| Parameter |
Value |
| Designation |
P/2021 R1 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-12-17T19:36:46.062720Z |
| Orbit solution date (soln_date, UTC) |
2022-12-08T23:43:17Z |
| Obs used |
127 |
| NEO |
- |
| M1 |
7.500 |
| K1 |
15.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-09-04T08:31:35.241600Z |
| Discovery magnitude (MPC) |
20.60 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2022-02-25.0000000 |
| e |
0.41886575 |
| q (au) |
4.885582 |
| a (au) |
8.406977 |
| i (deg) |
5.521079 |
| Ω (om, deg) |
143.406228 |
| ω (w, deg) |
220.343748 |
| M (ma, deg) |
2.797322 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.514 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.514 |
| n |
6.000 |
| gf |
0.923 |
| gb |
-0.916 |
| k |
1.000 |
| δ90 |
1.000 |
| 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) |
| 2026-03-26 00:00 |
07:21:41.57 |
+19:27:56.6 |
HIP 35693 |
16.75 |
| 2026-03-26 12:00 |
07:21:42.93 |
+19:28:09.9 |
HIP 35693 |
16.92 |
| 2026-03-27 00:00 |
07:21:44.42 |
+19:28:22.9 |
HIP 35693 |
17.09 |
| 2026-03-27 12:00 |
07:21:46.04 |
+19:28:35.7 |
HIP 35693 |
17.27 |
| 2026-03-28 00:00 |
07:21:47.79 |
+19:28:48.1 |
HIP 35693 |
17.44 |
| 2026-03-28 12:00 |
07:21:49.66 |
+19:29:00.3 |
HIP 35693 |
17.62 |
| 2026-03-29 00:00 |
07:21:51.67 |
+19:29:12.2 |
HIP 35693 |
17.81 |
| 2026-03-29 12:00 |
07:21:53.80 |
+19:29:23.9 |
HIP 35693 |
18.01 |
| 2026-03-30 00:00 |
07:21:56.06 |
+19:29:35.2 |
HIP 35693 |
18.21 |
| 2026-03-30 12:00 |
07:21:58.45 |
+19:29:46.3 |
HIP 35693 |
18.43 |
| 2026-03-31 00:00 |
07:22:00.96 |
+19:29:57.1 |
HIP 35693 |
18.67 |
| 2026-03-31 12:00 |
07:22:03.60 |
+19:30:07.7 |
HIP 35693 |
18.92 |
| 2026-04-01 00:00 |
07:22:06.36 |
+19:30:17.9 |
HIP 35693 |
19.19 |
| 2026-04-01 12:00 |
07:22:09.25 |
+19:30:27.9 |
HIP 35693 |
19.48 |
| 2026-04-02 00:00 |
07:22:12.27 |
+19:30:37.6 |
HIP 35693 |
19.79 |
| 2026-04-02 12:00 |
07:22:15.41 |
+19:30:47.1 |
HIP 35693 |
20.13 |
| 2026-04-03 00:00 |
07:22:18.67 |
+19:30:56.2 |
HIP 35693 |
20.50 |
| 2026-04-03 12:00 |
07:22:22.06 |
+19:31:05.1 |
HIP 35693 |
20.89 |
| 2026-04-04 00:00 |
07:22:25.57 |
+19:31:13.7 |
HIP 35693 |
21.32 |
| 2026-04-04 12:00 |
07:22:29.21 |
+19:31:22.0 |
HIP 35693 |
21.77 |
| 2026-04-05 00:00 |
07:22:32.96 |
+19:31:30.0 |
HIP 35693 |
22.26 |
| 2026-04-05 12:00 |
07:22:36.84 |
+19:31:37.8 |
HIP 35693 |
22.78 |
| 2026-04-06 00:00 |
07:22:40.85 |
+19:31:45.3 |
HIP 35693 |
23.34 |
| 2026-04-06 12:00 |
07:22:44.97 |
+19:31:52.5 |
HIP 35693 |
23.94 |
| 2026-04-07 00:00 |
07:22:49.22 |
+19:31:59.4 |
HIP 35693 |
24.56 |
| 2026-04-07 12:00 |
07:22:53.59 |
+19:32:06.0 |
HIP 35693 |
25.23 |
| 2026-04-08 00:00 |
07:22:58.08 |
+19:32:12.4 |
HIP 35693 |
25.94 |
| 2026-04-08 12:00 |
07:23:02.69 |
+19:32:18.4 |
HIP 35693 |
26.68 |
| 2026-04-09 00:00 |
07:23:07.41 |
+19:32:24.2 |
HIP 35693 |
27.46 |
| 2026-04-09 12:00 |
07:23:12.26 |
+19:32:29.7 |
HIP 35693 |
28.28 |
| 2026-04-10 00:00 |
07:23:17.23 |
+19:32:35.0 |
HIP 35693 |
29.13 |
| 2026-04-10 12:00 |
07:23:22.32 |
+19:32:39.9 |
HIP 35693 |
30.03 |
| 2026-04-11 00:00 |
07:23:27.52 |
+19:32:44.6 |
HIP 35693 |
30.96 |
| 2026-04-11 12:00 |
07:23:32.85 |
+19:32:49.0 |
HIP 35693 |
31.93 |
| 2026-04-12 00:00 |
07:23:38.29 |
+19:32:53.0 |
HIP 35969 |
31.94 |
| 2026-04-12 12:00 |
07:23:43.85 |
+19:32:56.9 |
HIP 35969 |
31.22 |
| 2026-04-13 00:00 |
07:23:49.52 |
+19:33:00.4 |
HIP 35969 |
30.53 |
| 2026-04-13 12:00 |
07:23:55.32 |
+19:33:03.6 |
HIP 35969 |
29.87 |
| 2026-04-14 00:00 |
07:24:01.22 |
+19:33:06.6 |
HIP 35969 |
29.26 |
| 2026-04-14 12:00 |
07:24:07.25 |
+19:33:09.2 |
HIP 35969 |
28.69 |
| 2026-04-15 00:00 |
07:24:13.39 |
+19:33:11.6 |
HIP 35969 |
28.18 |
| 2026-04-15 12:00 |
07:24:19.64 |
+19:33:13.7 |
HIP 35969 |
27.74 |
| 2026-04-16 00:00 |
07:24:26.01 |
+19:33:15.5 |
HIP 35969 |
27.37 |