| Parameter |
Value |
| Designation |
C/2015 M1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-05-15T16:23:58.865280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:13Z |
| Obs used |
66 |
| NEO |
- |
| M1 |
15.900 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-06-30.0000000 |
| e |
0.99457925 |
| q (au) |
2.091599 |
| a (au) |
385.850445 |
| i (deg) |
57.309532 |
| Ω (om, deg) |
100.291624 |
| ω (w, deg) |
163.983025 |
| M (ma, deg) |
0.005893 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.909 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.909 |
| n |
2.000 |
| gf |
0.933 |
| gb |
-1.000 |
| k |
0.998 |
| δ90 |
1.000 |
| 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 |
04:51:10.99 |
-15:32:43.3 |
HIP 22467 |
21.91 |
| 2026-06-01 12:00 |
04:51:15.72 |
-15:32:30.3 |
HIP 22467 |
22.88 |
| 2026-06-02 00:00 |
04:51:20.45 |
-15:32:17.7 |
HIP 22467 |
23.86 |
| 2026-06-02 12:00 |
04:51:25.18 |
-15:32:05.4 |
HIP 22467 |
24.85 |
| 2026-06-03 00:00 |
04:51:29.92 |
-15:31:53.4 |
HIP 22467 |
25.85 |
| 2026-06-03 12:00 |
04:51:34.65 |
-15:31:41.7 |
HIP 22467 |
26.86 |
| 2026-06-04 00:00 |
04:51:39.39 |
-15:31:30.4 |
HIP 22467 |
27.88 |
| 2026-06-04 12:00 |
04:51:44.12 |
-15:31:19.5 |
HIP 22625 |
28.58 |
| 2026-06-05 00:00 |
04:51:48.85 |
-15:31:08.8 |
HIP 22625 |
28.24 |
| 2026-06-05 12:00 |
04:51:53.59 |
-15:30:58.6 |
HIP 22625 |
27.94 |
| 2026-06-06 00:00 |
04:51:58.32 |
-15:30:48.6 |
HIP 22625 |
27.69 |
| 2026-06-06 12:00 |
04:52:03.05 |
-15:30:39.0 |
HIP 22625 |
27.49 |
| 2026-06-07 00:00 |
04:52:07.79 |
-15:30:29.7 |
HIP 22625 |
27.34 |
| 2026-06-07 12:00 |
04:52:12.52 |
-15:30:20.8 |
HIP 22625 |
27.25 |
| 2026-06-08 00:00 |
04:52:17.24 |
-15:30:12.2 |
HIP 22625 |
27.21 |
| 2026-06-08 12:00 |
04:52:21.97 |
-15:30:03.9 |
HIP 22625 |
27.23 |
| 2026-06-09 00:00 |
04:52:26.69 |
-15:29:56.0 |
HIP 22625 |
27.30 |
| 2026-06-09 12:00 |
04:52:31.41 |
-15:29:48.4 |
HIP 22625 |
27.42 |
| 2026-06-10 00:00 |
04:52:36.13 |
-15:29:41.1 |
HIP 22625 |
27.60 |
| 2026-06-10 12:00 |
04:52:40.85 |
-15:29:34.2 |
HIP 22625 |
27.83 |
| 2026-06-11 00:00 |
04:52:45.56 |
-15:29:27.7 |
HIP 22625 |
28.10 |
| 2026-06-11 12:00 |
04:52:50.26 |
-15:29:21.5 |
HIP 22625 |
28.43 |
| 2026-06-12 00:00 |
04:52:54.97 |
-15:29:15.6 |
HIP 22625 |
28.80 |
| 2026-06-12 12:00 |
04:52:59.67 |
-15:29:10.0 |
HIP 22625 |
29.21 |
| 2026-06-13 00:00 |
04:53:04.36 |
-15:29:04.9 |
HIP 22625 |
29.67 |
| 2026-06-13 12:00 |
04:53:09.05 |
-15:29:00.0 |
HIP 22625 |
30.17 |
| 2026-06-14 00:00 |
04:53:13.73 |
-15:28:55.5 |
HIP 22625 |
30.70 |
| 2026-06-14 12:00 |
04:53:18.41 |
-15:28:51.3 |
HIP 22625 |
31.28 |
| 2026-06-15 00:00 |
04:53:23.09 |
-15:28:47.5 |
HIP 22625 |
31.88 |
| 2026-06-15 12:00 |
04:53:27.75 |
-15:28:44.0 |
HIP 22625 |
32.52 |
| 2026-06-16 00:00 |
04:53:32.41 |
-15:28:40.9 |
HIP 22625 |
33.18 |
| 2026-06-16 12:00 |
04:53:37.06 |
-15:28:38.1 |
HIP 22790 |
33.10 |
| 2026-06-17 00:00 |
04:53:41.71 |
-15:28:35.7 |
HIP 22790 |
32.79 |
| 2026-06-17 12:00 |
04:53:46.35 |
-15:28:33.5 |
HIP 22790 |
32.53 |
| 2026-06-18 00:00 |
04:53:50.98 |
-15:28:31.8 |
HIP 22790 |
32.31 |
| 2026-06-18 12:00 |
04:53:55.60 |
-15:28:30.3 |
HIP 22790 |
32.14 |
| 2026-06-19 00:00 |
04:54:00.22 |
-15:28:29.3 |
HIP 22790 |
32.00 |
| 2026-06-19 12:00 |
04:54:04.82 |
-15:28:28.5 |
HIP 22790 |
31.92 |
| 2026-06-20 00:00 |
04:54:09.42 |
-15:28:28.1 |
HIP 22790 |
31.87 |
| 2026-06-20 12:00 |
04:54:14.00 |
-15:28:28.0 |
HIP 22790 |
31.87 |
| 2026-06-21 00:00 |
04:54:18.58 |
-15:28:28.3 |
HIP 22962 |
31.28 |
| 2026-06-21 12:00 |
04:54:23.15 |
-15:28:28.9 |
HIP 22962 |
30.20 |
| 2026-06-22 00:00 |
04:54:27.71 |
-15:28:29.9 |
HIP 22962 |
29.13 |