| Parameter |
Value |
| Designation |
C/2015 A2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-08-30T11:44:29.256000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:05Z |
| Obs used |
23 |
| NEO |
- |
| M1 |
14.300 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-01-10.0000000 |
| e |
1.01374666 |
| q (au) |
5.266785 |
| a (au) |
-383.131941 |
| i (deg) |
108.899105 |
| Ω (om, deg) |
258.474274 |
| ω (w, deg) |
212.370407 |
| M (ma, deg) |
-0.030555 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.672 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.672 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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 |
17:48:13.58 |
-47:50:51.3 |
HIP 87214 |
12.27 |
| 2026-06-01 12:00 |
17:48:05.83 |
-47:50:48.9 |
HIP 87214 |
13.19 |
| 2026-06-02 00:00 |
17:47:58.07 |
-47:50:46.1 |
HIP 87214 |
14.17 |
| 2026-06-02 12:00 |
17:47:50.29 |
-47:50:43.1 |
HIP 87018 |
13.93 |
| 2026-06-03 00:00 |
17:47:42.49 |
-47:50:39.8 |
HIP 87018 |
13.07 |
| 2026-06-03 12:00 |
17:47:34.67 |
-47:50:36.1 |
HIP 87018 |
12.30 |
| 2026-06-04 00:00 |
17:47:26.84 |
-47:50:32.2 |
HIP 87018 |
11.62 |
| 2026-06-04 12:00 |
17:47:18.99 |
-47:50:28.0 |
HIP 87018 |
11.07 |
| 2026-06-05 00:00 |
17:47:11.13 |
-47:50:23.5 |
HIP 87018 |
10.65 |
| 2026-06-05 12:00 |
17:47:03.25 |
-47:50:18.6 |
HIP 87018 |
10.39 |
| 2026-06-06 00:00 |
17:46:55.36 |
-47:50:13.5 |
HIP 87018 |
10.29 |
| 2026-06-06 12:00 |
17:46:47.46 |
-47:50:08.1 |
HIP 87018 |
10.38 |
| 2026-06-07 00:00 |
17:46:39.54 |
-47:50:02.3 |
HIP 87018 |
10.63 |
| 2026-06-07 12:00 |
17:46:31.61 |
-47:49:56.3 |
HIP 87018 |
11.05 |
| 2026-06-08 00:00 |
17:46:23.67 |
-47:49:50.0 |
HIP 87018 |
11.61 |
| 2026-06-08 12:00 |
17:46:15.72 |
-47:49:43.3 |
HIP 87018 |
12.29 |
| 2026-06-09 00:00 |
17:46:07.76 |
-47:49:36.4 |
HIP 87018 |
13.08 |
| 2026-06-09 12:00 |
17:45:59.79 |
-47:49:29.1 |
HIP 87018 |
13.96 |
| 2026-06-10 00:00 |
17:45:51.82 |
-47:49:21.6 |
HIP 87018 |
14.91 |
| 2026-06-10 12:00 |
17:45:43.83 |
-47:49:13.7 |
HIP 87018 |
15.93 |
| 2026-06-11 00:00 |
17:45:35.84 |
-47:49:05.6 |
HIP 87018 |
16.99 |
| 2026-06-11 12:00 |
17:45:27.84 |
-47:48:57.1 |
HIP 87018 |
18.10 |
| 2026-06-12 00:00 |
17:45:19.83 |
-47:48:48.3 |
HIP 87018 |
19.24 |
| 2026-06-12 12:00 |
17:45:11.82 |
-47:48:39.2 |
HIP 87018 |
20.41 |
| 2026-06-13 00:00 |
17:45:03.80 |
-47:48:29.9 |
HIP 87018 |
21.61 |
| 2026-06-13 12:00 |
17:44:55.78 |
-47:48:20.2 |
HIP 86829 |
22.25 |
| 2026-06-14 00:00 |
17:44:47.76 |
-47:48:10.2 |
HIP 86829 |
21.89 |
| 2026-06-14 12:00 |
17:44:39.73 |
-47:47:59.9 |
HIP 86829 |
21.59 |
| 2026-06-15 00:00 |
17:44:31.70 |
-47:47:49.2 |
HIP 86829 |
21.38 |
| 2026-06-15 12:00 |
17:44:23.67 |
-47:47:38.3 |
HIP 86829 |
21.25 |
| 2026-06-16 00:00 |
17:44:15.64 |
-47:47:27.1 |
HIP 86829 |
21.20 |
| 2026-06-16 12:00 |
17:44:07.61 |
-47:47:15.6 |
HIP 86829 |
21.23 |
| 2026-06-17 00:00 |
17:43:59.59 |
-47:47:03.7 |
HIP 86829 |
21.34 |
| 2026-06-17 12:00 |
17:43:51.56 |
-47:46:51.6 |
HIP 86829 |
21.54 |
| 2026-06-18 00:00 |
17:43:43.53 |
-47:46:39.2 |
HIP 86829 |
21.82 |
| 2026-06-18 12:00 |
17:43:35.51 |
-47:46:26.4 |
HIP 86829 |
22.17 |
| 2026-06-19 00:00 |
17:43:27.49 |
-47:46:13.4 |
HIP 86602 |
22.52 |
| 2026-06-19 12:00 |
17:43:19.48 |
-47:46:00.0 |
HIP 86602 |
21.40 |
| 2026-06-20 00:00 |
17:43:11.47 |
-47:45:46.3 |
HIP 86602 |
20.31 |
| 2026-06-20 12:00 |
17:43:03.47 |
-47:45:32.4 |
HIP 86602 |
19.25 |
| 2026-06-21 00:00 |
17:42:55.47 |
-47:45:18.1 |
HIP 86602 |
18.22 |
| 2026-06-21 12:00 |
17:42:47.49 |
-47:45:03.6 |
HIP 86602 |
17.25 |
| 2026-06-22 00:00 |
17:42:39.50 |
-47:44:48.7 |
HIP 86602 |
16.32 |