| Parameter |
Value |
| Designation |
C/2021 U5 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-01-26T14:41:49.295040Z |
| Orbit solution date (soln_date, UTC) |
2022-11-29T21:43:26Z |
| Obs used |
463 |
| NEO |
- |
| M1 |
4.800 |
| K1 |
28.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-10-29T11:47:30.652800Z |
| Discovery magnitude (MPC) |
19.16 G |
| Discovery observatory (MPC) |
703 · University of Arizona Catalina Sky Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-02-19.0000000 |
| e |
0.98911516 |
| q (au) |
2.363288 |
| a (au) |
217.117490 |
| i (deg) |
39.049400 |
| Ω (om, deg) |
182.755199 |
| ω (w, deg) |
321.471259 |
| M (ma, deg) |
0.007205 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.219 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.219 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.744 |
| 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) |
| 2026-07-29 00:00 |
18:07:40.09 |
+18:03:32.7 |
HIP 88881 |
30.14 |
| 2026-07-29 12:00 |
18:07:33.83 |
+18:02:38.1 |
HIP 88881 |
30.14 |
| 2026-07-30 00:00 |
18:07:27.63 |
+18:01:42.9 |
HIP 88881 |
30.23 |
| 2026-07-30 12:00 |
18:07:21.47 |
+18:00:47.2 |
HIP 88881 |
30.40 |
| 2026-07-31 00:00 |
18:07:15.38 |
+17:59:50.8 |
HIP 88881 |
30.66 |
| 2026-07-31 12:00 |
18:07:09.33 |
+17:58:53.9 |
HIP 88881 |
30.99 |
| 2026-08-01 00:00 |
18:07:03.35 |
+17:57:56.5 |
HIP 88881 |
31.40 |
| 2026-08-01 12:00 |
18:06:57.41 |
+17:56:58.4 |
HIP 88881 |
31.88 |
| 2026-08-02 00:00 |
18:06:51.54 |
+17:55:59.9 |
HIP 88881 |
32.42 |
| 2026-08-02 12:00 |
18:06:45.72 |
+17:55:00.7 |
HIP 88881 |
33.03 |
| 2026-08-03 00:00 |
18:06:39.96 |
+17:54:01.0 |
HIP 88881 |
33.70 |
| 2026-08-03 12:00 |
18:06:34.26 |
+17:53:00.8 |
HIP 88881 |
34.42 |
| 2026-08-04 00:00 |
18:06:28.62 |
+17:52:00.0 |
HIP 88881 |
35.19 |
| 2026-08-04 12:00 |
18:06:23.04 |
+17:50:58.7 |
HIP 88881 |
36.01 |
| 2026-08-05 00:00 |
18:06:17.51 |
+17:49:56.9 |
HIP 88881 |
36.86 |
| 2026-08-05 12:00 |
18:06:12.05 |
+17:48:54.6 |
HIP 88881 |
37.76 |
| 2026-08-06 00:00 |
18:06:06.65 |
+17:47:51.7 |
HIP 88881 |
38.69 |
| 2026-08-06 12:00 |
18:06:01.31 |
+17:46:48.3 |
HIP 88881 |
39.66 |
| 2026-08-07 00:00 |
18:05:56.03 |
+17:45:44.5 |
HIP 88430 |
39.28 |
| 2026-08-07 12:00 |
18:05:50.81 |
+17:44:40.1 |
HIP 88430 |
37.83 |
| 2026-08-08 00:00 |
18:05:45.66 |
+17:43:35.2 |
HIP 88430 |
36.41 |
| 2026-08-08 12:00 |
18:05:40.56 |
+17:42:29.9 |
HIP 88430 |
35.02 |
| 2026-08-09 00:00 |
18:05:35.54 |
+17:41:24.1 |
HIP 88430 |
33.66 |
| 2026-08-09 12:00 |
18:05:30.57 |
+17:40:17.8 |
HIP 88430 |
32.35 |
| 2026-08-10 00:00 |
18:05:25.67 |
+17:39:11.0 |
HIP 88430 |
31.07 |
| 2026-08-10 12:00 |
18:05:20.84 |
+17:38:03.8 |
HIP 88430 |
29.85 |
| 2026-08-11 00:00 |
18:05:16.07 |
+17:36:56.1 |
HIP 88430 |
28.67 |
| 2026-08-11 12:00 |
18:05:11.37 |
+17:35:48.0 |
HIP 88430 |
27.56 |
| 2026-08-12 00:00 |
18:05:06.73 |
+17:34:39.4 |
HIP 88430 |
26.51 |
| 2026-08-12 12:00 |
18:05:02.16 |
+17:33:30.4 |
HIP 88430 |
25.53 |
| 2026-08-13 00:00 |
18:04:57.66 |
+17:32:20.9 |
HIP 88430 |
24.64 |
| 2026-08-13 12:00 |
18:04:53.23 |
+17:31:11.1 |
HIP 88430 |
23.83 |
| 2026-08-14 00:00 |
18:04:48.86 |
+17:30:00.8 |
HIP 88430 |
23.12 |
| 2026-08-14 12:00 |
18:04:44.57 |
+17:28:50.1 |
HIP 88430 |
22.51 |
| 2026-08-15 00:00 |
18:04:40.34 |
+17:27:39.1 |
HIP 88430 |
22.01 |
| 2026-08-15 12:00 |
18:04:36.18 |
+17:26:27.6 |
HIP 88430 |
21.63 |
| 2026-08-16 00:00 |
18:04:32.09 |
+17:25:15.7 |
HIP 88578 |
21.03 |
| 2026-08-16 12:00 |
18:04:28.07 |
+17:24:03.5 |
HIP 88578 |
20.40 |
| 2026-08-17 00:00 |
18:04:24.12 |
+17:22:50.9 |
HIP 88578 |
19.85 |
| 2026-08-17 12:00 |
18:04:20.24 |
+17:21:37.9 |
HIP 88578 |
19.40 |
| 2026-08-18 00:00 |
18:04:16.43 |
+17:20:24.6 |
HIP 88395 |
18.41 |
| 2026-08-18 12:00 |
18:04:12.70 |
+17:19:10.9 |
HIP 88395 |
17.31 |
| 2026-08-19 00:00 |
18:04:09.03 |
+17:17:56.9 |
HIP 88395 |
16.30 |