| 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) |
| 2026-06-01 00:00 |
08:22:23.56 |
+10:29:24.4 |
HIP 41027 |
10.30 |
| 2026-06-01 12:00 |
08:22:34.24 |
+10:29:08.8 |
HIP 41027 |
10.88 |
| 2026-06-02 00:00 |
08:22:44.99 |
+10:28:52.8 |
HIP 41027 |
12.05 |
| 2026-06-02 12:00 |
08:22:55.82 |
+10:28:36.2 |
HIP 41027 |
13.65 |
| 2026-06-03 00:00 |
08:23:06.73 |
+10:28:19.2 |
HIP 41163 |
15.30 |
| 2026-06-03 12:00 |
08:23:17.72 |
+10:28:01.6 |
HIP 41163 |
13.52 |
| 2026-06-04 00:00 |
08:23:28.79 |
+10:27:43.6 |
HIP 41163 |
12.09 |
| 2026-06-04 12:00 |
08:23:39.93 |
+10:27:25.0 |
HIP 41163 |
11.16 |
| 2026-06-05 00:00 |
08:23:51.14 |
+10:27:06.0 |
HIP 41163 |
10.87 |
| 2026-06-05 12:00 |
08:24:02.43 |
+10:26:46.4 |
HIP 41163 |
11.29 |
| 2026-06-06 00:00 |
08:24:13.80 |
+10:26:26.4 |
HIP 41163 |
12.36 |
| 2026-06-06 12:00 |
08:24:25.24 |
+10:26:05.8 |
HIP 41163 |
13.94 |
| 2026-06-07 00:00 |
08:24:36.75 |
+10:25:44.8 |
HIP 41163 |
15.89 |
| 2026-06-07 12:00 |
08:24:48.33 |
+10:25:23.2 |
HIP 41163 |
18.10 |
| 2026-06-08 00:00 |
08:24:59.98 |
+10:25:01.2 |
HIP 41163 |
20.50 |
| 2026-06-08 12:00 |
08:25:11.71 |
+10:24:38.7 |
HIP 41163 |
23.02 |
| 2026-06-09 00:00 |
08:25:23.50 |
+10:24:15.7 |
HIP 41378 |
25.07 |
| 2026-06-09 12:00 |
08:25:35.37 |
+10:23:52.1 |
HIP 41378 |
23.01 |
| 2026-06-10 00:00 |
08:25:47.30 |
+10:23:28.1 |
HIP 41378 |
21.15 |
| 2026-06-10 12:00 |
08:25:59.31 |
+10:23:03.6 |
HIP 41378 |
19.55 |
| 2026-06-11 00:00 |
08:26:11.38 |
+10:22:38.6 |
HIP 41378 |
18.28 |
| 2026-06-11 12:00 |
08:26:23.52 |
+10:22:13.1 |
HIP 41378 |
17.43 |
| 2026-06-12 00:00 |
08:26:35.72 |
+10:21:47.2 |
HIP 41378 |
17.07 |
| 2026-06-12 12:00 |
08:26:47.99 |
+10:21:20.7 |
HIP 41378 |
17.25 |
| 2026-06-13 00:00 |
08:27:00.33 |
+10:20:53.7 |
HIP 41378 |
17.95 |
| 2026-06-13 12:00 |
08:27:12.73 |
+10:20:26.3 |
HIP 41378 |
19.12 |
| 2026-06-14 00:00 |
08:27:25.19 |
+10:19:58.3 |
HIP 41378 |
20.70 |
| 2026-06-14 12:00 |
08:27:37.72 |
+10:19:29.9 |
HIP 41613 |
20.75 |
| 2026-06-15 00:00 |
08:27:50.31 |
+10:19:01.0 |
HIP 41613 |
17.62 |
| 2026-06-15 12:00 |
08:28:02.96 |
+10:18:31.6 |
HIP 41613 |
14.48 |
| 2026-06-16 00:00 |
08:28:15.67 |
+10:18:01.7 |
HIP 41613 |
11.31 |
| 2026-06-16 12:00 |
08:28:28.44 |
+10:17:31.4 |
HIP 41613 |
8.14 |
| 2026-06-17 00:00 |
08:28:41.27 |
+10:17:00.5 |
HIP 41613 |
4.97 |
| 2026-06-17 12:00 |
08:28:54.17 |
+10:16:29.2 |
HIP 41613 |
1.87 |
| 2026-06-18 00:00 |
08:29:07.11 |
+10:15:57.4 |
HIP 41613 |
1.73 |
| 2026-06-18 12:00 |
08:29:20.12 |
+10:15:25.1 |
HIP 41613 |
4.85 |
| 2026-06-19 00:00 |
08:29:33.18 |
+10:14:52.4 |
HIP 41613 |
8.08 |
| 2026-06-19 12:00 |
08:29:46.30 |
+10:14:19.2 |
HIP 41613 |
11.35 |
| 2026-06-20 00:00 |
08:29:59.47 |
+10:13:45.5 |
HIP 41613 |
14.63 |
| 2026-06-20 12:00 |
08:30:12.70 |
+10:13:11.3 |
HIP 41613 |
17.93 |
| 2026-06-21 00:00 |
08:30:25.97 |
+10:12:36.7 |
HIP 41613 |
21.24 |
| 2026-06-21 12:00 |
08:30:39.31 |
+10:12:01.6 |
HIP 41613 |
24.57 |
| 2026-06-22 00:00 |
08:30:52.69 |
+10:11:26.1 |
HIP 41843 |
27.23 |