| Parameter |
Value |
| Designation |
P/2021 R5 (Rankin) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-01-11T23:34:59.966400Z |
| Orbit solution date (soln_date, UTC) |
2024-04-29T13:12:24Z |
| Obs used |
251 |
| NEO |
- |
| M1 |
7.200 |
| K1 |
18.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-09-09T06:52:28.416000Z |
| Discovery magnitude (MPC) |
19.34 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-10-17.0000000 |
| e |
0.30753521 |
| q (au) |
3.322719 |
| a (au) |
4.798394 |
| i (deg) |
7.852203 |
| Ω (om, deg) |
219.963779 |
| ω (w, deg) |
167.335702 |
| M (ma, deg) |
351.843709 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.398 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.398 |
| n |
6.000 |
| gf |
0.972 |
| gb |
-0.934 |
| k |
1.000 |
| δ90 |
9.634 |
| 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 |
12:02:55.82 |
-05:12:44.5 |
HIP 58797 |
18.83 |
| 2026-05-12 12:00 |
12:02:50.10 |
-05:11:33.5 |
HIP 58797 |
20.60 |
| 2026-05-13 00:00 |
12:02:44.52 |
-05:10:23.4 |
HIP 58797 |
22.34 |
| 2026-05-13 12:00 |
12:02:39.08 |
-05:09:14.2 |
HIP 58797 |
24.06 |
| 2026-05-14 00:00 |
12:02:33.79 |
-05:08:05.8 |
HIP 58797 |
25.76 |
| 2026-05-14 12:00 |
12:02:28.65 |
-05:06:58.3 |
HIP 58797 |
27.43 |
| 2026-05-15 00:00 |
12:02:23.65 |
-05:05:51.7 |
HIP 58569 |
26.28 |
| 2026-05-15 12:00 |
12:02:18.80 |
-05:04:46.0 |
HIP 58569 |
25.16 |
| 2026-05-16 00:00 |
12:02:14.10 |
-05:03:41.1 |
HIP 58569 |
24.13 |
| 2026-05-16 12:00 |
12:02:09.54 |
-05:02:37.2 |
HIP 58569 |
23.20 |
| 2026-05-17 00:00 |
12:02:05.13 |
-05:01:34.2 |
HIP 58569 |
22.37 |
| 2026-05-17 12:00 |
12:02:00.87 |
-05:00:32.1 |
HIP 58569 |
21.64 |
| 2026-05-18 00:00 |
12:01:56.76 |
-04:59:30.9 |
HIP 58569 |
21.02 |
| 2026-05-18 12:00 |
12:01:52.80 |
-04:58:30.6 |
HIP 58569 |
20.52 |
| 2026-05-19 00:00 |
12:01:48.99 |
-04:57:31.2 |
HIP 58569 |
20.12 |
| 2026-05-19 12:00 |
12:01:45.33 |
-04:56:32.8 |
HIP 58569 |
19.83 |
| 2026-05-20 00:00 |
12:01:41.81 |
-04:55:35.3 |
HIP 58569 |
19.66 |
| 2026-05-20 12:00 |
12:01:38.45 |
-04:54:38.7 |
HIP 58569 |
19.58 |
| 2026-05-21 00:00 |
12:01:35.24 |
-04:53:43.1 |
HIP 58569 |
19.60 |
| 2026-05-21 12:00 |
12:01:32.18 |
-04:52:48.5 |
HIP 58569 |
19.71 |
| 2026-05-22 00:00 |
12:01:29.26 |
-04:51:54.8 |
HIP 58569 |
19.91 |
| 2026-05-22 12:00 |
12:01:26.50 |
-04:51:02.0 |
HIP 58569 |
20.18 |
| 2026-05-23 00:00 |
12:01:23.89 |
-04:50:10.2 |
HIP 58569 |
20.51 |
| 2026-05-23 12:00 |
12:01:21.43 |
-04:49:19.3 |
HIP 58569 |
20.90 |
| 2026-05-24 00:00 |
12:01:19.12 |
-04:48:29.4 |
HIP 58558 |
20.20 |
| 2026-05-24 12:00 |
12:01:16.96 |
-04:47:40.5 |
HIP 58558 |
19.23 |
| 2026-05-25 00:00 |
12:01:14.95 |
-04:46:52.5 |
HIP 58558 |
18.30 |
| 2026-05-25 12:00 |
12:01:13.09 |
-04:46:05.5 |
HIP 58558 |
17.40 |
| 2026-05-26 00:00 |
12:01:11.38 |
-04:45:19.5 |
HIP 58558 |
16.54 |
| 2026-05-26 12:00 |
12:01:09.82 |
-04:44:34.4 |
HIP 58558 |
15.72 |
| 2026-05-27 00:00 |
12:01:08.41 |
-04:43:50.3 |
HIP 58558 |
14.94 |
| 2026-05-27 12:00 |
12:01:07.15 |
-04:43:07.2 |
HIP 58558 |
14.21 |
| 2026-05-28 00:00 |
12:01:06.04 |
-04:42:25.1 |
HIP 58558 |
13.51 |
| 2026-05-28 12:00 |
12:01:05.08 |
-04:41:43.9 |
HIP 58558 |
12.86 |
| 2026-05-29 00:00 |
12:01:04.27 |
-04:41:03.7 |
HIP 58558 |
12.26 |
| 2026-05-29 12:00 |
12:01:03.61 |
-04:40:24.4 |
HIP 58558 |
11.71 |
| 2026-05-30 00:00 |
12:01:03.10 |
-04:39:46.2 |
HIP 58558 |
11.21 |
| 2026-05-30 12:00 |
12:01:02.74 |
-04:39:08.9 |
HIP 58558 |
10.77 |
| 2026-05-31 00:00 |
12:01:02.52 |
-04:38:32.6 |
HIP 58558 |
10.39 |
| 2026-05-31 12:00 |
12:01:02.46 |
-04:37:57.3 |
HIP 58558 |
10.06 |
| 2026-06-01 00:00 |
12:01:02.54 |
-04:37:23.0 |
HIP 58558 |
9.81 |
| 2026-06-01 12:00 |
12:01:02.77 |
-04:36:49.6 |
HIP 58558 |
9.62 |
| 2026-06-02 00:00 |
12:01:03.15 |
-04:36:17.3 |
HIP 58558 |
9.50 |