| 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 · 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 |
1.000 |
| gb |
-0.803 |
| 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) |
| 2026-05-12 00:00 |
10:51:29.58 |
-42:06:09.3 |
HIP 53080 |
19.00 |
| 2026-05-12 12:00 |
10:51:27.86 |
-42:03:50.5 |
HIP 53080 |
16.71 |
| 2026-05-13 00:00 |
10:51:26.24 |
-42:01:31.8 |
HIP 53080 |
14.43 |
| 2026-05-13 12:00 |
10:51:24.73 |
-41:59:13.3 |
HIP 53080 |
12.17 |
| 2026-05-14 00:00 |
10:51:23.32 |
-41:56:54.9 |
HIP 53080 |
9.94 |
| 2026-05-14 12:00 |
10:51:22.03 |
-41:54:36.8 |
HIP 53080 |
7.77 |
| 2026-05-15 00:00 |
10:51:20.83 |
-41:52:18.7 |
HIP 53080 |
5.69 |
| 2026-05-15 12:00 |
10:51:19.75 |
-41:50:00.9 |
HIP 53080 |
3.88 |
| 2026-05-16 00:00 |
10:51:18.77 |
-41:47:43.3 |
HIP 53080 |
2.87 |
| 2026-05-16 12:00 |
10:51:17.90 |
-41:45:25.9 |
HIP 53080 |
3.45 |
| 2026-05-17 00:00 |
10:51:17.13 |
-41:43:08.7 |
HIP 53080 |
5.10 |
| 2026-05-17 12:00 |
10:51:16.47 |
-41:40:51.7 |
HIP 53080 |
7.09 |
| 2026-05-18 00:00 |
10:51:15.92 |
-41:38:35.0 |
HIP 53080 |
9.22 |
| 2026-05-18 12:00 |
10:51:15.47 |
-41:36:18.5 |
HIP 53080 |
11.39 |
| 2026-05-19 00:00 |
10:51:15.13 |
-41:34:02.3 |
HIP 53080 |
13.59 |
| 2026-05-19 12:00 |
10:51:14.89 |
-41:31:46.3 |
HIP 53080 |
15.80 |
| 2026-05-20 00:00 |
10:51:14.76 |
-41:29:30.6 |
HIP 53080 |
18.02 |
| 2026-05-20 12:00 |
10:51:14.73 |
-41:27:15.3 |
HIP 53080 |
20.23 |
| 2026-05-21 00:00 |
10:51:14.81 |
-41:25:00.2 |
HIP 53107 |
19.49 |
| 2026-05-21 12:00 |
10:51:14.99 |
-41:22:45.4 |
HIP 53107 |
17.42 |
| 2026-05-22 00:00 |
10:51:15.27 |
-41:20:31.0 |
HIP 53107 |
15.40 |
| 2026-05-22 12:00 |
10:51:15.66 |
-41:18:16.9 |
HIP 53107 |
13.44 |
| 2026-05-23 00:00 |
10:51:16.15 |
-41:16:03.1 |
HIP 53107 |
11.57 |
| 2026-05-23 12:00 |
10:51:16.75 |
-41:13:49.6 |
HIP 53107 |
9.85 |
| 2026-05-24 00:00 |
10:51:17.45 |
-41:11:36.6 |
HIP 53107 |
8.35 |
| 2026-05-24 12:00 |
10:51:18.25 |
-41:09:23.8 |
HIP 53107 |
7.22 |
| 2026-05-25 00:00 |
10:51:19.15 |
-41:07:11.5 |
HIP 53107 |
6.64 |
| 2026-05-25 12:00 |
10:51:20.15 |
-41:04:59.5 |
HIP 53107 |
6.75 |
| 2026-05-26 00:00 |
10:51:21.26 |
-41:02:47.9 |
HIP 53107 |
7.52 |
| 2026-05-26 12:00 |
10:51:22.46 |
-41:00:36.7 |
HIP 53107 |
8.77 |
| 2026-05-27 00:00 |
10:51:23.77 |
-40:58:25.9 |
HIP 53107 |
10.32 |
| 2026-05-27 12:00 |
10:51:25.17 |
-40:56:15.6 |
HIP 53107 |
12.06 |
| 2026-05-28 00:00 |
10:51:26.68 |
-40:54:05.6 |
HIP 53107 |
13.92 |
| 2026-05-28 12:00 |
10:51:28.29 |
-40:51:56.0 |
HIP 53107 |
15.84 |
| 2026-05-29 00:00 |
10:51:29.99 |
-40:49:46.9 |
HIP 53107 |
17.81 |
| 2026-05-29 12:00 |
10:51:31.80 |
-40:47:38.3 |
HIP 52971 |
19.50 |
| 2026-05-30 00:00 |
10:51:33.70 |
-40:45:30.0 |
HIP 52971 |
20.94 |
| 2026-05-30 12:00 |
10:51:35.70 |
-40:43:22.3 |
HIP 52971 |
22.51 |
| 2026-05-31 00:00 |
10:51:37.80 |
-40:41:14.9 |
HIP 53218 |
23.21 |
| 2026-05-31 12:00 |
10:51:39.99 |
-40:39:08.1 |
HIP 53218 |
21.47 |
| 2026-06-01 00:00 |
10:51:42.29 |
-40:37:01.7 |
HIP 53218 |
19.81 |
| 2026-06-01 12:00 |
10:51:44.68 |
-40:34:55.8 |
HIP 53218 |
18.24 |
| 2026-06-02 00:00 |
10:51:47.16 |
-40:32:50.4 |
HIP 53218 |
16.77 |