| 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) |
| 2026-05-12 00:00 |
02:10:58.65 |
+05:31:12.5 |
HIP 10153 |
19.57 |
| 2026-05-12 12:00 |
02:11:03.53 |
+05:31:38.1 |
HIP 10153 |
19.56 |
| 2026-05-13 00:00 |
02:11:08.40 |
+05:32:03.6 |
HIP 10153 |
19.63 |
| 2026-05-13 12:00 |
02:11:13.26 |
+05:32:29.0 |
HIP 10153 |
19.78 |
| 2026-05-14 00:00 |
02:11:18.11 |
+05:32:54.2 |
HIP 10153 |
20.01 |
| 2026-05-14 12:00 |
02:11:22.95 |
+05:33:19.3 |
HIP 10153 |
20.32 |
| 2026-05-15 00:00 |
02:11:27.77 |
+05:33:44.3 |
HIP 10153 |
20.71 |
| 2026-05-15 12:00 |
02:11:32.58 |
+05:34:09.1 |
HIP 10153 |
21.17 |
| 2026-05-16 00:00 |
02:11:37.38 |
+05:34:33.7 |
HIP 10153 |
21.68 |
| 2026-05-16 12:00 |
02:11:42.17 |
+05:34:58.2 |
HIP 10153 |
22.26 |
| 2026-05-17 00:00 |
02:11:46.95 |
+05:35:22.6 |
HIP 10153 |
22.89 |
| 2026-05-17 12:00 |
02:11:51.71 |
+05:35:46.8 |
HIP 10333 |
23.55 |
| 2026-05-18 00:00 |
02:11:56.46 |
+05:36:10.8 |
HIP 10333 |
22.83 |
| 2026-05-18 12:00 |
02:12:01.19 |
+05:36:34.7 |
HIP 10333 |
22.16 |
| 2026-05-19 00:00 |
02:12:05.91 |
+05:36:58.5 |
HIP 10333 |
21.54 |
| 2026-05-19 12:00 |
02:12:10.62 |
+05:37:22.1 |
HIP 10333 |
20.97 |
| 2026-05-20 00:00 |
02:12:15.31 |
+05:37:45.5 |
HIP 10333 |
20.47 |
| 2026-05-20 12:00 |
02:12:19.99 |
+05:38:08.8 |
HIP 10333 |
20.02 |
| 2026-05-21 00:00 |
02:12:24.65 |
+05:38:31.9 |
HIP 10333 |
19.65 |
| 2026-05-21 12:00 |
02:12:29.29 |
+05:38:54.9 |
HIP 10333 |
19.34 |
| 2026-05-22 00:00 |
02:12:33.92 |
+05:39:17.7 |
HIP 10333 |
19.11 |
| 2026-05-22 12:00 |
02:12:38.54 |
+05:39:40.4 |
HIP 10333 |
18.95 |
| 2026-05-23 00:00 |
02:12:43.14 |
+05:40:02.9 |
HIP 10333 |
18.86 |
| 2026-05-23 12:00 |
02:12:47.72 |
+05:40:25.2 |
HIP 10333 |
18.85 |
| 2026-05-24 00:00 |
02:12:52.28 |
+05:40:47.3 |
HIP 10333 |
18.92 |
| 2026-05-24 12:00 |
02:12:56.83 |
+05:41:09.3 |
HIP 10333 |
19.06 |
| 2026-05-25 00:00 |
02:13:01.36 |
+05:41:31.2 |
HIP 10333 |
19.27 |
| 2026-05-25 12:00 |
02:13:05.88 |
+05:41:52.8 |
HIP 10333 |
19.54 |
| 2026-05-26 00:00 |
02:13:10.37 |
+05:42:14.3 |
HIP 10333 |
19.88 |
| 2026-05-26 12:00 |
02:13:14.85 |
+05:42:35.7 |
HIP 10333 |
20.28 |
| 2026-05-27 00:00 |
02:13:19.31 |
+05:42:56.8 |
HIP 10333 |
20.73 |
| 2026-05-27 12:00 |
02:13:23.75 |
+05:43:17.8 |
HIP 10333 |
21.24 |
| 2026-05-28 00:00 |
02:13:28.17 |
+05:43:38.7 |
HIP 10419 |
20.63 |
| 2026-05-28 12:00 |
02:13:32.58 |
+05:43:59.3 |
HIP 10419 |
19.74 |
| 2026-05-29 00:00 |
02:13:36.96 |
+05:44:19.8 |
HIP 10419 |
18.87 |
| 2026-05-29 12:00 |
02:13:41.33 |
+05:44:40.1 |
HIP 10419 |
18.05 |
| 2026-05-30 00:00 |
02:13:45.67 |
+05:45:00.2 |
HIP 10419 |
17.26 |
| 2026-05-30 12:00 |
02:13:50.00 |
+05:45:20.2 |
HIP 10419 |
16.52 |
| 2026-05-31 00:00 |
02:13:54.31 |
+05:45:40.0 |
HIP 10419 |
15.82 |
| 2026-05-31 12:00 |
02:13:58.59 |
+05:45:59.6 |
HIP 10419 |
15.19 |
| 2026-06-01 00:00 |
02:14:02.86 |
+05:46:19.0 |
HIP 10419 |
14.61 |
| 2026-06-01 12:00 |
02:14:07.10 |
+05:46:38.3 |
HIP 10419 |
14.10 |
| 2026-06-02 00:00 |
02:14:11.33 |
+05:46:57.4 |
HIP 10419 |
13.67 |