C/2021 K3 (Catalina)
| Parameter |
Value |
| Designation |
C/2021 K3 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-02-02T08:11:00.119040Z |
| Orbit solution date (soln_date, UTC) |
2022-06-07T21:45:11Z |
| Obs used |
99 |
| NEO |
- |
| M1 |
14.500 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-07-16.0000000 |
| e |
1.00356145 |
| q (au) |
5.230100 |
| a (au) |
-1468.531415 |
| i (deg) |
134.804408 |
| Ω (om, deg) |
114.441510 |
| ω (w, deg) |
181.948465 |
| M (ma, deg) |
-0.003526 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.424 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.424 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.757 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
11:43:28.12 |
-50:17:05.7 |
HIP 57010 |
21.30 |
| 2026-02-03 12:00 |
11:43:12.30 |
-50:17:31.6 |
HIP 57010 |
18.96 |
| 2026-02-04 00:00 |
11:42:56.37 |
-50:17:56.2 |
HIP 57010 |
16.66 |
| 2026-02-04 12:00 |
11:42:40.34 |
-50:18:19.7 |
HIP 57010 |
14.45 |
| 2026-02-05 00:00 |
11:42:24.21 |
-50:18:41.9 |
HIP 57010 |
12.35 |
| 2026-02-05 12:00 |
11:42:07.97 |
-50:19:03.0 |
HIP 57010 |
10.46 |
| 2026-02-06 00:00 |
11:41:51.64 |
-50:19:22.8 |
HIP 57010 |
8.92 |
| 2026-02-06 12:00 |
11:41:35.21 |
-50:19:41.4 |
HIP 57010 |
7.95 |
| 2026-02-07 00:00 |
11:41:18.69 |
-50:19:58.7 |
HIP 57010 |
7.78 |
| 2026-02-07 12:00 |
11:41:02.07 |
-50:20:14.8 |
HIP 57010 |
8.46 |
| 2026-02-08 00:00 |
11:40:45.36 |
-50:20:29.7 |
HIP 57010 |
9.84 |
| 2026-02-08 12:00 |
11:40:28.55 |
-50:20:43.3 |
HIP 56904 |
10.10 |
| 2026-02-09 00:00 |
11:40:11.65 |
-50:20:55.6 |
HIP 56904 |
8.72 |
| 2026-02-09 12:00 |
11:39:54.66 |
-50:21:06.6 |
HIP 56904 |
8.05 |
| 2026-02-10 00:00 |
11:39:37.59 |
-50:21:16.4 |
HIP 56904 |
8.29 |
| 2026-02-10 12:00 |
11:39:20.43 |
-50:21:24.9 |
HIP 56904 |
9.38 |
| 2026-02-11 00:00 |
11:39:03.18 |
-50:21:32.1 |
HIP 56904 |
11.08 |
| 2026-02-11 12:00 |
11:38:45.84 |
-50:21:37.9 |
HIP 56776 |
10.22 |
| 2026-02-12 00:00 |
11:38:28.43 |
-50:21:42.5 |
HIP 56776 |
9.74 |
| 2026-02-12 12:00 |
11:38:10.93 |
-50:21:45.8 |
HIP 56776 |
10.01 |
| 2026-02-13 00:00 |
11:37:53.36 |
-50:21:47.7 |
HIP 56776 |
11.00 |
| 2026-02-13 12:00 |
11:37:35.70 |
-50:21:48.3 |
HIP 56714 |
12.39 |
| 2026-02-14 00:00 |
11:37:17.97 |
-50:21:47.6 |
HIP 56714 |
12.90 |
| 2026-02-14 12:00 |
11:37:00.17 |
-50:21:45.5 |
HIP 56714 |
14.00 |
| 2026-02-15 00:00 |
11:36:42.29 |
-50:21:42.1 |
HIP 56714 |
15.57 |
| 2026-02-15 12:00 |
11:36:24.34 |
-50:21:37.4 |
HIP 56714 |
17.49 |
| 2026-02-16 00:00 |
11:36:06.32 |
-50:21:31.2 |
HIP 56714 |
19.66 |
| 2026-02-16 12:00 |
11:35:48.23 |
-50:21:23.8 |
HIP 56714 |
22.01 |
| 2026-02-17 00:00 |
11:35:30.08 |
-50:21:15.0 |
HIP 56543 |
22.19 |
| 2026-02-17 12:00 |
11:35:11.86 |
-50:21:04.8 |
HIP 56430 |
20.84 |
| 2026-02-18 00:00 |
11:34:53.57 |
-50:20:53.2 |
HIP 56430 |
19.47 |
| 2026-02-18 12:00 |
11:34:35.23 |
-50:20:40.3 |
HIP 56430 |
18.45 |
| 2026-02-19 00:00 |
11:34:16.82 |
-50:20:25.9 |
HIP 56430 |
17.83 |
| 2026-02-19 12:00 |
11:33:58.36 |
-50:20:10.2 |
HIP 56430 |
17.67 |
| 2026-02-20 00:00 |
11:33:39.85 |
-50:19:53.1 |
HIP 56430 |
17.98 |
| 2026-02-20 12:00 |
11:33:21.27 |
-50:19:34.7 |
HIP 56430 |
18.76 |
| 2026-02-21 00:00 |
11:33:02.65 |
-50:19:14.8 |
HIP 56430 |
19.93 |
| 2026-02-21 12:00 |
11:32:43.98 |
-50:18:53.6 |
HIP 56430 |
21.46 |
| 2026-02-22 00:00 |
11:32:25.25 |
-50:18:30.9 |
HIP 56151 |
21.15 |
| 2026-02-22 12:00 |
11:32:06.48 |
-50:18:06.9 |
HIP 56151 |
18.97 |
| 2026-02-23 00:00 |
11:31:47.67 |
-50:17:41.5 |
HIP 56151 |
17.05 |
| 2026-02-23 12:00 |
11:31:28.81 |
-50:17:14.6 |
HIP 56151 |
15.51 |
| 2026-02-24 00:00 |
11:31:09.91 |
-50:16:46.4 |
HIP 56151 |
14.48 |