P/2021 HS (PANSTARRS)
| Parameter |
Value |
| Designation |
P/2021 HS (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-08-06T09:22:36.661440Z |
| Orbit solution date (soln_date, UTC) |
2021-12-17T03:12:57Z |
| Obs used |
181 |
| NEO |
Yes |
| M1 |
20.600 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-07-03.0000000 |
| e |
0.81016790 |
| q (au) |
0.796446 |
| a (au) |
4.195528 |
| i (deg) |
12.171396 |
| Ω (om, deg) |
262.395858 |
| ω (w, deg) |
46.086196 |
| M (ma, deg) |
356.055743 |
Magnitude
Scatter + Global Linear
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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 |
08:33:42.52 |
+08:08:53.6 |
HIP 42049 |
19.78 |
| 2026-02-03 12:00 |
08:33:27.54 |
+08:09:49.0 |
HIP 42049 |
20.70 |
| 2026-02-04 00:00 |
08:33:12.58 |
+08:10:44.7 |
HIP 42049 |
22.24 |
| 2026-02-04 12:00 |
08:32:57.65 |
+08:11:40.8 |
HIP 41840 |
19.70 |
| 2026-02-05 00:00 |
08:32:42.75 |
+08:12:37.1 |
HIP 41840 |
16.02 |
| 2026-02-05 12:00 |
08:32:27.87 |
+08:13:33.7 |
HIP 41840 |
12.42 |
| 2026-02-06 00:00 |
08:32:13.03 |
+08:14:30.5 |
HIP 41840 |
8.98 |
| 2026-02-06 12:00 |
08:31:58.22 |
+08:15:27.7 |
HIP 41840 |
5.98 |
| 2026-02-07 00:00 |
08:31:43.44 |
+08:16:25.1 |
HIP 41840 |
4.43 |
| 2026-02-07 12:00 |
08:31:28.70 |
+08:17:22.7 |
HIP 41840 |
5.65 |
| 2026-02-08 00:00 |
08:31:14.00 |
+08:18:20.6 |
HIP 41840 |
8.51 |
| 2026-02-08 12:00 |
08:30:59.33 |
+08:19:18.8 |
HIP 41840 |
11.87 |
| 2026-02-09 00:00 |
08:30:44.71 |
+08:20:17.1 |
HIP 41840 |
15.41 |
| 2026-02-09 12:00 |
08:30:30.13 |
+08:21:15.7 |
HIP 41652 |
13.82 |
| 2026-02-10 00:00 |
08:30:15.60 |
+08:22:14.5 |
HIP 41652 |
10.09 |
| 2026-02-10 12:00 |
08:30:01.11 |
+08:23:13.5 |
HIP 41652 |
6.38 |
| 2026-02-11 00:00 |
08:29:46.68 |
+08:24:12.8 |
HIP 41652 |
2.67 |
| 2026-02-11 12:00 |
08:29:32.29 |
+08:25:12.2 |
HIP 41652 |
1.03 |
| 2026-02-12 00:00 |
08:29:17.95 |
+08:26:11.8 |
HIP 41652 |
4.71 |
| 2026-02-12 12:00 |
08:29:03.67 |
+08:27:11.5 |
HIP 41652 |
8.37 |
| 2026-02-13 00:00 |
08:28:49.45 |
+08:28:11.5 |
HIP 41652 |
12.03 |
| 2026-02-13 12:00 |
08:28:35.28 |
+08:29:11.6 |
HIP 41652 |
15.67 |
| 2026-02-14 00:00 |
08:28:21.18 |
+08:30:11.8 |
HIP 41652 |
19.30 |
| 2026-02-14 12:00 |
08:28:07.13 |
+08:31:12.2 |
HIP 41652 |
22.92 |
| 2026-02-15 00:00 |
08:27:53.15 |
+08:32:12.7 |
HIP 41652 |
26.52 |
| 2026-02-15 12:00 |
08:27:39.23 |
+08:33:13.4 |
HIP 41652 |
30.11 |
| 2026-02-16 00:00 |
08:27:25.38 |
+08:34:14.2 |
HIP 41652 |
33.68 |
| 2026-02-16 12:00 |
08:27:11.59 |
+08:35:15.1 |
HIP 41652 |
37.23 |
| 2026-02-17 00:00 |
08:26:57.88 |
+08:36:16.1 |
HIP 41340 |
37.98 |
| 2026-02-17 12:00 |
08:26:44.24 |
+08:37:17.2 |
HIP 41204 |
36.91 |
| 2026-02-18 00:00 |
08:26:30.67 |
+08:38:18.4 |
HIP 41204 |
34.45 |
| 2026-02-18 12:00 |
08:26:17.18 |
+08:39:19.6 |
HIP 41204 |
32.19 |
| 2026-02-19 00:00 |
08:26:03.76 |
+08:40:20.9 |
HIP 41204 |
30.19 |
| 2026-02-19 12:00 |
08:25:50.42 |
+08:41:22.3 |
HIP 41204 |
28.49 |
| 2026-02-20 00:00 |
08:25:37.16 |
+08:42:23.8 |
HIP 41204 |
27.14 |
| 2026-02-20 12:00 |
08:25:23.98 |
+08:43:25.3 |
HIP 41204 |
26.18 |
| 2026-02-21 00:00 |
08:25:10.89 |
+08:44:26.8 |
HIP 41204 |
25.65 |
| 2026-02-21 12:00 |
08:24:57.88 |
+08:45:28.4 |
HIP 41204 |
25.57 |
| 2026-02-22 00:00 |
08:24:44.96 |
+08:46:30.0 |
HIP 41150 |
25.15 |
| 2026-02-22 12:00 |
08:24:32.12 |
+08:47:31.6 |
HIP 41150 |
24.41 |
| 2026-02-23 00:00 |
08:24:19.37 |
+08:48:33.2 |
HIP 41150 |
24.13 |
| 2026-02-23 12:00 |
08:24:06.71 |
+08:49:34.8 |
HIP 41150 |
24.30 |
| 2026-02-24 00:00 |
08:23:54.15 |
+08:50:36.4 |
HIP 41183 |
23.90 |