| Parameter |
Value |
| Designation |
C/2015 J1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2014-06-29T23:13:39.259200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:10Z |
| Obs used |
54 |
| NEO |
- |
| M1 |
7.500 |
| K1 |
11.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-08-08.0000000 |
| e |
1.00318272 |
| q (au) |
6.019565 |
| a (au) |
-1891.328665 |
| i (deg) |
94.998299 |
| Ω (om, deg) |
219.992187 |
| ω (w, deg) |
315.467882 |
| M (ma, deg) |
0.004841 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.428 + 5.041\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.428 |
| n |
5.041 |
| gf |
1.000 |
| gb |
-0.998 |
| 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 |
16:16:27.30 |
+60:45:11.0 |
HIP 79718 |
8.43 |
| 2026-05-12 12:00 |
16:16:18.58 |
+60:45:40.2 |
HIP 79718 |
7.77 |
| 2026-05-13 00:00 |
16:16:09.83 |
+60:46:08.8 |
HIP 79718 |
7.25 |
| 2026-05-13 12:00 |
16:16:01.07 |
+60:46:36.8 |
HIP 79718 |
6.91 |
| 2026-05-14 00:00 |
16:15:52.28 |
+60:47:04.2 |
HIP 79718 |
6.76 |
| 2026-05-14 12:00 |
16:15:43.47 |
+60:47:30.9 |
HIP 79718 |
6.81 |
| 2026-05-15 00:00 |
16:15:34.64 |
+60:47:57.0 |
HIP 79718 |
7.08 |
| 2026-05-15 12:00 |
16:15:25.80 |
+60:48:22.5 |
HIP 79718 |
7.52 |
| 2026-05-16 00:00 |
16:15:16.93 |
+60:48:47.3 |
HIP 79718 |
8.11 |
| 2026-05-16 12:00 |
16:15:08.05 |
+60:49:11.5 |
HIP 79718 |
8.82 |
| 2026-05-17 00:00 |
16:14:59.15 |
+60:49:35.0 |
HIP 79629 |
9.46 |
| 2026-05-17 12:00 |
16:14:50.24 |
+60:49:57.9 |
HIP 79629 |
9.88 |
| 2026-05-18 00:00 |
16:14:41.31 |
+60:50:20.2 |
HIP 79629 |
10.39 |
| 2026-05-18 12:00 |
16:14:32.37 |
+60:50:41.8 |
HIP 79629 |
11.00 |
| 2026-05-19 00:00 |
16:14:23.41 |
+60:51:02.8 |
HIP 79629 |
11.67 |
| 2026-05-19 12:00 |
16:14:14.45 |
+60:51:23.1 |
HIP 79629 |
12.41 |
| 2026-05-20 00:00 |
16:14:05.47 |
+60:51:42.8 |
HIP 79629 |
13.19 |
| 2026-05-20 12:00 |
16:13:56.49 |
+60:52:01.9 |
HIP 79629 |
14.02 |
| 2026-05-21 00:00 |
16:13:47.49 |
+60:52:20.3 |
HIP 79629 |
14.88 |
| 2026-05-21 12:00 |
16:13:38.49 |
+60:52:38.0 |
HIP 79629 |
15.76 |
| 2026-05-22 00:00 |
16:13:29.48 |
+60:52:55.1 |
HIP 79629 |
16.67 |
| 2026-05-22 12:00 |
16:13:20.46 |
+60:53:11.6 |
HIP 79629 |
17.60 |
| 2026-05-23 00:00 |
16:13:11.44 |
+60:53:27.5 |
HIP 79629 |
18.55 |
| 2026-05-23 12:00 |
16:13:02.41 |
+60:53:42.7 |
HIP 79629 |
19.50 |
| 2026-05-24 00:00 |
16:12:53.38 |
+60:53:57.2 |
HIP 79345 |
20.35 |
| 2026-05-24 12:00 |
16:12:44.35 |
+60:54:11.1 |
HIP 79345 |
19.65 |
| 2026-05-25 00:00 |
16:12:35.31 |
+60:54:24.4 |
HIP 79345 |
19.01 |
| 2026-05-25 12:00 |
16:12:26.28 |
+60:54:37.0 |
HIP 79345 |
18.42 |
| 2026-05-26 00:00 |
16:12:17.24 |
+60:54:49.0 |
HIP 79345 |
17.89 |
| 2026-05-26 12:00 |
16:12:08.20 |
+60:55:00.3 |
HIP 79345 |
17.42 |
| 2026-05-27 00:00 |
16:11:59.17 |
+60:55:11.0 |
HIP 79345 |
17.03 |
| 2026-05-27 12:00 |
16:11:50.14 |
+60:55:21.1 |
HIP 79345 |
16.71 |
| 2026-05-28 00:00 |
16:11:41.11 |
+60:55:30.5 |
HIP 79345 |
16.47 |
| 2026-05-28 12:00 |
16:11:32.08 |
+60:55:39.3 |
HIP 79345 |
16.31 |
| 2026-05-29 00:00 |
16:11:23.06 |
+60:55:47.5 |
HIP 79345 |
16.24 |
| 2026-05-29 12:00 |
16:11:14.04 |
+60:55:55.0 |
HIP 79345 |
16.25 |
| 2026-05-30 00:00 |
16:11:05.03 |
+60:56:01.9 |
HIP 79345 |
16.34 |
| 2026-05-30 12:00 |
16:10:56.02 |
+60:56:08.1 |
HIP 79345 |
16.52 |
| 2026-05-31 00:00 |
16:10:47.03 |
+60:56:13.7 |
HIP 79345 |
16.77 |
| 2026-05-31 12:00 |
16:10:38.04 |
+60:56:18.7 |
HIP 79345 |
17.11 |
| 2026-06-01 00:00 |
16:10:29.06 |
+60:56:23.1 |
HIP 79345 |
17.51 |
| 2026-06-01 12:00 |
16:10:20.09 |
+60:56:26.8 |
HIP 79345 |
17.98 |
| 2026-06-02 00:00 |
16:10:11.13 |
+60:56:29.8 |
HIP 79345 |
18.50 |