| Parameter |
Value |
| Designation |
C/2015 J2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-09-08T21:55:57.529920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:10Z |
| Obs used |
99 |
| NEO |
- |
| M1 |
7.200 |
| K1 |
14.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-07-15.0000000 |
| e |
0.98250509 |
| q (au) |
4.320386 |
| a (au) |
246.951051 |
| i (deg) |
17.281830 |
| Ω (om, deg) |
56.755871 |
| ω (w, deg) |
203.688946 |
| M (ma, deg) |
359.985799 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.150 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.150 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.722 |
| k |
0.800 |
| δ90 |
9.998 |
| 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 |
02:03:13.03 |
+04:44:05.3 |
HIP 9611 |
8.86 |
| 2026-03-26 12:00 |
02:03:17.64 |
+04:44:37.5 |
HIP 9611 |
7.80 |
| 2026-03-27 00:00 |
02:03:22.26 |
+04:45:09.7 |
HIP 9611 |
6.81 |
| 2026-03-27 12:00 |
02:03:26.90 |
+04:45:41.9 |
HIP 9611 |
5.92 |
| 2026-03-28 00:00 |
02:03:31.56 |
+04:46:14.1 |
HIP 9611 |
5.19 |
| 2026-03-28 12:00 |
02:03:36.23 |
+04:46:46.3 |
HIP 9611 |
4.71 |
| 2026-03-29 00:00 |
02:03:40.91 |
+04:47:18.5 |
HIP 9611 |
4.55 |
| 2026-03-29 12:00 |
02:03:45.61 |
+04:47:50.7 |
HIP 9611 |
4.74 |
| 2026-03-30 00:00 |
02:03:50.32 |
+04:48:22.9 |
HIP 9611 |
5.26 |
| 2026-03-30 12:00 |
02:03:55.05 |
+04:48:55.0 |
HIP 9611 |
6.02 |
| 2026-03-31 00:00 |
02:03:59.79 |
+04:49:27.2 |
HIP 9611 |
6.94 |
| 2026-03-31 12:00 |
02:04:04.55 |
+04:49:59.4 |
HIP 9611 |
7.97 |
| 2026-04-01 00:00 |
02:04:09.32 |
+04:50:31.5 |
HIP 9611 |
9.07 |
| 2026-04-01 12:00 |
02:04:14.10 |
+04:51:03.6 |
HIP 9611 |
10.23 |
| 2026-04-02 00:00 |
02:04:18.89 |
+04:51:35.8 |
HIP 9611 |
11.42 |
| 2026-04-02 12:00 |
02:04:23.70 |
+04:52:07.9 |
HIP 9611 |
12.63 |
| 2026-04-03 00:00 |
02:04:28.52 |
+04:52:39.9 |
HIP 9611 |
13.87 |
| 2026-04-03 12:00 |
02:04:33.35 |
+04:53:12.0 |
HIP 9611 |
15.12 |
| 2026-04-04 00:00 |
02:04:38.20 |
+04:53:44.0 |
HIP 9611 |
16.39 |
| 2026-04-04 12:00 |
02:04:43.05 |
+04:54:16.1 |
HIP 9611 |
17.67 |
| 2026-04-05 00:00 |
02:04:47.92 |
+04:54:48.1 |
HIP 9611 |
18.95 |
| 2026-04-05 12:00 |
02:04:52.79 |
+04:55:20.0 |
HIP 9611 |
20.24 |
| 2026-04-06 00:00 |
02:04:57.68 |
+04:55:52.0 |
HIP 9611 |
21.54 |
| 2026-04-06 12:00 |
02:05:02.58 |
+04:56:23.9 |
HIP 9611 |
22.85 |
| 2026-04-07 00:00 |
02:05:07.49 |
+04:56:55.7 |
HIP 9611 |
24.16 |
| 2026-04-07 12:00 |
02:05:12.40 |
+04:57:27.6 |
HIP 9791 |
23.42 |
| 2026-04-08 00:00 |
02:05:17.33 |
+04:57:59.4 |
HIP 9791 |
22.41 |
| 2026-04-08 12:00 |
02:05:22.27 |
+04:58:31.2 |
HIP 9791 |
21.43 |
| 2026-04-09 00:00 |
02:05:27.21 |
+04:59:02.9 |
HIP 9791 |
20.49 |
| 2026-04-09 12:00 |
02:05:32.17 |
+04:59:34.6 |
HIP 9791 |
19.61 |
| 2026-04-10 00:00 |
02:05:37.13 |
+05:00:06.2 |
HIP 9791 |
18.77 |
| 2026-04-10 12:00 |
02:05:42.10 |
+05:00:37.9 |
HIP 9791 |
18.00 |
| 2026-04-11 00:00 |
02:05:47.08 |
+05:01:09.4 |
HIP 9791 |
17.29 |
| 2026-04-11 12:00 |
02:05:52.07 |
+05:01:40.9 |
HIP 9791 |
16.67 |
| 2026-04-12 00:00 |
02:05:57.06 |
+05:02:12.4 |
HIP 9791 |
16.14 |
| 2026-04-12 12:00 |
02:06:02.06 |
+05:02:43.8 |
HIP 9791 |
15.70 |
| 2026-04-13 00:00 |
02:06:07.07 |
+05:03:15.2 |
HIP 9791 |
15.38 |
| 2026-04-13 12:00 |
02:06:12.08 |
+05:03:46.5 |
HIP 9791 |
15.17 |
| 2026-04-14 00:00 |
02:06:17.10 |
+05:04:17.8 |
HIP 9791 |
15.07 |
| 2026-04-14 12:00 |
02:06:22.13 |
+05:04:49.0 |
HIP 9791 |
15.11 |
| 2026-04-15 00:00 |
02:06:27.16 |
+05:05:20.2 |
HIP 9791 |
15.26 |
| 2026-04-15 12:00 |
02:06:32.20 |
+05:05:51.2 |
HIP 9791 |
15.53 |
| 2026-04-16 00:00 |
02:06:37.24 |
+05:06:22.3 |
HIP 9791 |
15.92 |