| Parameter |
Value |
| Designation |
P/2015 A3 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2015-02-22T20:59:44.802240Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:05Z |
| Obs used |
57 |
| NEO |
Yes |
| M1 |
20.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-02-14.0000000 |
| e |
0.84590960 |
| q (au) |
1.152929 |
| a (au) |
7.482163 |
| i (deg) |
172.510659 |
| Ω (om, deg) |
277.075159 |
| ω (w, deg) |
249.619923 |
| M (ma, deg) |
359.572611 |
Magnitude
Scatter + Global Linear
$$
M_a = (20.000 + 3.323\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
20.000 |
| n |
3.323 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.939 |
| 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 |
13:35:03.30 |
-01:42:54.8 |
HIP 66391 |
37.11 |
| 2026-05-12 12:00 |
13:34:54.61 |
-01:42:11.9 |
HIP 66391 |
38.12 |
| 2026-05-13 00:00 |
13:34:45.96 |
-01:41:29.4 |
HIP 66391 |
39.23 |
| 2026-05-13 12:00 |
13:34:37.34 |
-01:40:47.2 |
HIP 66391 |
40.43 |
| 2026-05-14 00:00 |
13:34:28.76 |
-01:40:05.4 |
HIP 66391 |
41.72 |
| 2026-05-14 12:00 |
13:34:20.22 |
-01:39:24.0 |
HIP 66391 |
43.08 |
| 2026-05-15 00:00 |
13:34:11.72 |
-01:38:42.9 |
HIP 65987 |
44.02 |
| 2026-05-15 12:00 |
13:34:03.26 |
-01:38:02.3 |
HIP 65987 |
41.89 |
| 2026-05-16 00:00 |
13:33:54.84 |
-01:37:21.9 |
HIP 65987 |
39.78 |
| 2026-05-16 12:00 |
13:33:46.47 |
-01:36:42.0 |
HIP 65987 |
37.69 |
| 2026-05-17 00:00 |
13:33:38.13 |
-01:36:02.4 |
HIP 65987 |
35.63 |
| 2026-05-17 12:00 |
13:33:29.84 |
-01:35:23.3 |
HIP 65987 |
33.59 |
| 2026-05-18 00:00 |
13:33:21.59 |
-01:34:44.5 |
HIP 65987 |
31.59 |
| 2026-05-18 12:00 |
13:33:13.38 |
-01:34:06.1 |
HIP 65987 |
29.62 |
| 2026-05-19 00:00 |
13:33:05.22 |
-01:33:28.1 |
HIP 65987 |
27.69 |
| 2026-05-19 12:00 |
13:32:57.10 |
-01:32:50.5 |
HIP 65987 |
25.81 |
| 2026-05-20 00:00 |
13:32:49.03 |
-01:32:13.3 |
HIP 65987 |
23.98 |
| 2026-05-20 12:00 |
13:32:41.01 |
-01:31:36.5 |
HIP 65987 |
22.21 |
| 2026-05-21 00:00 |
13:32:33.03 |
-01:31:00.1 |
HIP 65987 |
20.52 |
| 2026-05-21 12:00 |
13:32:25.10 |
-01:30:24.1 |
HIP 65987 |
18.92 |
| 2026-05-22 00:00 |
13:32:17.22 |
-01:29:48.5 |
HIP 65987 |
17.42 |
| 2026-05-22 12:00 |
13:32:09.39 |
-01:29:13.3 |
HIP 65987 |
16.07 |
| 2026-05-23 00:00 |
13:32:01.61 |
-01:28:38.5 |
HIP 65987 |
14.88 |
| 2026-05-23 12:00 |
13:31:53.87 |
-01:28:04.1 |
HIP 65987 |
13.89 |
| 2026-05-24 00:00 |
13:31:46.19 |
-01:27:30.1 |
HIP 65987 |
13.15 |
| 2026-05-24 12:00 |
13:31:38.55 |
-01:26:56.6 |
HIP 65987 |
12.69 |
| 2026-05-25 00:00 |
13:31:30.97 |
-01:26:23.5 |
HIP 65987 |
12.54 |
| 2026-05-25 12:00 |
13:31:23.44 |
-01:25:50.7 |
HIP 65987 |
12.70 |
| 2026-05-26 00:00 |
13:31:15.96 |
-01:25:18.4 |
HIP 65987 |
13.14 |
| 2026-05-26 12:00 |
13:31:08.53 |
-01:24:46.5 |
HIP 65987 |
13.85 |
| 2026-05-27 00:00 |
13:31:01.16 |
-01:24:15.1 |
HIP 65987 |
14.77 |
| 2026-05-27 12:00 |
13:30:53.84 |
-01:23:44.0 |
HIP 65987 |
15.87 |
| 2026-05-28 00:00 |
13:30:46.57 |
-01:23:13.4 |
HIP 65840 |
14.83 |
| 2026-05-28 12:00 |
13:30:39.36 |
-01:22:43.2 |
HIP 65840 |
13.06 |
| 2026-05-29 00:00 |
13:30:32.20 |
-01:22:13.4 |
HIP 65840 |
11.33 |
| 2026-05-29 12:00 |
13:30:25.10 |
-01:21:44.1 |
HIP 65840 |
9.67 |
| 2026-05-30 00:00 |
13:30:18.05 |
-01:21:15.2 |
HIP 65840 |
8.10 |
| 2026-05-30 12:00 |
13:30:11.05 |
-01:20:46.7 |
HIP 65840 |
6.67 |
| 2026-05-31 00:00 |
13:30:04.12 |
-01:20:18.6 |
HIP 65840 |
5.47 |
| 2026-05-31 12:00 |
13:29:57.24 |
-01:19:51.0 |
HIP 65840 |
4.68 |
| 2026-06-01 00:00 |
13:29:50.41 |
-01:19:23.8 |
HIP 65840 |
4.49 |
| 2026-06-01 12:00 |
13:29:43.65 |
-01:18:57.0 |
HIP 65840 |
4.95 |
| 2026-06-02 00:00 |
13:29:36.94 |
-01:18:30.7 |
HIP 65840 |
5.90 |