| 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 |
0.926 |
| 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) |
| 2026-05-12 00:00 |
04:48:06.16 |
-15:45:51.4 |
HIP 22398 |
16.63 |
| 2026-05-12 12:00 |
04:48:10.60 |
-15:45:25.4 |
HIP 22398 |
15.50 |
| 2026-05-13 00:00 |
04:48:15.06 |
-15:44:59.8 |
HIP 22398 |
14.38 |
| 2026-05-13 12:00 |
04:48:19.52 |
-15:44:34.5 |
HIP 22398 |
13.26 |
| 2026-05-14 00:00 |
04:48:24.00 |
-15:44:09.5 |
HIP 22398 |
12.15 |
| 2026-05-14 12:00 |
04:48:28.49 |
-15:43:44.8 |
HIP 22398 |
11.04 |
| 2026-05-15 00:00 |
04:48:33.00 |
-15:43:20.4 |
HIP 22398 |
9.94 |
| 2026-05-15 12:00 |
04:48:37.51 |
-15:42:56.4 |
HIP 22398 |
8.85 |
| 2026-05-16 00:00 |
04:48:42.04 |
-15:42:32.6 |
HIP 22398 |
7.78 |
| 2026-05-16 12:00 |
04:48:46.57 |
-15:42:09.2 |
HIP 22398 |
6.74 |
| 2026-05-17 00:00 |
04:48:51.12 |
-15:41:46.0 |
HIP 22398 |
5.73 |
| 2026-05-17 12:00 |
04:48:55.68 |
-15:41:23.2 |
HIP 22398 |
4.79 |
| 2026-05-18 00:00 |
04:49:00.25 |
-15:41:00.8 |
HIP 22398 |
3.96 |
| 2026-05-18 12:00 |
04:49:04.83 |
-15:40:38.6 |
HIP 22398 |
3.34 |
| 2026-05-19 00:00 |
04:49:09.41 |
-15:40:16.7 |
HIP 22398 |
3.04 |
| 2026-05-19 12:00 |
04:49:14.01 |
-15:39:55.2 |
HIP 22398 |
3.16 |
| 2026-05-20 00:00 |
04:49:18.61 |
-15:39:34.0 |
HIP 22398 |
3.67 |
| 2026-05-20 12:00 |
04:49:23.23 |
-15:39:13.1 |
HIP 22398 |
4.42 |
| 2026-05-21 00:00 |
04:49:27.85 |
-15:38:52.6 |
HIP 22398 |
5.32 |
| 2026-05-21 12:00 |
04:49:32.48 |
-15:38:32.4 |
HIP 22398 |
6.31 |
| 2026-05-22 00:00 |
04:49:37.11 |
-15:38:12.4 |
HIP 22442 |
6.50 |
| 2026-05-22 12:00 |
04:49:41.76 |
-15:37:52.9 |
HIP 22442 |
6.62 |
| 2026-05-23 00:00 |
04:49:46.41 |
-15:37:33.6 |
HIP 22442 |
6.93 |
| 2026-05-23 12:00 |
04:49:51.07 |
-15:37:14.7 |
HIP 22442 |
7.41 |
| 2026-05-24 00:00 |
04:49:55.73 |
-15:36:56.1 |
HIP 22442 |
8.02 |
| 2026-05-24 12:00 |
04:50:00.40 |
-15:36:37.8 |
HIP 22442 |
8.74 |
| 2026-05-25 00:00 |
04:50:05.08 |
-15:36:19.9 |
HIP 22442 |
9.55 |
| 2026-05-25 12:00 |
04:50:09.76 |
-15:36:02.3 |
HIP 22442 |
10.42 |
| 2026-05-26 00:00 |
04:50:14.44 |
-15:35:45.0 |
HIP 22442 |
11.34 |
| 2026-05-26 12:00 |
04:50:19.14 |
-15:35:28.0 |
HIP 22442 |
12.30 |
| 2026-05-27 00:00 |
04:50:23.83 |
-15:35:11.4 |
HIP 22442 |
13.29 |
| 2026-05-27 12:00 |
04:50:28.53 |
-15:34:55.1 |
HIP 22442 |
14.30 |
| 2026-05-28 00:00 |
04:50:33.24 |
-15:34:39.1 |
HIP 22467 |
15.02 |
| 2026-05-28 12:00 |
04:50:37.95 |
-15:34:23.5 |
HIP 22467 |
15.76 |
| 2026-05-29 00:00 |
04:50:42.66 |
-15:34:08.2 |
HIP 22467 |
16.55 |
| 2026-05-29 12:00 |
04:50:47.37 |
-15:33:53.2 |
HIP 22467 |
17.37 |
| 2026-05-30 00:00 |
04:50:52.09 |
-15:33:38.5 |
HIP 22467 |
18.23 |
| 2026-05-30 12:00 |
04:50:56.81 |
-15:33:24.2 |
HIP 22467 |
19.12 |
| 2026-05-31 00:00 |
04:51:01.54 |
-15:33:10.3 |
HIP 22467 |
20.03 |
| 2026-05-31 12:00 |
04:51:06.26 |
-15:32:56.6 |
HIP 22467 |
20.96 |
| 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 |