| 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 · 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
$$
M_a = (16.369 + 2.943\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.369 |
| n |
2.943 |
| gf |
0.970 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
9.997 |
| 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) |
| 2026-05-12 00:00 |
11:04:34.80 |
-08:45:53.5 |
HIP 54078 |
21.13 |
| 2026-05-12 12:00 |
11:04:31.76 |
-08:45:02.0 |
HIP 54078 |
21.59 |
| 2026-05-13 00:00 |
11:04:28.83 |
-08:44:11.1 |
HIP 54078 |
22.11 |
| 2026-05-13 12:00 |
11:04:26.02 |
-08:43:20.8 |
HIP 54078 |
22.67 |
| 2026-05-14 00:00 |
11:04:23.33 |
-08:42:31.0 |
HIP 54078 |
23.26 |
| 2026-05-14 12:00 |
11:04:20.76 |
-08:41:41.8 |
HIP 54078 |
23.89 |
| 2026-05-15 00:00 |
11:04:18.30 |
-08:40:53.2 |
HIP 54078 |
24.54 |
| 2026-05-15 12:00 |
11:04:15.95 |
-08:40:05.2 |
HIP 54015 |
25.02 |
| 2026-05-16 00:00 |
11:04:13.73 |
-08:39:17.8 |
HIP 54015 |
24.09 |
| 2026-05-16 12:00 |
11:04:11.62 |
-08:38:31.0 |
HIP 54015 |
23.18 |
| 2026-05-17 00:00 |
11:04:09.63 |
-08:37:44.8 |
HIP 54015 |
22.31 |
| 2026-05-17 12:00 |
11:04:07.75 |
-08:36:59.2 |
HIP 54015 |
21.47 |
| 2026-05-18 00:00 |
11:04:06.00 |
-08:36:14.3 |
HIP 54015 |
20.66 |
| 2026-05-18 12:00 |
11:04:04.36 |
-08:35:30.0 |
HIP 54015 |
19.89 |
| 2026-05-19 00:00 |
11:04:02.83 |
-08:34:46.3 |
HIP 54015 |
19.15 |
| 2026-05-19 12:00 |
11:04:01.42 |
-08:34:03.2 |
HIP 54015 |
18.44 |
| 2026-05-20 00:00 |
11:04:00.13 |
-08:33:20.8 |
HIP 54015 |
17.78 |
| 2026-05-20 12:00 |
11:03:58.96 |
-08:32:39.0 |
HIP 54015 |
17.15 |
| 2026-05-21 00:00 |
11:03:57.90 |
-08:31:57.8 |
HIP 54015 |
16.57 |
| 2026-05-21 12:00 |
11:03:56.96 |
-08:31:17.3 |
HIP 54015 |
16.03 |
| 2026-05-22 00:00 |
11:03:56.13 |
-08:30:37.5 |
HIP 54015 |
15.53 |
| 2026-05-22 12:00 |
11:03:55.42 |
-08:29:58.3 |
HIP 54015 |
15.08 |
| 2026-05-23 00:00 |
11:03:54.82 |
-08:29:19.8 |
HIP 54015 |
14.67 |
| 2026-05-23 12:00 |
11:03:54.34 |
-08:28:41.9 |
HIP 54015 |
14.32 |
| 2026-05-24 00:00 |
11:03:53.97 |
-08:28:04.7 |
HIP 54015 |
14.02 |
| 2026-05-24 12:00 |
11:03:53.72 |
-08:27:28.1 |
HIP 54015 |
13.77 |
| 2026-05-25 00:00 |
11:03:53.58 |
-08:26:52.3 |
HIP 54015 |
13.57 |
| 2026-05-25 12:00 |
11:03:53.56 |
-08:26:17.1 |
HIP 54015 |
13.42 |
| 2026-05-26 00:00 |
11:03:53.65 |
-08:25:42.5 |
HIP 54015 |
13.33 |
| 2026-05-26 12:00 |
11:03:53.85 |
-08:25:08.7 |
HIP 54015 |
13.30 |
| 2026-05-27 00:00 |
11:03:54.17 |
-08:24:35.5 |
HIP 54015 |
13.31 |
| 2026-05-27 12:00 |
11:03:54.60 |
-08:24:03.0 |
HIP 54015 |
13.38 |
| 2026-05-28 00:00 |
11:03:55.14 |
-08:23:31.2 |
HIP 54015 |
13.50 |
| 2026-05-28 12:00 |
11:03:55.80 |
-08:23:00.1 |
HIP 54015 |
13.67 |
| 2026-05-29 00:00 |
11:03:56.56 |
-08:22:29.6 |
HIP 54015 |
13.88 |
| 2026-05-29 12:00 |
11:03:57.44 |
-08:21:59.9 |
HIP 54015 |
14.14 |
| 2026-05-30 00:00 |
11:03:58.43 |
-08:21:30.8 |
HIP 54015 |
14.44 |
| 2026-05-30 12:00 |
11:03:59.53 |
-08:21:02.4 |
HIP 54015 |
14.78 |
| 2026-05-31 00:00 |
11:04:00.75 |
-08:20:34.8 |
HIP 54015 |
15.15 |
| 2026-05-31 12:00 |
11:04:02.07 |
-08:20:07.8 |
HIP 54015 |
15.56 |
| 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 |