C/2021 Q6 (PANSTARRS)
| Parameter |
Value |
| Designation |
C/2021 Q6 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2024-03-23T13:47:29.414400Z |
| Orbit solution date (soln_date, UTC) |
2025-09-16T12:42:41Z |
| Obs used |
388 |
| NEO |
- |
| M1 |
5.000 |
| K1 |
10.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-08-22T12:28:12.316800Z |
| Discovery magnitude (MPC) |
22.25 z |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2023-03-12.0000000 |
| e |
0.99972188 |
| q (au) |
8.709141 |
| a (au) |
31314.293105 |
| i (deg) |
161.847387 |
| Ω (om, deg) |
133.533757 |
| ω (w, deg) |
140.936211 |
| M (ma, deg) |
359.999933 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.982 + 4.541\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.982 |
| n |
4.541 |
| gf |
0.922 |
| gb |
-0.776 |
| k |
0.812 |
| δ90 |
7.756 |
| 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 |
21:17:26.79 |
-14:29:40.6 |
HIP 105042 |
23.24 |
| 2026-02-03 12:00 |
21:17:33.87 |
-14:29:32.3 |
HIP 105042 |
24.30 |
| 2026-02-04 00:00 |
21:17:40.95 |
-14:29:23.9 |
HIP 105042 |
25.44 |
| 2026-02-04 12:00 |
21:17:48.03 |
-14:29:15.4 |
HIP 105287 |
26.29 |
| 2026-02-05 00:00 |
21:17:55.12 |
-14:29:06.9 |
HIP 105287 |
24.59 |
| 2026-02-05 12:00 |
21:18:02.20 |
-14:28:58.3 |
HIP 105287 |
22.90 |
| 2026-02-06 00:00 |
21:18:09.29 |
-14:28:49.6 |
HIP 105287 |
21.21 |
| 2026-02-06 12:00 |
21:18:16.37 |
-14:28:41.0 |
HIP 105287 |
19.52 |
| 2026-02-07 00:00 |
21:18:23.45 |
-14:28:32.2 |
HIP 105287 |
17.84 |
| 2026-02-07 12:00 |
21:18:30.53 |
-14:28:23.5 |
HIP 105287 |
16.17 |
| 2026-02-08 00:00 |
21:18:37.61 |
-14:28:14.7 |
HIP 105287 |
14.51 |
| 2026-02-08 12:00 |
21:18:44.68 |
-14:28:05.8 |
HIP 105287 |
12.87 |
| 2026-02-09 00:00 |
21:18:51.75 |
-14:27:57.0 |
HIP 105287 |
11.25 |
| 2026-02-09 12:00 |
21:18:58.81 |
-14:27:48.1 |
HIP 105287 |
9.67 |
| 2026-02-10 00:00 |
21:19:05.86 |
-14:27:39.2 |
HIP 105287 |
8.14 |
| 2026-02-10 12:00 |
21:19:12.91 |
-14:27:30.3 |
HIP 105287 |
6.70 |
| 2026-02-11 00:00 |
21:19:19.95 |
-14:27:21.3 |
HIP 105287 |
5.43 |
| 2026-02-11 12:00 |
21:19:26.99 |
-14:27:12.4 |
HIP 105287 |
4.46 |
| 2026-02-12 00:00 |
21:19:34.01 |
-14:27:03.4 |
HIP 105287 |
4.02 |
| 2026-02-12 12:00 |
21:19:41.03 |
-14:26:54.5 |
HIP 105287 |
4.27 |
| 2026-02-13 00:00 |
21:19:48.03 |
-14:26:45.5 |
HIP 105287 |
5.11 |
| 2026-02-13 12:00 |
21:19:55.02 |
-14:26:36.6 |
HIP 105287 |
6.31 |
| 2026-02-14 00:00 |
21:20:02.01 |
-14:26:27.6 |
HIP 105287 |
7.69 |
| 2026-02-14 12:00 |
21:20:08.97 |
-14:26:18.7 |
HIP 105287 |
9.18 |
| 2026-02-15 00:00 |
21:20:15.93 |
-14:26:09.8 |
HIP 105287 |
10.73 |
| 2026-02-15 12:00 |
21:20:22.87 |
-14:26:00.9 |
HIP 105287 |
12.31 |
| 2026-02-16 00:00 |
21:20:29.80 |
-14:25:52.1 |
HIP 105287 |
13.91 |
| 2026-02-16 12:00 |
21:20:36.71 |
-14:25:43.3 |
HIP 105287 |
15.53 |
| 2026-02-17 00:00 |
21:20:43.60 |
-14:25:34.5 |
HIP 105287 |
17.15 |
| 2026-02-17 12:00 |
21:20:50.48 |
-14:25:25.7 |
HIP 105287 |
18.78 |
| 2026-02-18 00:00 |
21:20:57.34 |
-14:25:17.0 |
HIP 105287 |
20.41 |
| 2026-02-18 12:00 |
21:21:04.18 |
-14:25:08.4 |
HIP 105287 |
22.05 |
| 2026-02-19 00:00 |
21:21:11.00 |
-14:24:59.8 |
HIP 105287 |
23.68 |
| 2026-02-19 12:00 |
21:21:17.81 |
-14:24:51.2 |
HIP 105287 |
25.31 |
| 2026-02-20 00:00 |
21:21:24.59 |
-14:24:42.8 |
HIP 105287 |
26.94 |
| 2026-02-20 12:00 |
21:21:31.35 |
-14:24:34.3 |
HIP 105287 |
28.57 |
| 2026-02-21 00:00 |
21:21:38.08 |
-14:24:26.0 |
HIP 105287 |
30.19 |
| 2026-02-21 12:00 |
21:21:44.80 |
-14:24:17.7 |
HIP 105287 |
31.81 |
| 2026-02-22 00:00 |
21:21:51.49 |
-14:24:09.5 |
HIP 105519 |
31.60 |
| 2026-02-22 12:00 |
21:21:58.16 |
-14:24:01.4 |
HIP 105519 |
31.47 |
| 2026-02-23 00:00 |
21:22:04.80 |
-14:23:53.4 |
HIP 105519 |
31.41 |
| 2026-02-23 12:00 |
21:22:11.41 |
-14:23:45.4 |
HIP 105519 |
31.44 |
| 2026-02-24 00:00 |
21:22:18.00 |
-14:23:37.6 |
HIP 105519 |
31.55 |