| Parameter |
Value |
| Designation |
P/2015 R2 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2015-06-08T04:48:20.191680Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:14Z |
| Obs used |
24 |
| NEO |
- |
| M1 |
15.600 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-09-13.0000000 |
| e |
0.45202974 |
| q (au) |
2.473558 |
| a (au) |
4.514038 |
| i (deg) |
15.551673 |
| Ω (om, deg) |
168.668252 |
| ω (w, deg) |
149.648582 |
| M (ma, deg) |
9.947882 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.425 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.425 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.705 |
| k |
1.000 |
| δ90 |
10.000 |
| 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) |
| 2026-05-12 00:00 |
03:59:02.95 |
+08:18:34.9 |
HIP 18566 |
9.01 |
| 2026-05-12 12:00 |
03:59:37.25 |
+08:20:13.9 |
HIP 18566 |
16.88 |
| 2026-05-13 00:00 |
04:00:11.55 |
+08:21:52.0 |
HIP 18763 |
15.06 |
| 2026-05-13 12:00 |
04:00:45.85 |
+08:23:29.2 |
HIP 18763 |
6.82 |
| 2026-05-14 00:00 |
04:01:20.15 |
+08:25:05.7 |
HIP 18763 |
3.94 |
| 2026-05-14 12:00 |
04:01:54.45 |
+08:26:41.3 |
HIP 18763 |
11.56 |
| 2026-05-15 00:00 |
04:02:28.74 |
+08:28:16.2 |
HIP 18763 |
20.01 |
| 2026-05-15 12:00 |
04:03:03.03 |
+08:29:50.1 |
HIP 18887 |
21.47 |
| 2026-05-16 00:00 |
04:03:37.31 |
+08:31:23.3 |
HIP 18975 |
20.12 |
| 2026-05-16 12:00 |
04:04:11.58 |
+08:32:55.6 |
HIP 18975 |
21.42 |
| 2026-05-17 00:00 |
04:04:45.85 |
+08:34:27.1 |
HIP 19147 |
21.98 |
| 2026-05-17 12:00 |
04:05:20.12 |
+08:35:57.8 |
HIP 19147 |
14.31 |
| 2026-05-18 00:00 |
04:05:54.37 |
+08:37:27.6 |
HIP 19147 |
8.64 |
| 2026-05-18 12:00 |
04:06:28.62 |
+08:38:56.5 |
HIP 19147 |
9.59 |
| 2026-05-19 00:00 |
04:07:02.85 |
+08:40:24.7 |
HIP 19147 |
16.02 |
| 2026-05-19 12:00 |
04:07:37.08 |
+08:41:51.9 |
HIP 19328 |
20.37 |
| 2026-05-20 00:00 |
04:08:11.29 |
+08:43:18.4 |
HIP 19328 |
17.39 |
| 2026-05-20 12:00 |
04:08:45.49 |
+08:44:44.0 |
HIP 19328 |
18.34 |
| 2026-05-21 00:00 |
04:09:19.68 |
+08:46:08.7 |
HIP 19328 |
22.74 |
| 2026-05-21 12:00 |
04:09:53.86 |
+08:47:32.6 |
HIP 19532 |
23.14 |
| 2026-05-22 00:00 |
04:10:28.02 |
+08:48:55.6 |
HIP 19532 |
18.85 |
| 2026-05-22 12:00 |
04:11:02.17 |
+08:50:17.8 |
HIP 19532 |
17.93 |
| 2026-05-23 00:00 |
04:11:36.31 |
+08:51:39.1 |
HIP 19623 |
18.93 |
| 2026-05-23 12:00 |
04:12:10.43 |
+08:52:59.6 |
HIP 19623 |
14.75 |
| 2026-05-24 00:00 |
04:12:44.53 |
+08:54:19.2 |
HIP 19718 |
11.57 |
| 2026-05-24 12:00 |
04:13:18.61 |
+08:55:38.0 |
HIP 19718 |
3.82 |
| 2026-05-25 00:00 |
04:13:52.68 |
+08:56:55.9 |
HIP 19718 |
6.35 |
| 2026-05-25 12:00 |
04:14:26.73 |
+08:58:12.9 |
HIP 19718 |
14.52 |
| 2026-05-26 00:00 |
04:15:00.77 |
+08:59:29.1 |
HIP 19860 |
9.74 |
| 2026-05-26 12:00 |
04:15:34.78 |
+09:00:44.5 |
HIP 19860 |
7.23 |
| 2026-05-27 00:00 |
04:16:08.78 |
+09:01:59.0 |
HIP 19860 |
12.39 |
| 2026-05-27 12:00 |
04:16:42.75 |
+09:03:12.6 |
HIP 19860 |
19.96 |
| 2026-05-28 00:00 |
04:17:16.70 |
+09:04:25.3 |
HIP 20068 |
14.36 |
| 2026-05-28 12:00 |
04:17:50.64 |
+09:05:37.2 |
HIP 20068 |
6.33 |
| 2026-05-29 00:00 |
04:18:24.55 |
+09:06:48.3 |
HIP 20068 |
4.12 |
| 2026-05-29 12:00 |
04:18:58.44 |
+09:07:58.5 |
HIP 20165 |
11.16 |
| 2026-05-30 00:00 |
04:19:32.31 |
+09:09:07.8 |
HIP 20165 |
9.42 |
| 2026-05-30 12:00 |
04:20:06.15 |
+09:10:16.2 |
HIP 20281 |
11.06 |
| 2026-05-31 00:00 |
04:20:39.97 |
+09:11:23.8 |
HIP 20281 |
3.06 |
| 2026-05-31 12:00 |
04:21:13.77 |
+09:12:30.6 |
HIP 20281 |
6.18 |
| 2026-06-01 00:00 |
04:21:47.54 |
+09:13:36.4 |
HIP 20281 |
14.44 |
| 2026-06-01 12:00 |
04:22:21.29 |
+09:14:41.4 |
HIP 20458 |
9.47 |
| 2026-06-02 00:00 |
04:22:55.02 |
+09:15:45.6 |
HIP 20458 |
1.41 |