| Parameter |
Value |
| Designation |
P/2021 R4 (Wierzchos) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-10-13T22:05:15.889920Z |
| Orbit solution date (soln_date, UTC) |
2021-11-20T19:13:09Z |
| Obs used |
76 |
| NEO |
- |
| M1 |
16.300 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-09-06T09:39:32.976000Z |
| Discovery magnitude (MPC) |
21.16 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-09-24.0000000 |
| e |
0.58615107 |
| q (au) |
2.325993 |
| a (au) |
5.620391 |
| i (deg) |
21.040112 |
| Ω (om, deg) |
321.256290 |
| ω (w, deg) |
56.624470 |
| M (ma, deg) |
358.526498 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.933 + 3.415\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.933 |
| n |
3.415 |
| gf |
1.000 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
11:04:03.50 |
-08:19:41.5 |
HIP 54015 |
16.00 |
| 2026-06-01 12:00 |
11:04:05.04 |
-08:19:15.9 |
HIP 54015 |
16.48 |
| 2026-06-02 00:00 |
11:04:06.69 |
-08:18:51.0 |
HIP 54015 |
16.98 |
| 2026-06-02 12:00 |
11:04:08.46 |
-08:18:26.8 |
HIP 54015 |
17.51 |
| 2026-06-03 00:00 |
11:04:10.33 |
-08:18:03.4 |
HIP 54015 |
18.06 |
| 2026-06-03 12:00 |
11:04:12.31 |
-08:17:40.6 |
HIP 54015 |
18.65 |
| 2026-06-04 00:00 |
11:04:14.39 |
-08:17:18.5 |
HIP 54015 |
19.25 |
| 2026-06-04 12:00 |
11:04:16.59 |
-08:16:57.2 |
HIP 54015 |
19.88 |
| 2026-06-05 00:00 |
11:04:18.89 |
-08:16:36.5 |
HIP 54015 |
20.53 |
| 2026-06-05 12:00 |
11:04:21.30 |
-08:16:16.6 |
HIP 54015 |
21.20 |
| 2026-06-06 00:00 |
11:04:23.82 |
-08:15:57.4 |
HIP 54015 |
21.90 |
| 2026-06-06 12:00 |
11:04:26.45 |
-08:15:38.9 |
HIP 54015 |
22.61 |
| 2026-06-07 00:00 |
11:04:29.18 |
-08:15:21.1 |
HIP 54015 |
23.35 |
| 2026-06-07 12:00 |
11:04:32.01 |
-08:15:04.0 |
HIP 54015 |
24.11 |
| 2026-06-08 00:00 |
11:04:34.96 |
-08:14:47.6 |
HIP 54015 |
24.89 |
| 2026-06-08 12:00 |
11:04:38.01 |
-08:14:32.0 |
HIP 54015 |
25.68 |
| 2026-06-09 00:00 |
11:04:41.16 |
-08:14:17.1 |
HIP 54015 |
26.50 |
| 2026-06-09 12:00 |
11:04:44.42 |
-08:14:02.9 |
HIP 54015 |
27.34 |
| 2026-06-10 00:00 |
11:04:47.78 |
-08:13:49.4 |
HIP 54015 |
28.20 |
| 2026-06-10 12:00 |
11:04:51.25 |
-08:13:36.7 |
HIP 54015 |
29.08 |
| 2026-06-11 00:00 |
11:04:54.82 |
-08:13:24.7 |
HIP 54015 |
29.98 |
| 2026-06-11 12:00 |
11:04:58.50 |
-08:13:13.4 |
HIP 54015 |
30.90 |
| 2026-06-12 00:00 |
11:05:02.27 |
-08:13:02.9 |
HIP 54015 |
31.84 |
| 2026-06-12 12:00 |
11:05:06.16 |
-08:12:53.0 |
HIP 54015 |
32.80 |
| 2026-06-13 00:00 |
11:05:10.14 |
-08:12:44.0 |
HIP 54015 |
33.78 |
| 2026-06-13 12:00 |
11:05:14.22 |
-08:12:35.6 |
HIP 54015 |
34.79 |
| 2026-06-14 00:00 |
11:05:18.41 |
-08:12:28.0 |
HIP 54015 |
35.81 |
| 2026-06-14 12:00 |
11:05:22.70 |
-08:12:21.1 |
HIP 54015 |
36.86 |
| 2026-06-15 00:00 |
11:05:27.09 |
-08:12:15.0 |
HIP 54361 |
36.16 |
| 2026-06-15 12:00 |
11:05:31.58 |
-08:12:09.6 |
HIP 54361 |
35.39 |
| 2026-06-16 00:00 |
11:05:36.17 |
-08:12:04.9 |
HIP 54361 |
34.61 |
| 2026-06-16 12:00 |
11:05:40.86 |
-08:12:00.9 |
HIP 54361 |
33.83 |
| 2026-06-17 00:00 |
11:05:45.65 |
-08:11:57.7 |
HIP 54361 |
33.05 |
| 2026-06-17 12:00 |
11:05:50.53 |
-08:11:55.3 |
HIP 54361 |
32.26 |
| 2026-06-18 00:00 |
11:05:55.52 |
-08:11:53.5 |
HIP 54361 |
31.48 |
| 2026-06-18 12:00 |
11:06:00.60 |
-08:11:52.5 |
HIP 54361 |
30.70 |
| 2026-06-19 00:00 |
11:06:05.77 |
-08:11:52.3 |
HIP 54361 |
29.93 |
| 2026-06-19 12:00 |
11:06:11.05 |
-08:11:52.8 |
HIP 54361 |
29.18 |
| 2026-06-20 00:00 |
11:06:16.42 |
-08:11:54.0 |
HIP 54361 |
28.43 |
| 2026-06-20 12:00 |
11:06:21.88 |
-08:11:55.9 |
HIP 54361 |
27.72 |
| 2026-06-21 00:00 |
11:06:27.44 |
-08:11:58.6 |
HIP 54361 |
27.02 |
| 2026-06-21 12:00 |
11:06:33.10 |
-08:12:02.0 |
HIP 54361 |
26.37 |
| 2026-06-22 00:00 |
11:06:38.84 |
-08:12:06.1 |
HIP 54361 |
25.75 |