| 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) |
| 2026-05-12 00:00 |
21:27:34.45 |
-14:59:03.5 |
HIP 105997 |
11.51 |
| 2026-05-12 12:00 |
21:27:29.78 |
-14:59:51.4 |
HIP 105997 |
12.84 |
| 2026-05-13 00:00 |
21:27:24.99 |
-15:00:39.8 |
HIP 105997 |
14.20 |
| 2026-05-13 12:00 |
21:27:20.10 |
-15:01:28.8 |
HIP 105997 |
15.60 |
| 2026-05-14 00:00 |
21:27:15.09 |
-15:02:18.4 |
HIP 105861 |
16.98 |
| 2026-05-14 12:00 |
21:27:09.98 |
-15:03:08.5 |
HIP 105861 |
15.53 |
| 2026-05-15 00:00 |
21:27:04.76 |
-15:03:59.2 |
HIP 105861 |
14.06 |
| 2026-05-15 12:00 |
21:26:59.42 |
-15:04:50.4 |
HIP 105861 |
12.59 |
| 2026-05-16 00:00 |
21:26:53.98 |
-15:05:42.2 |
HIP 105861 |
11.11 |
| 2026-05-16 12:00 |
21:26:48.42 |
-15:06:34.6 |
HIP 105861 |
9.63 |
| 2026-05-17 00:00 |
21:26:42.76 |
-15:07:27.5 |
HIP 105861 |
8.18 |
| 2026-05-17 12:00 |
21:26:36.98 |
-15:08:20.9 |
HIP 105861 |
6.80 |
| 2026-05-18 00:00 |
21:26:31.09 |
-15:09:15.0 |
HIP 105861 |
5.55 |
| 2026-05-18 12:00 |
21:26:25.09 |
-15:10:09.5 |
HIP 105861 |
4.58 |
| 2026-05-19 00:00 |
21:26:18.98 |
-15:11:04.6 |
HIP 105861 |
4.13 |
| 2026-05-19 12:00 |
21:26:12.75 |
-15:12:00.3 |
HIP 105861 |
4.39 |
| 2026-05-20 00:00 |
21:26:06.42 |
-15:12:56.6 |
HIP 105861 |
5.29 |
| 2026-05-20 12:00 |
21:25:59.97 |
-15:13:53.4 |
HIP 105861 |
6.59 |
| 2026-05-21 00:00 |
21:25:53.42 |
-15:14:50.7 |
HIP 105861 |
8.12 |
| 2026-05-21 12:00 |
21:25:46.75 |
-15:15:48.6 |
HIP 105861 |
9.79 |
| 2026-05-22 00:00 |
21:25:39.96 |
-15:16:47.1 |
HIP 105861 |
11.55 |
| 2026-05-22 12:00 |
21:25:33.07 |
-15:17:46.1 |
HIP 105861 |
13.38 |
| 2026-05-23 00:00 |
21:25:26.07 |
-15:18:45.6 |
HIP 105861 |
15.26 |
| 2026-05-23 12:00 |
21:25:18.95 |
-15:19:45.7 |
HIP 105861 |
17.18 |
| 2026-05-24 00:00 |
21:25:11.72 |
-15:20:46.4 |
HIP 105861 |
19.15 |
| 2026-05-24 12:00 |
21:25:04.38 |
-15:21:47.6 |
HIP 105861 |
21.16 |
| 2026-05-25 00:00 |
21:24:56.93 |
-15:22:49.3 |
HIP 105861 |
23.20 |
| 2026-05-25 12:00 |
21:24:49.37 |
-15:23:51.6 |
HIP 105861 |
25.27 |
| 2026-05-26 00:00 |
21:24:41.69 |
-15:24:54.4 |
HIP 105861 |
27.37 |
| 2026-05-26 12:00 |
21:24:33.90 |
-15:25:57.8 |
HIP 105861 |
29.51 |
| 2026-05-27 00:00 |
21:24:26.01 |
-15:27:01.7 |
HIP 105861 |
31.68 |
| 2026-05-27 12:00 |
21:24:18.00 |
-15:28:06.1 |
HIP 105861 |
33.87 |
| 2026-05-28 00:00 |
21:24:09.88 |
-15:29:11.1 |
HIP 105684 |
34.65 |
| 2026-05-28 12:00 |
21:24:01.64 |
-15:30:16.6 |
HIP 105684 |
33.77 |
| 2026-05-29 00:00 |
21:23:53.30 |
-15:31:22.7 |
HIP 105684 |
33.02 |
| 2026-05-29 12:00 |
21:23:44.85 |
-15:32:29.3 |
HIP 105684 |
32.42 |
| 2026-05-30 00:00 |
21:23:36.28 |
-15:33:36.4 |
HIP 105684 |
31.97 |
| 2026-05-30 12:00 |
21:23:27.60 |
-15:34:44.0 |
HIP 105684 |
31.69 |
| 2026-05-31 00:00 |
21:23:18.82 |
-15:35:52.2 |
HIP 105474 |
31.53 |
| 2026-05-31 12:00 |
21:23:09.92 |
-15:37:00.9 |
HIP 105474 |
29.23 |
| 2026-06-01 00:00 |
21:23:00.91 |
-15:38:10.1 |
HIP 105474 |
26.93 |
| 2026-06-01 12:00 |
21:22:51.79 |
-15:39:19.9 |
HIP 105474 |
24.64 |
| 2026-06-02 00:00 |
21:22:42.56 |
-15:40:30.2 |
HIP 105474 |
22.37 |