| 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 |
-0.548 |
| 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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
04:23:28.71 |
+09:16:48.8 |
HIP 20458 |
7.41 |
| 2026-06-03 00:00 |
04:24:02.38 |
+09:17:51.2 |
HIP 20522 |
10.14 |
| 2026-06-03 12:00 |
04:24:36.03 |
+09:18:52.8 |
HIP 20522 |
14.00 |
| 2026-06-04 00:00 |
04:25:09.65 |
+09:19:53.4 |
HIP 20522 |
20.70 |
| 2026-06-04 12:00 |
04:25:43.24 |
+09:20:53.2 |
HIP 20734 |
13.67 |
| 2026-06-05 00:00 |
04:26:16.80 |
+09:21:52.2 |
HIP 20734 |
5.41 |
| 2026-06-05 12:00 |
04:26:50.33 |
+09:22:50.2 |
HIP 20734 |
3.27 |
| 2026-06-06 00:00 |
04:27:23.83 |
+09:23:47.4 |
HIP 20734 |
11.43 |
| 2026-06-06 12:00 |
04:27:57.30 |
+09:24:43.7 |
HIP 20734 |
19.71 |
| 2026-06-07 00:00 |
04:28:30.74 |
+09:25:39.1 |
HIP 20941 |
14.58 |
| 2026-06-07 12:00 |
04:29:04.16 |
+09:26:33.7 |
HIP 20941 |
7.38 |
| 2026-06-08 00:00 |
04:29:37.53 |
+09:27:27.4 |
HIP 20941 |
5.81 |
| 2026-06-08 12:00 |
04:30:10.88 |
+09:28:20.2 |
HIP 20941 |
12.26 |
| 2026-06-09 00:00 |
04:30:44.19 |
+09:29:12.1 |
HIP 20941 |
20.08 |
| 2026-06-09 12:00 |
04:31:17.47 |
+09:30:03.2 |
HIP 20941 |
28.14 |
| 2026-06-10 00:00 |
04:31:50.72 |
+09:30:53.3 |
HIP 21269 |
29.59 |
| 2026-06-10 12:00 |
04:32:23.93 |
+09:31:42.6 |
HIP 21269 |
21.89 |
| 2026-06-11 00:00 |
04:32:57.11 |
+09:32:31.0 |
HIP 21269 |
14.76 |
| 2026-06-11 12:00 |
04:33:30.25 |
+09:33:18.5 |
HIP 21269 |
9.57 |
| 2026-06-12 00:00 |
04:34:03.35 |
+09:34:05.1 |
HIP 21269 |
10.00 |
| 2026-06-12 12:00 |
04:34:36.42 |
+09:34:50.9 |
HIP 21269 |
15.56 |
| 2026-06-13 00:00 |
04:35:09.44 |
+09:35:35.8 |
HIP 21269 |
22.75 |
| 2026-06-13 12:00 |
04:35:42.43 |
+09:36:19.7 |
HIP 21504 |
24.33 |
| 2026-06-14 00:00 |
04:36:15.38 |
+09:37:02.8 |
HIP 21504 |
18.35 |
| 2026-06-14 12:00 |
04:36:48.29 |
+09:37:45.0 |
HIP 21504 |
14.63 |
| 2026-06-15 00:00 |
04:37:21.15 |
+09:38:26.3 |
HIP 21504 |
14.96 |
| 2026-06-15 12:00 |
04:37:53.98 |
+09:39:06.7 |
HIP 21504 |
19.11 |
| 2026-06-16 00:00 |
04:38:26.76 |
+09:39:46.2 |
HIP 21710 |
22.54 |
| 2026-06-16 12:00 |
04:38:59.50 |
+09:40:24.8 |
HIP 21710 |
16.00 |
| 2026-06-17 00:00 |
04:39:32.19 |
+09:41:02.6 |
HIP 21710 |
11.62 |
| 2026-06-17 12:00 |
04:40:04.84 |
+09:41:39.4 |
HIP 21710 |
12.04 |
| 2026-06-18 00:00 |
04:40:37.44 |
+09:42:15.4 |
HIP 21761 |
12.41 |
| 2026-06-18 12:00 |
04:41:09.99 |
+09:42:50.5 |
HIP 21882 |
16.72 |
| 2026-06-19 00:00 |
04:41:42.50 |
+09:43:24.6 |
HIP 21882 |
9.64 |
| 2026-06-19 12:00 |
04:42:14.96 |
+09:43:57.9 |
HIP 21882 |
5.93 |
| 2026-06-20 00:00 |
04:42:47.37 |
+09:44:30.3 |
HIP 21954 |
8.67 |
| 2026-06-20 12:00 |
04:43:19.73 |
+09:45:01.8 |
HIP 21954 |
8.46 |
| 2026-06-21 00:00 |
04:43:52.05 |
+09:45:32.5 |
HIP 21954 |
13.97 |
| 2026-06-21 12:00 |
04:44:24.31 |
+09:46:02.2 |
HIP 22085 |
19.42 |
| 2026-06-22 00:00 |
04:44:56.52 |
+09:46:31.1 |
HIP 22085 |
17.34 |