| Parameter |
Value |
| Designation |
C/2021 V1 (Rankin) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-04-30T08:37:20.375040Z |
| Orbit solution date (soln_date, UTC) |
2022-02-14T01:12:42Z |
| Obs used |
67 |
| NEO |
- |
| M1 |
15.900 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-11-05T03:51:31.478400Z |
| Discovery magnitude (MPC) |
20.97 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-11-16.0000000 |
| e |
0.99556441 |
| q (au) |
3.013528 |
| a (au) |
679.397411 |
| i (deg) |
71.440704 |
| Ω (om, deg) |
207.653208 |
| ω (w, deg) |
195.103041 |
| M (ma, deg) |
359.990797 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.742 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.742 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-0.811 |
| 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) |
| 2026-07-29 00:00 |
11:05:09.70 |
-37:48:33.4 |
HIP 54170 |
7.18 |
| 2026-07-29 12:00 |
11:05:20.18 |
-37:47:52.1 |
HIP 54170 |
7.85 |
| 2026-07-30 00:00 |
11:05:30.69 |
-37:47:11.6 |
HIP 54170 |
9.03 |
| 2026-07-30 12:00 |
11:05:41.24 |
-37:46:31.9 |
HIP 54247 |
9.45 |
| 2026-07-31 00:00 |
11:05:51.83 |
-37:45:53.0 |
HIP 54247 |
9.86 |
| 2026-07-31 12:00 |
11:06:02.46 |
-37:45:15.0 |
HIP 54247 |
10.69 |
| 2026-08-01 00:00 |
11:06:13.12 |
-37:44:37.8 |
HIP 54247 |
11.87 |
| 2026-08-01 12:00 |
11:06:23.83 |
-37:44:01.4 |
HIP 54247 |
13.29 |
| 2026-08-02 00:00 |
11:06:34.57 |
-37:43:25.8 |
HIP 54247 |
14.90 |
| 2026-08-02 12:00 |
11:06:45.34 |
-37:42:51.0 |
HIP 54247 |
16.64 |
| 2026-08-03 00:00 |
11:06:56.15 |
-37:42:17.0 |
HIP 54247 |
18.48 |
| 2026-08-03 12:00 |
11:07:07.00 |
-37:41:43.9 |
HIP 54247 |
20.38 |
| 2026-08-04 00:00 |
11:07:17.88 |
-37:41:11.5 |
HIP 54247 |
22.34 |
| 2026-08-04 12:00 |
11:07:28.79 |
-37:40:40.0 |
HIP 54247 |
24.34 |
| 2026-08-05 00:00 |
11:07:39.74 |
-37:40:09.3 |
HIP 54247 |
26.37 |
| 2026-08-05 12:00 |
11:07:50.72 |
-37:39:39.4 |
HIP 54247 |
28.43 |
| 2026-08-06 00:00 |
11:08:01.74 |
-37:39:10.3 |
HIP 54247 |
30.51 |
| 2026-08-06 12:00 |
11:08:12.79 |
-37:38:42.0 |
HIP 54247 |
32.61 |
| 2026-08-07 00:00 |
11:08:23.87 |
-37:38:14.5 |
HIP 54575 |
34.41 |
| 2026-08-07 12:00 |
11:08:34.98 |
-37:37:47.9 |
HIP 54575 |
33.57 |
| 2026-08-08 00:00 |
11:08:46.12 |
-37:37:22.0 |
HIP 54575 |
32.84 |
| 2026-08-08 12:00 |
11:08:57.29 |
-37:36:57.0 |
HIP 54575 |
32.23 |
| 2026-08-09 00:00 |
11:09:08.49 |
-37:36:32.8 |
HIP 54575 |
31.76 |
| 2026-08-09 12:00 |
11:09:19.72 |
-37:36:09.3 |
HIP 54575 |
31.43 |
| 2026-08-10 00:00 |
11:09:30.98 |
-37:35:46.7 |
HIP 54575 |
31.24 |
| 2026-08-10 12:00 |
11:09:42.27 |
-37:35:24.9 |
HIP 54724 |
29.96 |
| 2026-08-11 00:00 |
11:09:53.58 |
-37:35:03.9 |
HIP 54724 |
27.71 |
| 2026-08-11 12:00 |
11:10:04.92 |
-37:34:43.7 |
HIP 54724 |
25.46 |
| 2026-08-12 00:00 |
11:10:16.29 |
-37:34:24.3 |
HIP 54724 |
23.21 |
| 2026-08-12 12:00 |
11:10:27.69 |
-37:34:05.7 |
HIP 54724 |
20.96 |
| 2026-08-13 00:00 |
11:10:39.11 |
-37:33:47.9 |
HIP 54724 |
18.71 |
| 2026-08-13 12:00 |
11:10:50.56 |
-37:33:30.9 |
HIP 54724 |
16.46 |
| 2026-08-14 00:00 |
11:11:02.03 |
-37:33:14.7 |
HIP 54724 |
14.22 |
| 2026-08-14 12:00 |
11:11:13.52 |
-37:32:59.3 |
HIP 54724 |
11.99 |
| 2026-08-15 00:00 |
11:11:25.04 |
-37:32:44.7 |
HIP 54724 |
9.78 |
| 2026-08-15 12:00 |
11:11:36.58 |
-37:32:30.9 |
HIP 54724 |
7.61 |
| 2026-08-16 00:00 |
11:11:48.14 |
-37:32:17.8 |
HIP 54724 |
5.53 |
| 2026-08-16 12:00 |
11:11:59.72 |
-37:32:05.6 |
HIP 54724 |
3.72 |
| 2026-08-17 00:00 |
11:12:11.32 |
-37:31:54.1 |
HIP 54724 |
2.76 |
| 2026-08-17 12:00 |
11:12:22.95 |
-37:31:43.4 |
HIP 54724 |
3.47 |
| 2026-08-18 00:00 |
11:12:34.59 |
-37:31:33.5 |
HIP 54724 |
5.20 |
| 2026-08-18 12:00 |
11:12:46.26 |
-37:31:24.4 |
HIP 54724 |
7.26 |
| 2026-08-19 00:00 |
11:12:57.94 |
-37:31:16.1 |
HIP 54761 |
8.84 |