| Parameter |
Value |
| Designation |
C/2015 K2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-06-08T19:07:06.248640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:11Z |
| Obs used |
54 |
| NEO |
- |
| M1 |
20.700 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-05-26.0000000 |
| e |
0.99444359 |
| q (au) |
1.455282 |
| a (au) |
261.910605 |
| i (deg) |
29.110346 |
| Ω (om, deg) |
223.713883 |
| ω (w, deg) |
15.770089 |
| M (ma, deg) |
359.996792 |
Magnitude
Scatter + Global Linear
$$
M_a = (20.000 + 3.100\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
20.000 |
| n |
3.100 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-07-29 00:00 |
02:09:43.71 |
+18:36:31.1 |
HIP 9924 |
44.59 |
| 2026-07-29 12:00 |
02:09:43.86 |
+18:36:36.0 |
HIP 9924 |
44.68 |
| 2026-07-30 00:00 |
02:09:43.97 |
+18:36:40.7 |
HIP 9924 |
44.76 |
| 2026-07-30 12:00 |
02:09:44.04 |
+18:36:45.2 |
HIP 9924 |
44.83 |
| 2026-07-31 00:00 |
02:09:44.07 |
+18:36:49.6 |
HIP 9924 |
44.89 |
| 2026-07-31 12:00 |
02:09:44.07 |
+18:36:53.7 |
HIP 9924 |
44.94 |
| 2026-08-01 00:00 |
02:09:44.03 |
+18:36:57.7 |
HIP 9924 |
44.99 |
| 2026-08-01 12:00 |
02:09:43.96 |
+18:37:01.4 |
HIP 9924 |
45.02 |
| 2026-08-02 00:00 |
02:09:43.84 |
+18:37:05.0 |
HIP 9924 |
45.05 |
| 2026-08-02 12:00 |
02:09:43.69 |
+18:37:08.4 |
HIP 9924 |
45.08 |
| 2026-08-03 00:00 |
02:09:43.50 |
+18:37:11.6 |
HIP 9924 |
45.09 |
| 2026-08-03 12:00 |
02:09:43.28 |
+18:37:14.6 |
HIP 9924 |
45.10 |
| 2026-08-04 00:00 |
02:09:43.02 |
+18:37:17.5 |
HIP 9924 |
45.10 |
| 2026-08-04 12:00 |
02:09:42.72 |
+18:37:20.1 |
HIP 9924 |
45.09 |
| 2026-08-05 00:00 |
02:09:42.38 |
+18:37:22.5 |
HIP 9924 |
45.07 |
| 2026-08-05 12:00 |
02:09:42.01 |
+18:37:24.8 |
HIP 9924 |
45.05 |
| 2026-08-06 00:00 |
02:09:41.60 |
+18:37:26.8 |
HIP 9924 |
45.01 |
| 2026-08-06 12:00 |
02:09:41.15 |
+18:37:28.7 |
HIP 9924 |
44.97 |
| 2026-08-07 00:00 |
02:09:40.67 |
+18:37:30.3 |
HIP 9924 |
44.92 |
| 2026-08-07 12:00 |
02:09:40.14 |
+18:37:31.8 |
HIP 9924 |
44.87 |
| 2026-08-08 00:00 |
02:09:39.58 |
+18:37:33.1 |
HIP 9924 |
44.81 |
| 2026-08-08 12:00 |
02:09:38.99 |
+18:37:34.2 |
HIP 9924 |
44.74 |
| 2026-08-09 00:00 |
02:09:38.35 |
+18:37:35.0 |
HIP 9924 |
44.66 |
| 2026-08-09 12:00 |
02:09:37.68 |
+18:37:35.7 |
HIP 9924 |
44.57 |
| 2026-08-10 00:00 |
02:09:36.97 |
+18:37:36.2 |
HIP 9924 |
44.48 |
| 2026-08-10 12:00 |
02:09:36.23 |
+18:37:36.5 |
HIP 9924 |
44.38 |
| 2026-08-11 00:00 |
02:09:35.45 |
+18:37:36.6 |
HIP 9924 |
44.27 |
| 2026-08-11 12:00 |
02:09:34.63 |
+18:37:36.5 |
HIP 9924 |
44.15 |
| 2026-08-12 00:00 |
02:09:33.77 |
+18:37:36.2 |
HIP 9924 |
44.03 |
| 2026-08-12 12:00 |
02:09:32.88 |
+18:37:35.7 |
HIP 9924 |
43.90 |
| 2026-08-13 00:00 |
02:09:31.95 |
+18:37:35.0 |
HIP 9924 |
43.76 |
| 2026-08-13 12:00 |
02:09:30.98 |
+18:37:34.1 |
HIP 9924 |
43.62 |
| 2026-08-14 00:00 |
02:09:29.97 |
+18:37:33.0 |
HIP 9924 |
43.47 |
| 2026-08-14 12:00 |
02:09:28.93 |
+18:37:31.7 |
HIP 9924 |
43.31 |
| 2026-08-15 00:00 |
02:09:27.85 |
+18:37:30.2 |
HIP 9924 |
43.15 |
| 2026-08-15 12:00 |
02:09:26.74 |
+18:37:28.5 |
HIP 9924 |
42.98 |
| 2026-08-16 00:00 |
02:09:25.59 |
+18:37:26.6 |
HIP 9924 |
42.80 |
| 2026-08-16 12:00 |
02:09:24.40 |
+18:37:24.4 |
HIP 9824 |
42.59 |
| 2026-08-17 00:00 |
02:09:23.18 |
+18:37:22.1 |
HIP 9824 |
42.30 |
| 2026-08-17 12:00 |
02:09:21.92 |
+18:37:19.6 |
HIP 9824 |
42.00 |
| 2026-08-18 00:00 |
02:09:20.62 |
+18:37:16.9 |
HIP 9824 |
41.69 |
| 2026-08-18 12:00 |
02:09:19.29 |
+18:37:14.0 |
HIP 9824 |
41.37 |
| 2026-08-19 00:00 |
02:09:17.92 |
+18:37:10.9 |
HIP 9824 |
41.04 |