P/2021 R5 (Rankin)
| 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) |
| 2026-02-03 00:00 |
12:37:44.74 |
-09:34:22.0 |
HIP 61606 |
6.17 |
| 2026-02-03 12:00 |
12:37:40.55 |
-09:34:07.4 |
HIP 61606 |
5.90 |
| 2026-02-04 00:00 |
12:37:36.21 |
-09:33:51.6 |
HIP 61606 |
5.82 |
| 2026-02-04 12:00 |
12:37:31.72 |
-09:33:34.8 |
HIP 61606 |
5.97 |
| 2026-02-05 00:00 |
12:37:27.06 |
-09:33:16.8 |
HIP 61606 |
6.35 |
| 2026-02-05 12:00 |
12:37:22.26 |
-09:32:57.7 |
HIP 61606 |
6.94 |
| 2026-02-06 00:00 |
12:37:17.29 |
-09:32:37.5 |
HIP 61606 |
7.72 |
| 2026-02-06 12:00 |
12:37:12.17 |
-09:32:16.2 |
HIP 61606 |
8.65 |
| 2026-02-07 00:00 |
12:37:06.90 |
-09:31:53.8 |
HIP 61606 |
9.71 |
| 2026-02-07 12:00 |
12:37:01.48 |
-09:31:30.2 |
HIP 61606 |
10.87 |
| 2026-02-08 00:00 |
12:36:55.90 |
-09:31:05.6 |
HIP 61606 |
12.13 |
| 2026-02-08 12:00 |
12:36:50.17 |
-09:30:39.8 |
HIP 61606 |
13.46 |
| 2026-02-09 00:00 |
12:36:44.28 |
-09:30:12.9 |
HIP 61606 |
14.85 |
| 2026-02-09 12:00 |
12:36:38.25 |
-09:29:44.8 |
HIP 61606 |
16.32 |
| 2026-02-10 00:00 |
12:36:32.06 |
-09:29:15.7 |
HIP 61606 |
17.83 |
| 2026-02-10 12:00 |
12:36:25.72 |
-09:28:45.4 |
HIP 61606 |
19.41 |
| 2026-02-11 00:00 |
12:36:19.24 |
-09:28:14.1 |
HIP 61606 |
21.03 |
| 2026-02-11 12:00 |
12:36:12.60 |
-09:27:41.6 |
HIP 61606 |
22.71 |
| 2026-02-12 00:00 |
12:36:05.82 |
-09:27:08.0 |
HIP 61485 |
24.04 |
| 2026-02-12 12:00 |
12:35:58.89 |
-09:26:33.3 |
HIP 61485 |
23.29 |
| 2026-02-13 00:00 |
12:35:51.82 |
-09:25:57.5 |
HIP 61485 |
22.64 |
| 2026-02-13 12:00 |
12:35:44.59 |
-09:25:20.6 |
HIP 61485 |
22.11 |
| 2026-02-14 00:00 |
12:35:37.23 |
-09:24:42.5 |
HIP 61360 |
21.19 |
| 2026-02-14 12:00 |
12:35:29.72 |
-09:24:03.4 |
HIP 61360 |
20.04 |
| 2026-02-15 00:00 |
12:35:22.07 |
-09:23:23.2 |
HIP 61360 |
19.00 |
| 2026-02-15 12:00 |
12:35:14.27 |
-09:22:41.9 |
HIP 61360 |
18.12 |
| 2026-02-16 00:00 |
12:35:06.34 |
-09:21:59.5 |
HIP 61360 |
17.43 |
| 2026-02-16 12:00 |
12:34:58.27 |
-09:21:16.0 |
HIP 61360 |
16.96 |
| 2026-02-17 00:00 |
12:34:50.05 |
-09:20:31.4 |
HIP 61360 |
16.76 |
| 2026-02-17 12:00 |
12:34:41.71 |
-09:19:45.7 |
HIP 61318 |
15.42 |
| 2026-02-18 00:00 |
12:34:33.22 |
-09:18:59.0 |
HIP 61318 |
14.05 |
| 2026-02-18 12:00 |
12:34:24.60 |
-09:18:11.2 |
HIP 61318 |
12.92 |
| 2026-02-19 00:00 |
12:34:15.85 |
-09:17:22.3 |
HIP 61318 |
12.10 |
| 2026-02-19 12:00 |
12:34:06.96 |
-09:16:32.3 |
HIP 61318 |
11.70 |
| 2026-02-20 00:00 |
12:33:57.95 |
-09:15:41.3 |
HIP 61318 |
11.76 |
| 2026-02-20 12:00 |
12:33:48.80 |
-09:14:49.3 |
HIP 61318 |
12.31 |
| 2026-02-21 00:00 |
12:33:39.53 |
-09:13:56.2 |
HIP 61318 |
13.31 |
| 2026-02-21 12:00 |
12:33:30.13 |
-09:13:02.0 |
HIP 61318 |
14.68 |
| 2026-02-22 00:00 |
12:33:20.60 |
-09:12:06.9 |
HIP 61318 |
16.34 |
| 2026-02-22 12:00 |
12:33:10.95 |
-09:11:10.7 |
HIP 61318 |
18.23 |
| 2026-02-23 00:00 |
12:33:01.18 |
-09:10:13.5 |
HIP 61318 |
20.30 |
| 2026-02-23 12:00 |
12:32:51.29 |
-09:09:15.2 |
HIP 61108 |
21.28 |
| 2026-02-24 00:00 |
12:32:41.27 |
-09:08:16.0 |
HIP 61108 |
18.92 |