| Parameter |
Value |
| Designation |
P/2021 U1 (Wierzchos) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-09-30T23:25:09.215040Z |
| Orbit solution date (soln_date, UTC) |
2022-03-08T19:43:48Z |
| Obs used |
239 |
| NEO |
- |
| M1 |
16.000 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-10-18T08:26:24.028800Z |
| Discovery magnitude (MPC) |
19.17 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-11-26.0000000 |
| e |
0.71275870 |
| q (au) |
2.444983 |
| a (au) |
8.511949 |
| i (deg) |
30.560647 |
| Ω (om, deg) |
246.789455 |
| ω (w, deg) |
145.044255 |
| M (ma, deg) |
2.223495 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.832 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.832 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-25 00:00 |
11:28:35.74 |
-24:31:46.1 |
HIP 56078 |
14.84 |
| 2026-09-25 12:00 |
11:28:47.95 |
-24:33:00.1 |
HIP 56078 |
12.63 |
| 2026-09-26 00:00 |
11:29:00.14 |
-24:34:14.6 |
HIP 56078 |
10.85 |
| 2026-09-26 12:00 |
11:29:12.32 |
-24:35:29.4 |
HIP 56078 |
9.71 |
| 2026-09-27 00:00 |
11:29:24.48 |
-24:36:44.7 |
HIP 56078 |
9.47 |
| 2026-09-27 12:00 |
11:29:36.62 |
-24:38:00.4 |
HIP 56078 |
10.17 |
| 2026-09-28 00:00 |
11:29:48.75 |
-24:39:16.5 |
HIP 56078 |
11.66 |
| 2026-09-28 12:00 |
11:30:00.86 |
-24:40:33.1 |
HIP 56078 |
13.67 |
| 2026-09-29 00:00 |
11:30:12.95 |
-24:41:50.1 |
HIP 56078 |
16.02 |
| 2026-09-29 12:00 |
11:30:25.02 |
-24:43:07.4 |
HIP 56078 |
18.56 |
| 2026-09-30 00:00 |
11:30:37.07 |
-24:44:25.2 |
HIP 56085 |
19.60 |
| 2026-09-30 12:00 |
11:30:49.10 |
-24:45:43.4 |
HIP 56248 |
19.02 |
| 2026-10-01 00:00 |
11:31:01.11 |
-24:47:02.0 |
HIP 56248 |
18.23 |
| 2026-10-01 12:00 |
11:31:13.10 |
-24:48:21.1 |
HIP 56248 |
17.92 |
| 2026-10-02 00:00 |
11:31:25.07 |
-24:49:40.5 |
HIP 56248 |
18.13 |
| 2026-10-02 12:00 |
11:31:37.02 |
-24:51:00.3 |
HIP 56248 |
18.84 |
| 2026-10-03 00:00 |
11:31:48.94 |
-24:52:20.4 |
HIP 56248 |
19.99 |
| 2026-10-03 12:00 |
11:32:00.85 |
-24:53:41.0 |
HIP 56248 |
21.51 |
| 2026-10-04 00:00 |
11:32:12.73 |
-24:55:02.0 |
HIP 56248 |
23.33 |
| 2026-10-04 12:00 |
11:32:24.58 |
-24:56:23.3 |
HIP 56248 |
25.39 |
| 2026-10-05 00:00 |
11:32:36.41 |
-24:57:45.1 |
HIP 56248 |
27.62 |
| 2026-10-05 12:00 |
11:32:48.21 |
-24:59:07.2 |
HIP 56248 |
29.99 |
| 2026-10-06 00:00 |
11:33:00.00 |
-25:00:29.6 |
HIP 56451 |
27.14 |
| 2026-10-06 12:00 |
11:33:11.75 |
-25:01:52.5 |
HIP 56451 |
24.26 |
| 2026-10-07 00:00 |
11:33:23.47 |
-25:03:15.7 |
HIP 56451 |
21.41 |
| 2026-10-07 12:00 |
11:33:35.17 |
-25:04:39.2 |
HIP 56451 |
18.61 |
| 2026-10-08 00:00 |
11:33:46.84 |
-25:06:03.1 |
HIP 56451 |
15.88 |
| 2026-10-08 12:00 |
11:33:58.48 |
-25:07:27.4 |
HIP 56451 |
13.26 |
| 2026-10-09 00:00 |
11:34:10.10 |
-25:08:52.0 |
HIP 56451 |
10.82 |
| 2026-10-09 12:00 |
11:34:21.68 |
-25:10:17.0 |
HIP 56451 |
8.72 |
| 2026-10-10 00:00 |
11:34:33.23 |
-25:11:42.3 |
HIP 56451 |
7.27 |
| 2026-10-10 12:00 |
11:34:44.76 |
-25:13:07.9 |
HIP 56451 |
6.86 |
| 2026-10-11 00:00 |
11:34:56.25 |
-25:14:33.9 |
HIP 56451 |
7.67 |
| 2026-10-11 12:00 |
11:35:07.71 |
-25:16:00.1 |
HIP 56451 |
9.38 |
| 2026-10-12 00:00 |
11:35:19.13 |
-25:17:26.7 |
HIP 56451 |
11.60 |
| 2026-10-12 12:00 |
11:35:30.53 |
-25:18:53.7 |
HIP 56451 |
14.08 |
| 2026-10-13 00:00 |
11:35:41.89 |
-25:20:20.9 |
HIP 56451 |
16.71 |
| 2026-10-13 12:00 |
11:35:53.21 |
-25:21:48.4 |
HIP 56600 |
16.09 |
| 2026-10-14 00:00 |
11:36:04.50 |
-25:23:16.3 |
HIP 56600 |
14.01 |
| 2026-10-14 12:00 |
11:36:15.76 |
-25:24:44.4 |
HIP 56600 |
12.29 |
| 2026-10-15 00:00 |
11:36:26.98 |
-25:26:12.9 |
HIP 56600 |
11.07 |
| 2026-10-15 12:00 |
11:36:38.16 |
-25:27:41.6 |
HIP 56600 |
10.55 |
| 2026-10-16 00:00 |
11:36:49.31 |
-25:29:10.6 |
HIP 56600 |
10.80 |