| 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
$$
M_a = (7.902 + 4.541\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.902 |
| n |
4.541 |
| gf |
0.875 |
| gb |
-0.776 |
| k |
0.823 |
| δ90 |
6.898 |
| 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) |
| 2026-09-20 00:00 |
20:26:38.64 |
-21:02:13.4 |
HIP 100740 |
18.04 |
| 2026-09-20 12:00 |
20:26:26.53 |
-21:03:14.2 |
HIP 100740 |
15.05 |
| 2026-09-21 00:00 |
20:26:14.53 |
-21:04:14.5 |
HIP 100740 |
12.08 |
| 2026-09-21 12:00 |
20:26:02.64 |
-21:05:14.3 |
HIP 100740 |
9.16 |
| 2026-09-22 00:00 |
20:25:50.85 |
-21:06:13.6 |
HIP 100740 |
6.27 |
| 2026-09-22 12:00 |
20:25:39.18 |
-21:07:12.4 |
HIP 100740 |
3.48 |
| 2026-09-23 00:00 |
20:25:27.61 |
-21:08:10.7 |
HIP 100740 |
1.26 |
| 2026-09-23 12:00 |
20:25:16.15 |
-21:09:08.5 |
HIP 100740 |
2.72 |
| 2026-09-24 00:00 |
20:25:04.80 |
-21:10:05.8 |
HIP 100740 |
5.39 |
| 2026-09-24 12:00 |
20:24:53.57 |
-21:11:02.6 |
HIP 100740 |
8.13 |
| 2026-09-25 00:00 |
20:24:42.44 |
-21:11:59.0 |
HIP 100608 |
8.74 |
| 2026-09-25 12:00 |
20:24:31.42 |
-21:12:54.8 |
HIP 100608 |
6.55 |
| 2026-09-26 00:00 |
20:24:20.52 |
-21:13:50.2 |
HIP 100608 |
4.95 |
| 2026-09-26 12:00 |
20:24:09.72 |
-21:14:45.1 |
HIP 100608 |
4.55 |
| 2026-09-27 00:00 |
20:23:59.04 |
-21:15:39.4 |
HIP 100608 |
5.58 |
| 2026-09-27 12:00 |
20:23:48.47 |
-21:16:33.3 |
HIP 100568 |
6.30 |
| 2026-09-28 00:00 |
20:23:38.01 |
-21:17:26.7 |
HIP 100568 |
4.67 |
| 2026-09-28 12:00 |
20:23:27.67 |
-21:18:19.7 |
HIP 100568 |
4.18 |
| 2026-09-29 00:00 |
20:23:17.44 |
-21:19:12.1 |
HIP 100568 |
5.10 |
| 2026-09-29 12:00 |
20:23:07.32 |
-21:20:04.1 |
HIP 100568 |
6.87 |
| 2026-09-30 00:00 |
20:22:57.32 |
-21:20:55.5 |
HIP 100568 |
8.97 |
| 2026-09-30 12:00 |
20:22:47.43 |
-21:21:46.5 |
HIP 100568 |
11.20 |
| 2026-10-01 00:00 |
20:22:37.65 |
-21:22:37.0 |
HIP 100568 |
13.48 |
| 2026-10-01 12:00 |
20:22:27.99 |
-21:23:27.1 |
HIP 100394 |
12.94 |
| 2026-10-02 00:00 |
20:22:18.45 |
-21:24:16.6 |
HIP 100394 |
10.64 |
| 2026-10-02 12:00 |
20:22:09.02 |
-21:25:05.7 |
HIP 100394 |
8.41 |
| 2026-10-03 00:00 |
20:21:59.70 |
-21:25:54.3 |
HIP 100394 |
6.29 |
| 2026-10-03 12:00 |
20:21:50.50 |
-21:26:42.4 |
HIP 100394 |
4.40 |
| 2026-10-04 00:00 |
20:21:41.42 |
-21:27:30.0 |
HIP 100394 |
3.10 |
| 2026-10-04 12:00 |
20:21:32.46 |
-21:28:17.2 |
HIP 100394 |
3.17 |
| 2026-10-05 00:00 |
20:21:23.61 |
-21:29:03.8 |
HIP 100394 |
4.50 |
| 2026-10-05 12:00 |
20:21:14.87 |
-21:29:50.1 |
HIP 100394 |
6.31 |
| 2026-10-06 00:00 |
20:21:06.26 |
-21:30:35.8 |
HIP 100394 |
8.27 |
| 2026-10-06 12:00 |
20:20:57.76 |
-21:31:21.0 |
HIP 100394 |
10.28 |
| 2026-10-07 00:00 |
20:20:49.38 |
-21:32:05.8 |
HIP 100394 |
12.29 |
| 2026-10-07 12:00 |
20:20:41.12 |
-21:32:50.2 |
HIP 100394 |
14.30 |
| 2026-10-08 00:00 |
20:20:32.97 |
-21:33:34.0 |
HIP 100394 |
16.30 |
| 2026-10-08 12:00 |
20:20:24.94 |
-21:34:17.4 |
HIP 100394 |
18.27 |
| 2026-10-09 00:00 |
20:20:17.03 |
-21:35:00.3 |
HIP 100394 |
20.22 |
| 2026-10-09 12:00 |
20:20:09.24 |
-21:35:42.8 |
HIP 100394 |
22.15 |
| 2026-10-10 00:00 |
20:20:01.57 |
-21:36:24.8 |
HIP 100394 |
24.05 |
| 2026-10-10 12:00 |
20:19:54.01 |
-21:37:06.3 |
HIP 100394 |
25.93 |
| 2026-10-11 00:00 |
20:19:46.58 |
-21:37:47.3 |
HIP 100062 |
26.72 |