| 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) |
| 2026-03-26 00:00 |
03:06:33.34 |
+04:49:08.7 |
HIP 14421 |
5.55 |
| 2026-03-26 12:00 |
03:07:05.17 |
+04:51:51.6 |
HIP 14496 |
9.63 |
| 2026-03-27 00:00 |
03:07:37.06 |
+04:54:34.0 |
HIP 14496 |
8.64 |
| 2026-03-27 12:00 |
03:08:09.00 |
+04:57:15.9 |
HIP 14496 |
14.07 |
| 2026-03-28 00:00 |
03:08:41.00 |
+04:59:57.2 |
HIP 14676 |
18.41 |
| 2026-03-28 12:00 |
03:09:13.05 |
+05:02:38.1 |
HIP 14676 |
11.16 |
| 2026-03-29 00:00 |
03:09:45.15 |
+05:05:18.4 |
HIP 14676 |
7.21 |
| 2026-03-29 12:00 |
03:10:17.30 |
+05:07:58.2 |
HIP 14676 |
11.04 |
| 2026-03-30 00:00 |
03:10:49.51 |
+05:10:37.4 |
HIP 14676 |
18.29 |
| 2026-03-30 12:00 |
03:11:21.76 |
+05:13:16.1 |
HIP 14829 |
22.16 |
| 2026-03-31 00:00 |
03:11:54.07 |
+05:15:54.3 |
HIP 14829 |
20.37 |
| 2026-03-31 12:00 |
03:12:26.43 |
+05:18:31.9 |
HIP 14829 |
21.97 |
| 2026-04-01 00:00 |
03:12:58.83 |
+05:21:09.0 |
HIP 14829 |
26.35 |
| 2026-04-01 12:00 |
03:13:31.28 |
+05:23:45.5 |
HIP 14829 |
32.42 |
| 2026-04-02 00:00 |
03:14:03.78 |
+05:26:21.4 |
HIP 15157 |
30.94 |
| 2026-04-02 12:00 |
03:14:36.32 |
+05:28:56.8 |
HIP 15157 |
24.30 |
| 2026-04-03 00:00 |
03:15:08.92 |
+05:31:31.6 |
HIP 15157 |
19.19 |
| 2026-04-03 12:00 |
03:15:41.55 |
+05:34:05.9 |
HIP 15157 |
17.06 |
| 2026-04-04 00:00 |
03:16:14.24 |
+05:36:39.6 |
HIP 15157 |
18.97 |
| 2026-04-04 12:00 |
03:16:46.96 |
+05:39:12.7 |
HIP 15299 |
10.65 |
| 2026-04-05 00:00 |
03:17:19.73 |
+05:41:45.2 |
HIP 15299 |
3.49 |
| 2026-04-05 12:00 |
03:17:52.55 |
+05:44:17.1 |
HIP 15299 |
7.55 |
| 2026-04-06 00:00 |
03:18:25.40 |
+05:46:48.5 |
HIP 15397 |
2.39 |
| 2026-04-06 12:00 |
03:18:58.30 |
+05:49:19.3 |
HIP 15397 |
6.92 |
| 2026-04-07 00:00 |
03:19:31.24 |
+05:51:49.4 |
HIP 15397 |
15.39 |
| 2026-04-07 12:00 |
03:20:04.22 |
+05:54:19.0 |
HIP 15542 |
19.18 |
| 2026-04-08 00:00 |
03:20:37.25 |
+05:56:47.9 |
HIP 15542 |
17.37 |
| 2026-04-08 12:00 |
03:21:10.31 |
+05:59:16.3 |
HIP 15542 |
19.57 |
| 2026-04-09 00:00 |
03:21:43.41 |
+06:01:44.0 |
HIP 15670 |
19.93 |
| 2026-04-09 12:00 |
03:22:16.55 |
+06:04:11.2 |
HIP 15670 |
22.96 |
| 2026-04-10 00:00 |
03:22:49.73 |
+06:06:37.7 |
HIP 15670 |
28.37 |
| 2026-04-10 12:00 |
03:23:22.94 |
+06:09:03.5 |
HIP 15670 |
35.08 |
| 2026-04-11 00:00 |
03:23:56.20 |
+06:11:28.8 |
HIP 15978 |
30.93 |
| 2026-04-11 12:00 |
03:24:29.49 |
+06:13:53.4 |
HIP 15978 |
25.70 |
| 2026-04-12 00:00 |
03:25:02.81 |
+06:16:17.4 |
HIP 15978 |
22.64 |
| 2026-04-12 12:00 |
03:25:36.17 |
+06:18:40.7 |
HIP 15978 |
22.64 |
| 2026-04-13 00:00 |
03:26:09.57 |
+06:21:03.4 |
HIP 16050 |
20.32 |
| 2026-04-13 12:00 |
03:26:43.00 |
+06:23:25.5 |
HIP 16050 |
16.16 |
| 2026-04-14 00:00 |
03:27:16.46 |
+06:25:46.9 |
HIP 16050 |
16.10 |
| 2026-04-14 12:00 |
03:27:49.96 |
+06:28:07.6 |
HIP 16050 |
20.17 |
| 2026-04-15 00:00 |
03:28:23.48 |
+06:30:27.7 |
HIP 16050 |
26.55 |
| 2026-04-15 12:00 |
03:28:57.04 |
+06:32:47.1 |
HIP 16050 |
33.95 |
| 2026-04-16 00:00 |
03:29:30.63 |
+06:35:05.9 |
HIP 16358 |
30.17 |