.97 |
-11:29:35.0 |
HIP 64828 |
8.09 |
| 2026-04-01 12:00 |
13:17:44.20 |
-11:28:15.4 |
HIP 64828 |
5.49 |
| 2026-04-02 00:00 |
13:17:33.42 |
-11:26:55.5 |
HIP 64828 |
3.49 |
| 2026-04-02 12:00 |
13:17:22.61 |
-11:25:35.4 |
HIP 64828 |
3.43 |
| 2026-04-03 00:00 |
13:17:11.79 |
-11:24:15.0 |
HIP 64828 |
5.38 |
| 2026-04-03 12:00 |
13:17:00.95 |
-11:22:54.4 |
HIP 64828 |
8.00 |
| 2026-04-04 00:00 |
13:16:50.09 |
-11:21:33.5 |
HIP 64828 |
10.81 |
| 2026-04-04 12:00 |
13:16:39.22 |
-11:20:12.3 |
HIP 64828 |
13.70 |
| 2026-04-05 00:00 |
13:16:28.33 |
-11:18:51.0 |
HIP 64828 |
16.62 |
| 2026-04-05 12:00 |
13:16:17.44 |
-11:17:29.4 |
HIP 64643 |
19.08 |
| 2026-04-06 00:00 |
13:16:06.53 |
-11:16:07.6 |
HIP 64643 |
16.79 |
| 2026-04-06 12:00 |
13:15:55.62 |
-11:14:45.6 |
HIP 64643 |
14.76 |
| 2026-04-07 00:00 |
13:15:44.69 |
-11:13:23.4 |
HIP 64643 |
13.11 |
| 2026-04-07 12:00 |
13:15:33.76 |
-11:12:01.0 |
HIP 64643 |
12.00 |
| 2026-04-08 00:00 |
13:15:22.83 |
-11:10:38.4 |
HIP 64643 |
11.59 |
| 2026-04-08 12:00 |
13:15:11.89 |
-11:09:15.7 |
HIP 64643 |
11.95 |
| 2026-04-09 00:00 |
13:15:00.95 |
-11:07:52.8 |
HIP 64643 |
13.03 |
| 2026-04-09 12:00 |
13:14:50.01 |
-11:06:29.8 |
HIP 64643 |
14.66 |
| 2026-04-10 00:00 |
13:14:39.07 |
-11:05:06.6 |
HIP 64643 |
16.68 |
| 2026-04-10 12:00 |
13:14:28.13 |
-11:03:43.3 |
HIP 64643 |
18.97 |
| 2026-04-11 00:00 |
13:14:17.19 |
-11:02:19.9 |
HIP 64643 |
21.44 |
| 2026-04-11 12:00 |
13:14:06.27 |
-11:00:56.3 |
HIP 64643 |
24.04 |
| 2026-04-12 00:00 |
13:13:55.34 |
-10:59:32.7 |
HIP 64643 |
26.73 |
| 2026-04-12 12:00 |
13:13:44.43 |
-10:58:08.9 |
HIP 64643 |
29.49 |
| 2026-04-13 00:00 |
13:13:33.52 |
-10:56:45.1 |
HIP 64378 |
32.27 |
| 2026-04-13 12:00 |
13:13:22.63 |
-10:55:21.2 |
HIP 64378 |
30.80 |
| 2026-04-14 00:00 |
13:13:11.75 |
-10:53:57.2 |
HIP 64378 |
29.57 |
| 2026-04-14 12:00 |
13:13:00.88 |
-10:52:33.1 |
HIP 64378 |
28.61 |
| 2026-04-15 00:00 |
13:12:50.03 |
-10:51:09.1 |
HIP 64378 |
27.94 |
| 2026-04-15 12:00 |
13:12:39.19 |
-10:49:45.0 |
HIP 64378 |
27.59 |
| 2026-04-16 00:00 |
13:12:28.37 |
-10:48:20.8 |
HIP 64378 |
27.57 |